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Cooling System Cleaning

15K views 37 replies 9 participants last post by  cushjbc 
#1 ·
It is time to flush out my cooling system; had an indie do it for me 2 years ago - or so I thought. This is a first for me so I researched it here on the forum, and used the procedures in the maintenance manual (20-010). The cooling system has not performed well in central New Mexico so I planned a de-oiling and de-scaling (20-015).

I drained the radiator first - green coolant with lots of contaminant in it. When I opened the block drains, nothing happened. I pulled both block drains and found hardened crud in the passages. I used a pick and small wire pipe brush to clean it out and drain the block. Clearly, I have coolant passage problems.

I made a degrease solution and ran the car for about 20' with that in there - I will flush it out and repeat tomorrow. The Citric Acid treatment will follow.

The last picture is a pick stuck in the gunk clogging my block drain.
 

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#2 ·
I don't think de-oiling is going to fix this problem.


The citric acid flush might after a bunch of flushes and re-dos. Unfortunately anything that un-cruds might get lodged in your rad or somewheres else.

When is the last time the rad went to a rad shop for a good going over?
 
#3 ·
Nobby,

This indie that I spoke of rebuilt my A/C system. When he was done, he found that the car ran really hot with the A/C running. He pulled the radiator and sent it off for a boil out and whatever else they do. I'll spare you the trauma that I went though in 3 months getting an A/C system rebuilt - bottom line; never going back, doing my own work.

I agree with the necessity of a citric acid flush. The main reason I'm doing the de-oiling is because 20-015 says do it before you to the acid. Apparently, this enables the chemistry to work better.

I did not order enough citric acid. The maintenance manual calls for a 10% solution which amounts to 1.5KG for the M117. I bought a single jar - 500g. I'm going to visit this crazy Iranian pharmacist tomorrow. If he doesn't have citric acid, I'll go back to MB of ABQ and wait 3 days.
 
#4 ·
I did not order enough citric acid. The maintenance manual calls for a 10% solution which amounts to 1.5KG for the M117. I bought a single jar - 500g. I'm going to visit this crazy Iranian pharmacist tomorrow. If he doesn't have citric acid, I'll go back to MB of ABQ and wait 3 days.
Try your local WallyWorld, the one by me stocks Ball brand (the canning people)
citric acid. One of our local brew houses also stocks it, but that
usually ends up costing me more :beerchugr:



Fish
 
#5 · (Edited)
I bought a 5 kg bag on eBay for 10$.

What I did on my OM617 and OM603 was to make a block flusher out of galvanized pipe connected to a valve connected to about 6feet of hose. I screwed the pipe into the block drain connected the hose to the garden hose and ran water through the engine and out the lower radiator hose which I disconnected from the radiator. When the gunk stopped coming out, I hooked up the radiator hose, filled the system from the block, then shit the valve on the pipe. I added the citric acid and ran the engine for a half hour. I opened the valve and drained the acid, hooked the drain hose back to the garden hose and reverse flushed for 15 minutes with the engine running. I repeated this twice. On our V8s with two drains I would use two pipe-valve set ups.here is a picture of the dingus...
 

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#6 ·
I struck out finding local sources for citric acid monohydrate - ordered 2 more jars of MB citric acid. In the meantime, I de-oiled twice and did a flush. I bought a generic flush kit years ago - opened it today and put it to good use.

When I looked at the coolant circuit of the M117, I found a convenient place to introduce fresh water was at the heater faucet. The fitting is 20mm which is very close to 3/4". I bought a 6' length of 3/4" ID heater hose from Autozone. I used a 3/4" T fitting with a check valve, opened the heater faucet (full heat), and removed the radiator drain plug. I ran one hose to the check valve and another hose to the coolant reservoir. I started the engine and let it run for about 10' until the water was clear and suds free.

Next step is another drain procedure followed by the citric acid.
 

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#7 ·
I finished this project today. Used 1.5KG of citric acid from MB (pictured above) because I could not find a cheaper substitute in ABQ. I followed the instructions in article 20-015 by de-oiling the cooling system 3 times then flushing until I had nothing but clear water flowing from the radiator and block drains.

The descaling operation is pretty straight forward. I drained the cooling system (4th time), flushed the system until clear since my car sat for a week. I removed the alternator to gain easy access to the thermostat housing, removed 3 x 10mm bolts to remove the thermostat, then replaced the housing and the old thermostat seal for the descaling step. I used a 5 liter medical tub to mix the solution. The MB stuff is dry white crystals that dissolve easily. I slowly poured this solution into the coolant reservoir. The first 10 liters went in easily, I had to run the engine and burp the system to get the last 5 liters in.

I had a slow leak at the thermostat housing because the seal is not as effective without the shape of the thermostat supporting it inside. If I were going to do this again, I would drill out the old thermostat and use the thermostat frame to make a better seal. This small leak I had makes for a real mess when you do the engine run.

I was amazed when I drained this solution. The fluid that came out was a sticky green Kool-Aid looking stuff that had white grit in it. It took several flushes to get a clear flow again. I think the citric acid is effective at getting congealed coolant from recessed areas; I think the grit must have been hard water deposits and maybe some rusty film. When I put the new thermostat in, The water pump intake and thermostat housing were hospital clean.

In the end, I filled the cooling system with 5 liters of Zerex and 10 liters of distilled water. I am remiss in not using a camera today - I know the rules. I struggled with the mess and a very hot day in Albuquerque and decided not to pause for pictures.
 
#8 ·
Hi Brad,

I just caught this thread. I'm not sure if you remember me mentioning this when we caught up last - but the removal of the radiator and thermostat is necessary to really get it to work well. The problem is, how do you keep circulating the solution for the minimum 15 minutes??? And you really need to do it for an hour or more if it is possible, when things look bleak.

well I don't know if you have a 20 gallon drum, or even if you have a spare 5 gallon drum laying around, but I found them invaluable for things like this.

My family has a few plumbers so for me some things are easy to do / get hold of.

1. 5 gallon drum - large paint tin works.... as you can take the lid off and see all the junk...
2. some 2" or 1 ¾" copper tube. (about 1 foot length cut into 4 pc.)
3. holesaw
4.brazing torch.
5. 2" rubber hose - or old radiator hoses
6. small stepladder to sit the drum on in front of the car while it's running.

the citric acid you grab from a home-brew place. citric is used to clean out carboys for brewing..... save $$$ and buy bulk.

prep:
cut a 2" dia hole (or whatever the diameter of your copper / pipe) in the drum at ¾ height, and another at ½ height . braze in 2 pieces of the 4 pc of copper into these holes. It helps if you angle the inlet pipe at the top to create a vortex with the inlet flow. make sure the outlet is at 90º though, (inlet at top, outlet is bottom) like a swirl pot - which is essentially what we are making - on a large scale.
Grab your old rad hoses or if you're flush, some irrigation pipe or other material to join the top and bottom hoses to the drum, using the other 2 pieces of copper and some matching hose clamps.
If your rad hoses are smaller, use smaller pipe if need be. so long as it can form a cooling system loop it doesn't matter how you achieve it. All you're looking for is a substitute radiator.... which is what the 5 gallon drum /paint tin is.
Once it's all hooked up, sit the drum on a ladder to elevate it above the thermostat housing & header tank height.... hence small stepladder or barstool.... remember it's going to get HOT, so don't put it on something that will melt.

Fill the drum up past the inlet pipe. Add the citric acid (about 3-5KG) stir it around until it dissolves and start the car. let the car warm up. At this stage, do not give it any revs. all you want is coolant circulation and no air pockets.
The car will warm up, it will take time as there is more coolant circulating in the system.
You can leave it for an hour or so, and it will be fine. while the coolant is circulating, you will notice some bits of rusty crud falling to the bottom of the drum. This is why you want that outlet higher up on the side, so you don't pick up that crud and recirculate it. You can put a stocking over the bottom pipe stub before you fir the hose to it, to act as a further filter.

Once you are happy with the flush - (bear in mind you can drain and repeat it until the coolant is clear, within reason), you must thoroughly rinse flush the system. best way to do this is with a garden hose, straight into the bottom hose inlet, and car off. let it run on a medium flow for about 15 minutes, which is what it will take to thoroughly neutralize the acid.

That's part 1.

Part 2 is more sensitive. It's about the radiator core.

If you have a brass tank / copper core, then you need to be careful when acid cleaning. If you have an alloy core plastic tank, then you need to worry a fraction less, but you do need a different solution to clean each one.
for copper tank you can use zinc chloride - aka soldering fluid. buy off the shelf or make your own with some zinc and muriatic acid. either way - whatever is cheapest and easiest.
fill the core with a diluted solution, soak for a minute, drain, rinse with water, repeat.

If this is not working, then you can use a slightly higher concentrate, but beware.... an old core is an unknown, and any acid wash or dip can pinhole cores - particularly old ones which have seen many years of internally corrosive fluids.
This will ensure that any passages that are not blocked, will flow cleanly. It does not guarantee that any cores which are badly blocked, will be unblocked. Chemical treatments can only go so far.

The copper / brass radiators are usually soldered with a low-temp solder, and it's easy to take the radiator to a specialist rad guy, to desolder the tank and wire through the cores as well as acid dip, resolder and respray. This will get you some extended life and is a better alternative...HOWEVER -

If the core is 10 years old or more, do yourself a favour and have the rad re-cored.
The overheating issue I had was difficult to diagnose. ended up replacing every part of the cooling system, pumps, tanks, hoses, visco coupling... t-stats etc... (but the rad was flowing heaps, and i mean heaps. the fire hose in my work basement proved this) All except the radiator. Why? because the FIRST thing I did was citric flush and pull the rad and flushed that several times, and it looked like it was absolutely perfectly serviceable.
I finally took the rad to get recored as the last straw. - i'd done the acid clean, everything....

So I had my SLC recored by a specialist guy who does serious earthmoving equipment.
He pulled the tanks off, found the core to be 80% blocked (yet I'd already proved it was flowing huge amounts of water - it just goes to show that your heat-soak issues can be mis-diagnosed when you think the radiator is flowing fine..... when in fact it isnt!)

Specialist guy says "no wonder - your core is not right - it's for a stationary diesel engine" He looks up his catalogue, finds 3 different core applying to Mercedes 350/450/500....

1st core is 3 row parallel (factory), 2nd is a replacement modern 3 row offset, 3rd is a 4 row parallel (factory). He checks the specs of each.

The more modern design 3 row offset core has an 80% efficiency increase over the exact replacement 4 core (4 row parallel which was in the car).

not only that, air flow requirement was less than the 4 core.

Dimensionally the radiator can obviously only use a core that fits within the tank dimensions, otherwise youre talking custom...

After he showed me the old core I was amazed at the blockage - in every single tube! some bad, some completely blocked, some simply hanging in there... it was a tragedy waiting to happen.
He silver brazed the tanks onto the new 3 row offset core and repaired the air bleed line in the header tank, I refitted it to the car.
1st start and it got up to temp quite quickly. I started to get a bit worried I had bigger problems...

But the temp of the car stayed right on thermostat opening temp and never budged - It remained that way over an EVIL summer where we had 45ºC temps for days on end. I thrashed the car and it did not even look like breaking a sweat.
It sat just over 85º and fluctuated the tiniest of amounts. I was rapt.

and to top that off, we discovered a tag on the original radiator core - it was from 1975... so that told me 3 years after purchase, the SLC's radiator was replaced..... STRANGE!! I wonder what caused that.... but not bad for a 42 year old car eh? It was looked after, but you can't predict these things.

So moral of the story is, citric acid flush will only do so much, but you really need to get the radiator checked as well, especially if it's a bit old... And even if the core looks like it flows plenty - silicone worms and other crap can block the cores and cause big trouble. So while it may work for a while, pay attention to the way the temperature behaves when you're not doing highway speeds.

So I learned something valuable about older Mercedes copper radiators... they can hold huge pressure, and they will work perfectly fine, until the heat-soak threshold is reached. They are far more capable of coping with bad cooling systems than any other car I have owned to date....
But it can catch you out - It doesn't have to happen on a hot day... in fact for me it happened on a cool night on the way home from work, well after peak hour traffic...

Once it happens, you simply cannot cool the system down as the heat input is exponentially greater than the heat loss across the core. This is why cars overheat when seemingly 'unloaded' with regards to engine use.
 
#9 ·
Joe,

Thank you for a very informative post - I pulled an entire radiator assembly from a '72 350 SLC in November to keep as a spare. It has the same part numbers as the radiator installed on my car [A 107 501 09 01]. My installed radiator was pulled and flow checked by a reputable radiator shop 3 years ago but I did not get details about rows and offsets. You've got me motivated to take my spare to the radiator guy - have him evaluate the condition and build specs, repair if necessary, then install it and evaluate.

I've been thinking that the A/C condenser sitting in front of the radiator is a problem and that MB did not design the early cooling system with enough overhead to handle the added load of A/C in hot climates - sounds like you've found a solution to this with a 3 row offset core radiator.

I really like the swirl pot flush catch that you discussed. I also appreciate your knowledge of radiator cleaning with zinc chloride. I have a good feeling about the de-oiling and citric acid cleaning of my engine block - I ran a criminal amount of water through it to get it flushed out afterwards. Based on your post, I think my radiator needs a closer look. That 3 row offset rig sounds good.
 
#11 · (Edited)
Joe,

I've been thinking that the A/C condenser sitting in front of the radiator is a problem and that MB did not design the early cooling system with enough overhead to handle the added load of A/C in hot climates - sounds like you've found a solution to this with a 3 row offset core radiator.
Brad,
Understood - hope it was of some assistance - I realize you'd already done the flush, that's not really what I was banging on about - but just a different method when you find some serious junk in the block. You followed the factory procedure and that is exactly how I did my 560, when I replaced the radiator on it back in 2009.

I learned from that time, that one flush was not enough to clean the alloy block, so I did it 3 times. But when it came time to do the SLC, and especially after I had all the strange temp issues, I decided to substitute the radiator, after doing the first flush and then driving around and watching the temp go right up to the 200º mark. So for me, it was a done deal. I wasn't going to waste the extra $ on mb citric acid, and knew I would need bulk amount, so I found a home-bre place nearby and bought 5kg for less than the cost of 500G from MB... heheh

I devised the swirl pot plan and an extended flush, because I had to remove the radiator as part of my diagnostic process. I only made the suggestion here in case someone experiences the same issues in attempting to diagnose their cooling system issues.

Anyway, Like I said, I thought I had the problem licked..... but it turned out that despite all of the rad cleaning (I used progressively more concentrated HCl and ZnCl solutions to try and clean the cores out) and the flow appearing to be absolutely fine, the core itself was 80% blocked - after I cleaned it out.

But the AC condenser is not likely to be contributing much to your problem, unless the cooling fins are caked with junk, causing an almost complete loss of airflow. You can easily clean them though... first remove the aux fan, then you need to spray the core with some heavy duty degreaser and agitate with a brush - like a dustpan brush, following the fins. let it penetrate, and repeat if necessary.

I carefully rinsed mine with a pressure washer - (If doing this you have to be careful, as you can lay the fins over if you hit them at an angle other than straight on) after cleaning with the brush. I already had the radiator out, so it was no big deal. After that I used a compressor to spray air through the core to ensure it was clean. I wouldn't do this procedure with the radiator in though.

Also check a couple of other things. Check the AC pressure switch on the receiver drier, which operates the aux fan is working correctly and also that the temp sender is operating correctly.

That's about all I can think of that could still be contributing to the problem.

The reason I say this, is because my 72SLC was a very early model, with the fluid coupling 4 speed, separate oil cooler and trans cooler in the bottom tank of the 4 row radiator. Prior to observing the rapid change in cooling system performance, the car had done 3 hot summers with very minimal maintenance, giving no trouble.

One thing I will comment on though... is the use of non-genuine coolant.

I'm a bit sceptical about it's use now. I used Zerex G-05 in 3 of my cars, prior to having to completely overhaul cooling systems. The only car I never used it in (the 560SL, Stella) is the only car to never give me trouble with the cooling system. When I purchased that car in 2007, I bought a replacement radiator as it was leaking at the side of the core when I bought the car. I hardly drove it then.. In 2009 citric flushed it, dropped in the new rad, and new hoses. It's been perfectly fine since, only requiring routine maintenance (coolant change and new header tank cap).
Every MB I've used G-05 in, has within several months, required a hefty cooling system overhaul. I'm not implying G-05 is bad - but simply that every system It's been in, has required me to spend a lot more money on, than the car I have used genuine coolant in.

the 16v has caused me the most problems. What is really annoying though, is the fact that until I replaced the coolant with genuine (after the 3rd thermostat housing exploded-) I had problems. Genuine MB coolant was obtained on a saturday (from a damn dealer - $154 for 5 litres... bastards) and it's been a summer, interstate trips and no problems. go figure.... (this is still on my radar...)

The 2.6 had some strange issues with climbing temps. I replaced the thermostat, new header tank and cap and new hoses, did the flush, and it too still had climbing isues in neutral weather. note that the m103's are pretty good when it comes to temp management (201's and 124's are designed pretty well in that regard) but it was not until I changed out the coolant genuine stuff, that the unusual climbing disappeared.

Now this is not anecdotal. I carefully check these things, and I am not sure why the genuine coolant is so much more stable compared to another brand. But when you replace like for like, in a newly overhauled system, and after testing the aftermarket stuff in that system, flushing it and using genuine stuff and seeing the issue go away??? well I'm a sceptical fellow... So I continue to observe.


Bear in mind when I was diagnosing the temp issue in my SLC, I had prior to this, performed the flush, new koblenschmidt water pump, new thermostat & housing, all the hoses, header tank, tank cap, visco fan coupling as well. Tested the senders, tested the gauge... checked everything. Other than a leaking heater core, this was as far as I was prepared to go in my investigation (notwithstanding I did not see any leaking from the trans tunnel, so the core was good in my opinion).

So there you have it. Strange things are afoot at the Circle-K.

I'm still looking for some hard fact that proves what the difference is between MB coolant and G-05. But my hip pocket is saying the cost of the coolant so far, has outweighed the cost of replacing cooling system components in the other cars.

So I'm using genuine coolant. That is the only real difference now.

I can report that when doing the annual fluid flushes, that there is no slime, no white crystals and no discolouration. This is in the m104, the 16v and the 560.
As I no longer have the 201.029 (andrew has that now) and the SLC has gone to live with Craig B, I'm still confident both of those guys are going to have excellent cooling system reliability.

I now do the flush every 2 years on the cars as routine maintenance. Coolant is replaced at 12 month intervals to be on the safe side.

I do not have to remove the radiator... it's just that now I have the swirl pot, I find that is is a good idea to remove the radiator anyway. on the SL it's a 5 minute job. on the 124, it's a 20 minute job. on the 16v flushing the system is a one-day job. (price you pay for owning one).

Maybe I'm a bit OCD when it comes to cooling systems, but I gues anyone else here would be the same if they found out how much it costs in preventative maintenance as opposed to shelling out to replace bits on more than one model mercedes....

aye, there's the rub.
 
#10 ·
The new MB antifreeze is blue in color and requires the system to be flushed when making the change over. I got a can of Liqui Moly which is the recommended flush from Autohauzeaz (sp). The new antifreeze has a -0004 for the last four digits of the part number. The last stuff I bought was -0002. I guess the was a short lived -0003 for a while.
 
#12 ·
Joe,

Copy all - I plan to run this cycle of coolant through the winter and repeat this process next year. My cooling system performance is marginally better so I am certain that my efforts cleaned things up a bit (the green Kool-Aid I spoke of above is evidence of that). Worse than Zerex is the Prestone slime a local indy used when he worked on my A/C system 3 years ago. You've got me thinking now that my recent citric treatment only put a dent in the gunk in my block; good progress but I want to know that I'm running a clean cooling system.

In the meantime, I will source some bulk citric, refit my spare radiator, study the zinc treatment and buy some MB blue anti-freeze - the new spec that Roncallo points out. As for the swirlpot rig you built - any chance you have some pictures of it?
 
#13 ·
I found a good radiator shop today in Albuquerque. The owner, a British fellow - rare in ABQ, was interested in solving the radiator capacity problem. He will clean and test my spare radiator, which is a two row parallel design then make recommendations as to a re-core. He was familiar with the M117 and understood the challenges MB faced exporting to hot climates.

Will report back when I know more
 
#14 ·
Update - I installed my rebuilt spare radiator yesterday. First test drive was in cool weather so it didn't count. Drove it hard today in warm weather with the A/C at full blast. The cooling system works well on the freeway but failed the acid test of a surface street drive (stop and go in traffic) after the freeway. The cooling system is definitely better but I want to improve it.

I will visit the radiator shop again to rebuild my original radiator. The owner had some ideas about a higher capacity core - will report back with whatever we come up with.
 
#15 ·
I will visit the radiator shop again to rebuild my original radiator. The owner had some ideas about a higher capacity core - will report back with whatever we come up with.
When I re-cored The PIG's rad that is what they did. Basically more cooling tubes with a smaller space between them giving more fins blah blah.

I think it increases effectiveness by 25%. Something like that.
 
#17 ·
My original radiator is in the shop for a re-core. I asked shop owner Mike about 3 row offset. He said it would not allow a serpentine fin pattern which outweighs the tube offset benefit. I asked him about aluminum over brass. He explained the industry move to aluminum had more to due with market stability and ease of tooling aluminum and that brass was a good thing in radiators. His idea is more tubes of smaller diameter. "Surface area is everything" was his mantra. He spent lots of time explaining and demonstrating. I like the guy because he seemed genuinely interested my car an in helping me solve this cooling challenge.

This shop's main business is rebuilding radiators from industrial equipment. I watched a team prepping a huge radiator from one of those monster mining trucks from Silver City NM.

If I get it back this week, I may have time to swap it in before a trip to Phoenix for a dash restoration and windshield replacement.
 
#19 ·
I wonder where these guys get their cores from.... I'm sure the one installed in Lurch was an 'off the shelf' part, but I could be wrong.

It seems that the earthmoving guys are the ones to talk to when it comes to radiators. The guys who rebuilt Lurch's were earthmoving guys.

But serpentine fins vs offset? I'm not sure exactly what that means.
I do know the core in Lurch was offset fin and if 'serpentine fin' means fins that weave like an S between each tube, then yes, that is exactly what was installed. Also, those fins had louvres in the actual copper sheet, they weren't just flat sheet.

It's a pity I no longer have the car I should have taken more pics.... I'll ask Craig if he can grab some next time he's down at the shed.
 
#20 ·
Before and after pics.
Yes I will . . . here's the before pictures. Top tank has a pinhole leak in the seam to the core just to the left of the outlet. If you zoom pic 2, you will see crusticles on the tubes - this is a 3 row parallel core. Fins are jacked up; I started straightening them but quit when I decided to re-core the radiator.

Talked to Radiator Mike today - we discussed 2 options for cores and selected the one we thought best for the high desert. He also said he would try to snap some photos of this radiator when it is taken apart so we can see more detail of the condition of the core.

If that happens, we will have pictures before, during and after.

I wonder where these guys get their cores from
I will ask Radiator Mike

But serpentine fins vs offset? I'm not sure exactly what that means
Mike says the offset cores he can source do not have serpentine fins (you imagined correctly - "S" weave fins in between the tubes). He says offset designs have flat fins which led me to believe offset cores were a layered assembly instead of the continuous fins running all the way through the flow channel. He was familiar with offset designs but favored (favoured because he's British) the parallel designs with serpentine fins.

Mike is confident that a new duplicate core would improve cooling due to fresh metal. He further likes the core we chose because it has the added benefit of more tubes.
 

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#21 ·
Re Core of Original Radiator

I got some pictures from the radiator shop this morning. My original core has been removed. The new core with more tubes is ready to be installed.

We just got back from an 1100 mile road trip to Arizona. The spare radiator performed well at highway speeds but gave me some stress in Tucson surface traffic.
 

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#22 ·
Rebuilt Radiator

I got my rebuilt radiator back from the shop today. Shop owner Mike shared some information about the core he installed. Mike's source for this core is a company called Thermal Solutions. Their replacement core is part number 124776 and is able to reject 2983 BTU/min. Mike had them build a custom core for my radiator.

The custom core that is pictured and now installed in my radiator is spec'd to reject 3565 BTU/min. This amounts to a 19.5% increase in capacity. Mike did not have a part number for this core. The new core has 59 rows of tubes spaced approximately 10mm apart. The old radiator had 48 rows spaced approximately 13mm apart. I have new bronze and more tubes so I'm hoping it will perform better.

Albuquerque is cooling off so I won't have a good feel for performance until next summer. I will be in Asia for 3 weeks followed by a very busy work schedule thru Christmas. I don't know when I will have time to install this radiator so an update to this thread be a few months wait.
 

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#23 ·
I installed the custom core radiator last Thursday. I also elected to flush and replenish with the MB blue coolant. It has been in the high 60's all week in ABQ so I don't really have a valid environmental challenge yet. I'm driving to Phoenix next week - that should give me an idea of how this radiator performs.
 
#24 ·
Hey Brad, long time... just got this on an email update.

That core looks exactly like the one in Lurch, which Craig B now has.
I'm pretty sure it's 10mm spacing and staggered rows.
Made a huge difference to mine, but likely to be quite different for you due to climate differences.
I used the OE 79ºC thermostat. I believe you can run as low as 71 without causing the djet to run stupid rich, but it will make cold starting a b****.
 
#25 ·
Joe,

Driving the last two days with lots of attention on the temperature gauge - I have noticed a difference in city traffic and more importantly an ability to recover back to thermostat temp (79C - 175F on the gauge).

If I see this capacity diminish as climate warms up, I will act on your suggestion for a 71C thermostat

Thanks,
 
#26 ·
Brad,
Even over a 3 day heatwave we had I remember the temp gauge sat right on 175ºF and maybe only moved to 190 after I flogged the crap out of it up the pass in 1st/2nd gear - so that was say between 5-8krpm for about 18 minutes or so from the bottom to the top.

it recovered fine and quickly. I found the 79ºC thermostat to be the most efficient for our climate. Your average daily might be a bit higher, but I'm also guessing your night temps drop like a stone, much like they do at my place. So there are pros & cons of using the 71..... if you do find yourself needing it, make sure you really get the rpm's up as soon as you get it started, to avoid overfuelling and fouling plugs... a high idle around 1500 until the thermostat opens. - either doing the blip or just easing it up and dropping back until all systems go.

you know, like flying a DC-10 ... gotta ease it on and roll it off. ;)
 
#27 ·
My verdict is in - this radiator is a big improvement. The acid test was rush hour in Phoenix with the A/C on. The temp did go up slowly in full stop traffic but recovered very quickly to the thermostat temperature if I increased speed to even 30mph.

Coming home, I absolutely blasted up the hill on I-17 to Flagstaff. The temp never increased above the thermostat temp. Last time I did this with the 2 row radiator from the 350 SLC, the temp ran up well above 200.

The only issue I have with heat now is due to low flow from the water pump at idle in hot weather. Normal stop and go at traffic lights is not going to be a problem. A bumper to bumper stop of traffic will be. I wonder if water pumps from later models have more output at idle.

One thing I forgot to mention when I flushed the system this time: I was surprised to see the amount of grit that dropped from the block drains considering how many times I have flushed this system. The right side quit flowing with the plug out because there was so much gunk sitting in the hole. Like last time, I cleared it with a pick. I have the feeling the coolant passages are designed to catch sediment at these points - I think this is a good thing. We'll see if it happens again in two years when I replace the coolant.
 
#28 ·
Great thread!

After all I have tried on my cooling system, I think the best next step is to re-core / replace the radiator and see how that helps.

When I do a search for a replacement radiator, i.e. on AutohausAZ, would this be the correct model number?

Your Parts Search Returned 1 Part(s)

Depending on the cost to re-core, perhaps it would be better to just replace it? I'm also curious to know if this one is higher efficiency than my original? Anyone know if the number of tubes and spacing has changed?

I'm waiting on some quotes and will share which radiator or core replacement is being suggested.
 
#29 ·
Andrew,

That is the correct radiator - spec'd to shed 2983 BTU/min. It will improve the cooling performance in your car due to new metal with no corrosion. I spent about $50 more for the custom build up. It has new metal and more tubes so an improvement of roughly 20%. Nobby did the same thing, so did Joe B.

Having been through this whole shebang, may I suggest looking for a good radiator shop - talk to them about a custom recore on your radiator, then you can make a decision which way to go. I am happy to loan you a provisional radiator that was rodded and boiled out if you go the custom route. That way you can still drive your car while it's being done. If you want, I'll put you in touch with Mike at Independent Radiator here in Albuquerque. If you like what you hear, I'll assist with logistics (PM me about that).
 
#31 ·
Andrew,

That is the correct radiator - spec'd to shed 2983 BTU/min.
Hi Brad,
Old thread but interesting to me seeing I have a pinhole leak in my rad. The rad from AA that Droidster linked was apparently this one: http://redirect.viglink.com/?format...Forum&txt=Your Parts Search Returned 1 Part(s)
That seems to be the one for later models. The original one you said you had was part 1075010901 which is the one I have in my car. Brass tanks. Dealer has them at a price, but nothing at any of the aftermarket shops it seems.

My rad even after 45 years still works fine. But it has a pinhole leak as described in a separate post. I will go talk to our local rad shop and see what they suggest. I probably don't need a performance upgrade given our climate but will see what they say.

Cheers (That harness is still making a difference :) )

Did you retain the oil cooler?
 
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