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Oh to be cool again

5K views 71 replies 13 participants last post by  MJSb 
#1 ·
AC on a 99 E 320

Replaced the AC compressor, drier, expansion valve and pressure switch. Took awhile would never had been able to do any of it except for this site.

Had the system bled out and there e was not much refrigerant in the system.

Then took off everything on the wiper / water catch system cleaned a million leaves out. Flushed the system, doing the evaporator and the condenser as well as the lines. Replaced the expansion valve and repaired some of the wiring in the trough area below the windshield. Took off the compressor (a chore on its own) remounted the new one and then completed the drier, (the pressure switch had not arrived). Vacuum checked the system and then reassembled the wipers and the lower body kit. All in all it took about 8 solid hours and a lot of prep work. Once the pressure switch arrives I'll charge the system with R134a and it should be nice and cool again.
 
#4 · (Edited)
I do not think he ever said he replaced the evaporator core. I read it he flushed the system which included the condenser and the evaporator.

He replaced the expansion valve which is accessible under the windshield.

And the question arises, why the compressor / expansion valve were needed to be replaced ?
 
#11 ·
I see.. Mine has a very small leak (not sure where). 3 years ago, I put about 8 ounces of refrigerant, and still cooling as it should. My "method" of checking is after the system is settled at the coolest setting, I look at the left/right heater core and evaporator sensor readings using the hidden menu. If the heater sensors are within 1 degree C of each other, that is good enough for me. Of course the evaporator sensor should be able to come down within few degrees above the freezing point.
 
#12 ·
Similar problems with Ac not cold when getting into the vehicle or until I got to my 10 mile work destination, get back in the car and AC works, the clutch every so often made a slight high pith sound when attempting to engage, I ran the diagnostics on the control unit and a most every code was off the chart, I am just one of those guys that if the units not functioning I replace everything about the issue. On a 18 year old car it never seems to be the little stuff. And after I got into the system it was apparent that visitors had been there prior, as I am the second owner of the vehicle.
 
#17 ·
If you have good compressor already - you can buy Venturi pump for like $25, the gauges on HF sale are about 50, than you can buy 30 lb of R134 for another $40 and you are set for life with AC servicing.
BTW my $6000 refrigerator was low on charge couple years ago. Guess what refrigerant it used?
 
#18 ·
And Kaj, out of curiosity, how did you know the fridge was low on refrigerant and how did you know how much to put in ? If it is a $6,000 fridge, does it have a hidden menu ? :)

I hope my home a/c does not quit on me. It has the R22 in it, so you can guess how old it its. But it works !!!!
 
#19 · (Edited)
each compressor has label on it telling what refrigerant it is using. You know it needs charge when ice cream melts ;)
Mine has temperature display, what help.
I found some videos on youtube how to recharge household fridge.
First you have to install shrader valve, what cost about $5.
Than unlikely car system, the fridge works mostly on vapor, meaning it was still cooling while suction did show good vacuum.
Fridge also is having much smaller passage, so you have to charge it with vapor and be very patient especially with inverter compressor like I had.
I don't have the precision scale, so charged it to 5 psi and confirmed next day it is staying there. I think it took less than 6 oz.
 
#20 ·
Asked for answers from Temp Control Unit: None

Final valve came in yesterday and installed today, Before doing anything else, I went back over everything I had touched as far as AC, reread everything, one of the PDF files noted to add 20 ml of pan oil to compressor as the system had been flushed. I did and put dye in the system. Ran a vacuum on the car to -30 mercury and then closed system and waited an hour gauges never moved. I went and restarted vacuum pump and ran for another hour, shut it off, closed all valves.
Began installation of refrigerant, slow go on 1 & 2 and on 3rd checked weight to make sure I had 33 oz total, temp gauge in car was still in mid 50's at center outlet, let the car run about 10 minutes more and then shut it off.
All hell broke loose, then: lost all refrigerant, dye and probably oil. It was coming out at the compressor, could not tell if it was high or low, I wasn't sticking my head into that mist. washed the area down restarted car and not a lot of dye to be seen.
So I sit hot and ready to go do it all over again or ?

So any help now is REALLY APPRECIATED.

Mike Smith
99 E320
 
#21 ·
If I could offer my opinion and advice, may I suggest you take your car to a competent mechanic who is familiar with the MB air conditioning systems ?

You have done most of the work, and it should not cost a lot for a technician to check your system over prior to recharge. The reason why I am suggesting this is, possible risk of serious injury, if you are not absolutely sure of what you are doing. You may get hints, DIYs, advice, from here and there, however we cannot know what you have done so far, how much oil had been added, what valves you have just changed, so it is best if the system is checked over by a professional who physically can examine and fix any problems your replacement project may have.

Please be safe...
 
#22 ·
I am one of those who never give up.
Now that the mist come down, you should be able to easy pinpoint the break.
If not - sacrificing a bit more of refrigerant will easy tell.
Even compressed air will do, but then you will have to worry about moisture contamination

 
#23 ·
For what its worth, last compressor I changed on my E300TD had a dedicated oil hole specifically for the compressor oil. You do add some oil in the refrigrant, but also the same amount in the compressor oil fill...you remove one bolt somewhere, i forgot, and then add oil, reinstall. Best done with compressor outside, since stuff will be in the way while installed.
 
#25 ·
The problem is finding one you can trust.

I'm one of those people who is (almost) always dissatisfied with the professional services I purchase. Whether it's carpet cleaning (they left their dryer fan on my porch for a week and made some spots worse), car alignment (greasy steering wheel), A/C work (grounded a wire that should have been connected to hot, frying a harness), "detail" of my car after bodywork left bondo dust everywhere ("detailing" in Seattle is not even as comprehensive as a plain wash & wax in LA), injection pump rebuild (CC disconnected, idle too high, manifold clamps left off, and a month later a cracked IP housing that I had to threaten corporate to get fixed at 35 days after repair), it's always something not done well or collateral damage.

After decades of poor service I find I'm happier doing EVERYTHING myself. At least when I break or damage something I know I did my best. I have not had success paying others to give a damn about my stuff.
 
#26 · (Edited)
I am like Al. >>>> DIY >>> DIY>>> DIY
Even my electronic skills are poor, I have successfully repair some electronic items (with help of my neighbor giving me advise)
With MB there is huge learning curve.
Even W210 are turning 20 YO, the knowledge about electronic AC between AC specialist is very poor.
Most systems they know are operating on on/off switches, so taking MB to them is like asking basic electrician to troubleshoot WI-FI dimmer switch.
One of members tried to service his 7-sp transmission. Even those are turning 10 YO - his local dealer had no clue they fill up by bottom fill and had no idea where he could buy necessary hose adapter.
You need new technology serviced, you are forced to DIY.
On other hand, even we don't talk about our education, it is WAY higher than average automotive technician. We might not have practical experience, but we can brainstorm the problem.
 
#27 ·
Nothing wrong with DIY, if you have time, knowledge, proper equipment, desire, ability, and good liability insurance:).

Bear in mind that we have members who are well into their 70's and 80's who follow these threads. One would not expect them to go under a car (provided that they have the proper jackstands / ramps), replace a transmission adapter, or drop the valve body to replace the conductor plate). Few still can do, but the majority will take the car to a workshop (as they should, due to risk of injury, especially if they had never done these repairs themselves.

Of course, it is important to make sure the workshop has the knowledge, equipment, experience to work on MB cars, and to find a good workshop, one is encouraged to check out the "recommended repair shops" thread complied per region / city.

After my gardener let me down by not turning up, I started to mow my own lawn. That is OK, it is a relatively low-risk job, with low cost investment in a good lawn mower, and I do a satisfactory job of mowing, edging etc. However, when I need my roof pressure cleaned, that is a job for a pro. I do not have the right equipment, skill to walk over tiles without breaking them, patience, and experience. And of course, the risks of falling with serious injury, and even death are much higher. So a few hundred dollars for a pro to take the risk and do the job is well-worth it to me.

In my opinion, there are certain car repairs that should be left to competent professionals, especially when the risk of personal injury, and injury to the others (passengers, other drivers, pedestrians, etc.) are high, when the repair-work is not properly done.
 
#28 ·
My father is 92 and last week he was repairing fallen retaining wall in his garden.
By touch as he is about 80% blind. ;)
He "was" forced to DIY as last month he hired gardeners for 1-time help and they broke big patio door on his veranda, what turned out to be huge hassle to repair.
The gardeners deny any responsibility.
I do age and discovering physical limitation sucks, but then you have technology coming to help.
Very few things on MB require crawling under the car, but I already check that I can buy 4-post lift for $2200 NEW + $200 delivery cost.
It is free-standing and coming with wheels for rolling around.
Once I get my stuff from California, that is my next project.
 
#30 ·
Now that the pressure valve came in and some other parts the system is back together and pushing cooler air, not cold but cool.

Ran the DTC tests had only 1 error
B1232 Refrigerant Pressure Switch, this had been replaced so I cleared it and then ran the car for about 5 to 6 minutes and the temperature was coming down but seemed to hold at 65

When I ran AC Diagnostics I ran 3 different tests
Test 1 Test 2 Test 3
1 71 76 75
2 82 98 84
3 75 76 143
4 73 75 94
5 109 109 107
6 199 208 213
7 11 11 07
8 132 130 127
9 27 30 27
10 6.0 6.0 6.0
11 2.8 2.6 2.7
12 4.1 4.2 4.3
20 3.2 3.2 3.2
21 32 32 32
22 00 0 0
23 32 32 32
24 11.3 11.3 11.3
40 164
41 85
42 104
43 152

system has been charged with R 134 A @ 34 oz
Pressure on gauges 30 to 42 low side
high side 150 to 210

Cleared all error codes

Temperature on center vent Drivers side 75 passenger side 62

So now i am still not completely satisfied any help or thoughts.
 
#33 ·
Now that the pressure valve came in and some other parts the system is back together and pushing cooler air, not cold but cool.

Ran the DTC tests had only 1 error
B1232 Refrigerant Pressure Switch, this had been replaced so I cleared it and then ran the car for about 5 to 6 minutes and the temperature was coming down but seemed to hold at 65

When I ran AC Diagnostics I ran 3 different tests
Test 1 Test 2 Test 3
1 71 76 75
2 82 98 84
3 75 76 143 Left duo valve not sealing
4 73 75 94 Right duo valve not sealing
5 109 109 107 Sensor stuck
6 199 208 213 Engine temperature too high. What is cluster showing?
7 11 11 07 Was compressor running in test 3?
8 132 130 127
9 27 30 27
10 6.0 6.0 6.0
11 2.8 2.6 2.7
12 4.1 4.2 4.3
20 3.2 3.2 3.2
21 32 32 32 Why is engine at 3200 rpm?
22 00 0 0
23 32 32 32
24 11.3 11.3 11.3 Alternator charging?
40 164
41 85
42 104
43 152

system has been charged with R 134 A @ 34 oz
Pressure on gauges 30 to 42 low side
high side 150 to 210

Cleared all error codes

Temperature on center vent Drivers side 75 passenger side 62

So now i am still not completely satisfied any help or thoughts.
Those values don't add up at all. Connect battery charger. Before sun comes up read actual values again. Key on, engine off. 1234568 need to be equal (+/- 2).
 
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