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2000 E 320 Wagon + 2002 ML 500 SUV
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Discussion Starter #1
Hi Guys:

I'm hoping to pull any of you who've had an ML radiator fail where the side tank (plastic) to (aluminum) core seam seal is ?

I've got a modest leak that I believe is there. All hoses are tight and a drip forms at very bottom of Drivers side radiator edge.

If I just relieve pressure by loosening reservoir cap for a moment after each drive, then dripping only a few drops.

Additionally no coolant is lost while driving.

It's only dripping out maybe 4 to 6 ounces when I stop driving & shut down WITHOUT releasing pressure from coolant reservoir, but eventually stops.

I'm not thinking of using any stop leak solutions (big no-no) but am hoping it's safe from a catastrophic fail as I'm some distance from my "home 20" shop with all my tools, and am hoping it's safe to travel back home.

If anyone has any insight or experience on this it would be helpful !

David (not currently) in Texas
 

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w163 02 ML500 W210 97 E50Amg w202 99 C230K w124 - need more space, time to build again
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2,222 Posts
Hi Guys:

I'm hoping to pull any of you who've had an ML radiator fail where the side tank (plastic) to (aluminum) core seam seal is ?

I've got a modest leak that I believe is there. All hoses are tight and a drip forms at very bottom of Drivers side radiator edge.

If I just relieve pressure by loosening reservoir cap for a moment after each drive, then dripping only a few drops.

Additionally no coolant is lost while driving.

It's only dripping out maybe 4 to 6 ounces when I stop driving & shut down WITHOUT releasing pressure from coolant reservoir, but eventually stops.

I'm not thinking of using any stop leak solutions (big no-no) but am hoping it's safe from a catastrophic fail as I'm some distance from my "home 20" shop with all my tools, and am hoping it's safe to travel back home.

If anyone has any insight or experience on this it would be helpful !

David (not currently) in Texas
Hi David,

Had a very small drip drop leak on the DS of the radiator at the plastic metal seam and monitored it for several months last year in June 2018. Like your situation, not enough to lose coolant to refill. It only dripped leak (from what I could see) after we parked or returned home. Placed a cardboard piece directly below the seam location to monitor it. Watched it for 3 months knowing I would eventually need to replace the radiator. I did not relieve the pressure at all - just monitored it. We drove an easy 2000kms monitoring it until I finally decided to replace it with one from Amazon finds ($100 bucks) and my time. When I looked closer at the one pulled out, I could see hairline surface cracks along the joint on the plastic, DS. No leakage along these cracks though The small leakage was occurring higher up the seam on the radiator and bleeding thru, only wet enough (in our situation) the run slowly down the length of the seam. At the end of a days drive, we only had 'not even 1/2 a thimble full' of coolant on the cardboard that rested below. Sitting cold, nothing, no evidence of persistent leaking on the cardboard.
When I did finally replace it, fgave me a good reason to flush the entire system.
For us, no catastrophic failure.
 

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2000 E 320 Wagon + 2002 ML 500 SUV
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Discussion Starter #3
Super to hear your account Khomer.

I can only hope my radiator is able to hold out similarly.

Especially as I'm 850m from home in Indianapolis thru next weekend, and pulling a small 12' cargo trailer as well.

I'm wondering if they all "fail" in such a generously relaxed manner or if I should be more concerned ?
 

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2001 ML430 230K Miles
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89 Posts
Hey Dave,
I drove mine for quite awhile before replacing the radiator as I assumed it was just a hose leaking. The drip came and went and was never really that bad. Seemed to leak only went hot (expanded)and seemed to stop when it cooled down(contracted).
Can't really say if it will leave you stranded, it seems to have sorted itself in a way by releiving its own pressure with the split and with the cap loose, pressure wont really build anyway.
Thankfully there is a real temp guage to keep an close eye on it!

Good luck buddy!

Sent from my VS988 using Tapatalk
 

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2000 ML55 sold😢 2013 ML500,😁 2015 C250 estate wagon, 1927 Dodge 4 sedan, 1929 Dodge
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4,742 Posts
Sorry to be the bearer of bad news but I didn’t even see a leak in mine and after I went for a short drive and pulled up at work, it basically exploded at the top hose and sprayed coolant everywhere. The plastic had just split. There was a lot of steam coming from every corner of the bonnet.


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1998 e430
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375 Posts
on my '98 e430, no evidence of any leaks until we parked in the garage after dinner. went out an hour or two later to find a medium pizza sized puddle of coolant under the car. it was coming from a 4-5" crack near the upper hose.

i'd say the risk of getting stranded on your way home is very real...
 

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2000 E 320 Wagon + 2002 ML 500 SUV
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Discussion Starter #7
Ok great to hear all your experiences !
2 went gently & 2 not so much !

It will be a lower temperature winter trip perhaps that's in our favor.

Can anyone say what the effect of driving with the cap slightly loosened (to keep pressure lower) would be ?

Beneficial in any way?
 

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2002 ML 320 Sport
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10 Posts
I had this same issue with a small leak at the same location you indicated and drove it for over a year simply topping up the coolant when needed. One issue is that that secondary coolant pump continues to run for about five minutes after the engine is shut off and that is when much more coolant would leak out. Gets old having to unscrew the coolant cap to release pressure and carrying extra coolant. Replaced the radiator months past (pretty easy DIY) and now she's dry as a bone.
 

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w163 02 ML500 W210 97 E50Amg w202 99 C230K w124 - need more space, time to build again
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Ok great to hear all your experiences !
2 went gently & 2 not so much !

It will be a lower temperature winter trip perhaps that's in our favor.

Can anyone say what the effect of driving with the cap slightly loosened (to keep pressure lower) would be ?

Beneficial in any way?
Colder outside temps will certainly help.
Not sure about the rad cap idea, although I dont think it would hurt (just monitor it?)
 

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2000 E 320 Wagon + 2002 ML 500 SUV
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Discussion Starter #10
Very helpful, thanks to you all !

I have the new Mahle-Behr radiator on the way from fcpeuro.com

That way I've got it on hand for the trip home !

I plan to locate a DIY that lists all the tools needed for the job, just in case.

I've got a tool set with me but it probably lacks something needed, right ?

- Regards - David, currently in Indy
 

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2002 ML 320 Sport
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10 Posts
As I replaced the radiator last Nov. the only hang up was dealing with the AC bottle. It has a plastic collar around it that requires a small female torque socket. Sorry I don't recall the exact size but essentially you just want to loosen the collar and work the bottle out of the way and then slip it back in when the new radiator is installed. A second set of hands does help and remember all the rubber grommets from the old radiator need to be removed and put back on the new unit. Good choice to replace, you'll be pleased with the results.
 

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2000 E 320 Wagon + 2002 ML 500 SUV
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Discussion Starter #12 (Edited)
Klaus,

Do you mean this part ?

2617859
open-uri20170126-7343-sgzl18.jpg


How many are there ?

Are there top & bottom ones ?

I didn't order but probably should have.

Are they normally trashed by this time ?

Thx David
 

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2003 C320 coupe, 2000 ML320
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678 Posts
You can drive with your cap loose, which is good because of "no pressure".. but run the risk of boiling off all your coolant. Being winter and low temps.. the risk of boil off are low.. You just got to keep an eye on it.. I drove once over a 1000 miles cross country with a spit in my block (water jacket).. Took the cap off, jammed a 2ft piece of hose down in the radiator filler neck, then stuffed an old t-shirt in the neck with the hose.. ran the hose out over the top of the hood.. So I could see when my water started to turn to steam.. At such time, I'd pull over and filler it back up.. .
 

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2000 E 320 Wagon + 2002 ML 500 SUV
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Discussion Starter #14
You can drive with your cap loose, which is good because of "no pressure".. but run the risk of boiling off all your coolant. Being winter and low temps.. the risk of boil off are low.. You just got to keep an eye on it.. I drove once over a 1000 miles cross country with a spit in my block (water jacket).. Took the cap off, jammed a 2ft piece of hose down in the radiator filler neck, then stuffed an old t-shirt in the neck with the hose.. ran the hose out over the top of the hood.. So I could see when my water started to turn to steam.. At such time, I'd pull over and filler it back up.. .
Wow, Bobby thats crazy, but it worked, eh ?

Good to know. As it was, the leak stopped once I started doing the 'loosen cap after driving' routine.

But, I have a new radiator just the same, will install it shortly.

Thanks for all the help & replies !

David
 

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2003 C320 coupe, 2000 ML320
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Ya, it was a 63' Nova.. inline 6.. 3 on the column.. The split was from the front of the block all the way to the back.. Took some of that old t-shirt, jammed into the crack.. Hammered in some wood chips to hold the t-shirt in.. Chicago to Miami in 18 hrs.. I think I drove the old Nova straight to the junk yard once I got home.. Got $50 bucks for it.. And it was still running fine, accept it couldn't hold any water.. o_O
 

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Discussion Starter #16
Wow, Bobby thats crazy, but it worked, eh ?

Good to know. As it was, the leak stopped once I started doing the 'loosen cap after driving' routine.

But, I have a new radiator just the same, will install it shortly.

Thanks for all the help & replies !

David

Well just for the record, I finally replaced the 'seeping' radiator - thank the LORD we made it home fine (kind of, something else gave way) but the radiator still held out, not consuming any coolant on the way.

It continued to seep at the same rate, only loosing coolant when I ran it to hot, then didn't release pressure by loosening cap upon stopping. If I didn't, it would leak out maybe 4-6 ounces average each time. Not dangerous, but it depletes the coolant reservoir steadily.

So, we installed w163 ML500 radiator by BEHR - $ 115 at www.fcpeuro.com and the install was tedious but not hard. Trickiest part was helped by my son, you have to twist & angle the radiator carefully past the AC Condenser & receiver tubing (those are not disconnected or removed).

Now, there are no leaks whatsover the coolant level is totally constant. Nice feeling !

Cheers - David in Texas
 
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