Need urgent help please - Oil in Coolant Reservoir 2003 C32 AMG Eurocharged Stage 3
Last edited by Elideli; Jan 5, 2018 at 01:10 PM.
When returning to home, I opened the hood and suddenly I saw a little of fume coming out from where the coolant reservoir is located. And it smelled the exact same odour as I have smelled many times in the cabin when the car was on idle. It was coolant that was evaporating. I went straight to see and saw indeed some coolant sitting under the reservoir. I have attached video for you to see. Could all this headache be due to a cracked hose coming from the coolant reservoir? I’m having this issue since six months, never lost power, never had misfire, I only lose coolant all the time. I’m sure it’s nothing major but I need to get this fixed once and for all.
edit: I could not attach the video but I have uploaded it to Dropbox: https://www.dropbox.com/s/k9akpo36us...%20PM.mov?dl=0
Last edited by Elideli; Jan 5, 2018 at 05:16 PM.
So you checked the intake plenums? is there coolant caked up there? The common place for coolant leaks is the intercooler aka "Charge Air Cooler 110/2", NOT the heat exchanger. That is what most people end up replacing.
If you do end up replacing it, do not get an OEM one, get the aftermarket one from Speedriven. Unfortunately, I see that their website is no longer up but I see they have a FB page. I also see they are listed as "Banned" from MB World.
I replaced my leaking intercooler with a New OEM one and it leaked agin in over a year. I have the aftermarket one and no issues for 4+ years.
OEM heat exchanger with your mods is going to take longer to recover from heatsoak, so you will have loss of power once hard on the throttle.
So you checked the intake plenums? is there coolant caked up there? The common place for coolant leaks is the intercooler aka "Charge Air Cooler 110/2", NOT the heat exchanger. That is what most people end up replacing.
If you do end up replacing it, do not get an OEM one, get the aftermarket one from Speedriven. Unfortunately, I see that their website is no longer up but I see they have a FB page. I also see they are listed as "Banned" from MB World.
I replaced my leaking intercooler with a New OEM one and it leaked agin in over a year. I have the aftermarket one and no issues for 4+ years.
OEM heat exchanger with your mods is going to take longer to recover from heatsoak, so you will have loss of power once hard on the throttle.
The coolant you see on top was from before when I opened the reservoir while it was a bit hot. The car never overheated. It can’t be a blown headgasket, there is no white smoke, the oil cap has no milky substance, and the car never misfired. I always make sure the engine temperature is what I see on my dashboard while I drive the car and it always run at 90 degrees with normal driving and never went up 100 degrees when driven hard. All this knowing that its been almost a year and 7K miles since this mysterious coolant loss appeared. I would assume that if it was a head gasket, things would have gotten worse since then.
I have just placed some white paper under the car where the coolant reservoir is located, I’ll see tomorrow if there any drop/puddle.
Other issue could be simply coming from the radiator which would be tested on Monday.
Last edited by Elideli; Jan 5, 2018 at 11:13 PM.




Get your mechanic to pull an intake plenum on one side and look for coolant ‘slime’ inside. If any is found, replace the charge air cooler as described above with any model except OEM. I replaced mine after finding the slime and have had smooth sailing since then.
Keep us posted on the outcome.
Get your mechanic to pull an intake plenum on one side and look for coolant ‘slime’ inside. If any is found, replace the charge air cooler as described above with any model except OEM. I replaced mine after finding the slime and have had smooth sailing since then.
Keep us posted on the outcome.
Those little squared/rectangular crimps are an indication that you have a Valeo radiator. You can see them on the top right of your rad from the drivers side.
Now the question is what are thare symptoms of a failed transmission coming from a failed Valeo rad? I have to drive back Monday to the shop and it’s about 5km, is there any risk? Is there a procedure to explain how to conduct a glycol test? Or can I just go ahead and replace the transmission fluid completely?
Last edited by Elideli; Jan 6, 2018 at 06:05 PM.




Call any transmission shop or your mechanic and ask him how to test for glycol. If any is found, swap the radiator, and trans fluid and filter.
edit -looks like a simple test strip for glycol: http://www.acustrip.com/cgi-bin/prod...gi?s=ACU711254
Changing the fluid will help, but it will be contaminated again in minutes. Good luck.
Last edited by kbob999; Jan 6, 2018 at 07:16 PM. Reason: added test link
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Call any transmission shop or your mechanic and ask him how to test for glycol. If any is found, swap the radiator, and trans fluid and filter.
edit -looks like a simple test strip for glycol: http://www.acustrip.com/cgi-bin/prod...gi?s=ACU711254
Changing the fluid will help, but it will be contaminated again in minutes. Good luck.
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The 722.6 trans is very popular for MB and flushing the torque converter requires unhooking a fluid line if I recall.


