tigerlam92

TIA:

I have been battling this issues for a year now and been to the dealer about eight times. They have completed all the check such as compression, heads, dye, pressure check on the cooling system overnight, pressure check on the integrity of the IC, etc. Many times, they have found and I did as well no visible leak any where!! They found no problem at all with the motor. For me the car is running strong though. They also did a pressure check on the intercooler as I had requested that and they said that was fine. They have replaced all the small stuff like radiator caps, etc. They also went as far as replacing the water pump since they saw a small leak there using the dye.

The problem is that the check coolant level always come back. Further, they verified and I can see that the coolant level is definitely getting lower. Finally, once every 4 month, I would see a puff of smoke from the tailpipe after the car sits but no smoking on driving or WOT testing.

Any suggestions. I still think it is the IC and won't mind just replacing that with a bigger aftermarket. But I want to make sure it is not the motor. I know the SA and foreman so they have been helpful, but bringing the car in so many times has been a hassle. And although I have extended warranty, they are covering this becuase I have this problem for a long time now and prior to my MB warranty expire.

Thanks for any help or suggestions!!

Only mod is ASP pulley and CM30 IC pump. Dealer helped me replace the crank bolt and vacuum bleed the cooling system.

tigerlam92

Forgot to mention that the amount needed to top it off is maybe 20-30 oz and takes about 1000 miles to trigger the level sensor. This is after it has been top off to the very top of the reservior.

Thanks
Hugh

rflow306

From what you are saying it is most likely the ic core with a small leak.

To rule out a small head gasket issue do a leak down test with the radiator cap off and check for small air bubbles. The pressure test on the coolant system is sometimes not enough pressure to find the problem.

With the leak down test use 120 to 130 psi and you will have to lock the engine to keep it from spinning.

tigerlam92

Thanks. I believe the leak down test was also done and I'm confirming that right now.

Secondly, I think you are right with the IC "core." I am checking if we had pressure checked the IC (110/11 in the picture which is what is in the bumper), or the actual core (110/2) where the cooled coolant is cooling the compressed air before it goes into the motor. I think that is the source of small coolant leak.

Thoughts?




Thanks
--Hugh

AMG Rider

I've dealt with this issue in the past.
It turned out to be that it was leaking from Auxiliary pump(?)...
So, they just replaced it and havent had any problems since then...
I would check that part! just in case...

tigerlam92

Thanks. That part has been checked thoroughly and I'm sure it is not leaking there. I just checked that again too

Updates: Confirmed that dealer had checked the unit on top of the throttle body and found to be sound.

tigerlam92

Just confirmed that a leak down test was completed as well.

Vadim @ FD

Most likely it is IC core. C32s and SLK32s have gone through this problem as well.

One way to check is to have dealer remove one of the surge tanks, it has AMG lettering on it, and check for coolant residue inside. It will take less than an hour to do.

Good Luck!

tigerlam92

Thanks Vadim. Maybe I will re-check this myself.

tigerlam92

I pulled both surge tanks to check, they are both clean except for some oil residue as the dealer told me. I have pictures that I can post later if people are interested.
Nothing at all like - https://mbworld.org/forums/showpost....2&postcount=41

Any other ideas? Would this mean that it may be a head gasket? All previous head gasket tests had passed at the dealer.

Anyone else need to top off coolant every 1000 miles?

Jakpro1

Long shot, but we have had reports of coolant getting into tranny through cross contamination through radiator.

https://mbworld.org/forums/showthrea...t+transmission

Yacht Master

This my friend is the key 30 OZ per 1000 miles say a month so 1 oz a day right. That is a pin hole in the IC, not enough to detect down stream in the surge tanks cause it only leaks under pressure when the engine is running. hot coolant @ 15 PSI passing through a porous weldment ready to go vapor.
You can pressure test it till you turn blue it wont leak cold.
A head gasket would have manifested in a much larger way by now.
First move when you have a coolant loss, check for external leaks. second move test the oil for coolant contamination. High levels of coolant in the oil are cracked block, cracked cylinder, blown head gasket, cracked head. Low levels of oil contamination almost always an intercooler.

tigerlam92

Thanks Jakpro1. I will ask dealer about the radiator leaking into the tranny. I had read that before, but that is usually easily detected so I don't think is the problem.

Yacht Master: My thought is exactly the same. I have always thought that it is a pin hole in the IC core that shows itself under high pressure and doesn't leave residue behind.

OzE55

After all those dealer visits and tests you should be able to convince them to change the IC - its gotta be cheaper all round!