NitrogenBalance

Just thought I'd let yall know. You may want to check around the lower part of the oil cooler to see if any oil is there. It's part of the oil filter housing. It drips onto the belt and pulleys and makes a mess. Mine is pretty steady.

There are two small ring gaskets oval and round. About the size of a quarter each and cost $25.00 each!!!LOL.

If small the leak could go unoticed for a while so I thought I would let all know in case its a C43 common issue. Use an extendable small auto mirror and you can see around pretty good. Look on the bottom of it obviously.

I'll post pictures when it's apart if anyone needs a DIY.

SDR

Thanks for the heads up. As these cars age we should all keep one another updated on these types of issues.

C43AMG

Please post some pics when you can, thanx !

NitrogenBalance

Here are the pics of the oil cooler repair. I didn't enjoy the process. It was kinda tricky working around the tight areas as any C43 owner would know

First thing was to drain the coolant and remove the yellow arrow stuff including the coolant hoses (1)large to radiator (2) feeding bottom inlets of the oil cooler held on by crimp style hose clamps. You need long reach needle nose to get to these. There are also four corner located torx bolts holding it on.


Here you can see the lower coolant lines contected to the oil cooler. I pluged the lines up so nothing could fall in there as I'm sure it would have.


Here the coolant lines are in blue with a dashed line showing the larger one removed. The red arrows are the older gaskets which appeared to the human eye to be fine once I removed them.


Things all cleaned up. The new gaskets cost $38!! for that much little rubber. They are a tiny mm thicker than flush. They flatten out and form a seal once the cooler is tighted down. Heres the kicker!! The tiny leak was still there once I finished!!! I'm thinking that the cooler itself or the filter case is no longer straight by a hairline. I repeated the process and added a tiny bead of high temp gasket seal around the outer edge of the gaskets to form an additional seal. Use the outer edge as to prevent any sealant from getting into the oil. I think that a flat gasket the shape of the cooler face would be a better design like a head gasket material. It would be a small sheet.Two holes cut out for the oil flow.


All done. No hint of leak after a week or so of driving...knock on wood.

hy-rail benz

nice pics, and good post. hope my oil cooler doesn't develop a leak, it looks like a ***** to getin there. good luck with the fix, let us know if the extra gasket sealant did the trick.

Vardar

I sincerely appreciate that you took your time to take pics. and clear explanation. Thank you

C43AMG

Great write-up and fantastic pics! Stupid question but I have to ask - Did you try torqueing everything to spec BEFORE you took on the task of replacing the gaskets.I just wonder that MAYBE, over the course of 8 years , they had loosened up?

NitrogenBalance

I did try to tighten them up a bit more. The leak was still there and I felt that if I torqued them any more it could be a bad thing, stripping, snapping, etc...

I hope to tackle the wheel bearing(if thats the prob) this wednesday.

Anyone know of any odd size tools or things needed for the bearing replacement.......

fastneutron

Nice post. I have exactly the same problem, which I thought the leak was coming again from the front crank cover. I've had this leak for a while and let it go. Last night, the drive belt broke, which I just replaced 20,000 miles ago. It's probably due to oil constantly leaking on the belt.

This happened right after seeing another C43 at Claim Jumper in Valencia, CA and chatting a little bit with the owner.

A supposedly early weekend turned into a very late repair in the parking lot. I also realized that the spare belt I had was the stock belt. I actually needed something that was 1 inch longer since I have the EVO sport pulleys.

Anyhow, back on the road and the next repair is definitely the oil cooler leak.

Thanks again for the post. This will be my next weekend project.

NitrogenBalance

Buy some high temp RVT sealant as well. Put a very small bead around the rubber gaskets outside edge before reasembling. Also, a hairline bead in the channel that the rubber gaskets sit. Not to much and none on the inside gasket edges as you don't want sealant being picked up in the hot oil stream. My tech recomended this because he told me that the surfaces may not be 100% flat over time and the OEM gaskets won't spread or flatten enough to make a seal. Tighten the bolts down in a pattern like you would a wheel.

Lastly, I should have removed my fan for easier access. It would have saved an hour from dropping and trying to reach things.

StapleGun

Great post 'Nitro' - I'm sure it's just a matter of time before I tackle this one.

NitrogenBalance

Found this, for who ever was looking for this info today.

sgort2

what did you find?

myc43amg

I had this same problem last month. I posted here somewhere as to how to fix this without going through all........... you need to tighten the left and right BOTTOM bolts on the cooler real tight. they will not break or strip, just dont use a HUGE wrench. I used the small 1/4 drive. the problem is the screws do get loose (or mb loosens them when our cars are serviced,just a theory) and oil leaks. specially the screw near the block, that one really needs to be re-tighten. after the work which took less than 1 minute the leak is gone. i been driving it hars too just to make sure.

sgort2

Check out the post "C43 leaking oil.. likely spot?" and look at the photo I posted toward the end of the thread....

Is that 2 bolt plate the engine timing cover? That's what's leaking on mine not the oil cooler, I just want to make sure I order the right seal, thanks.

ProjectC55

Excellent post Nitro,guess I will tackle this problem before I actually install this stupid idler pulley.


I believe that this is why my serpentine belt got damaged which also ruined my idler pulley in the process. Belt had at least 20 k miles which was chgd brand new when I had the 5.4L motor dropped in.

ProjectC55

Or maybe I will try this first!

ProjectC55

After takingt this cooler off the engine I am definitely going to replace both gaskets. I removed everything,fan,radiator,it just makes the job that much more easier for you to spray and clean ALL the gunk off the motor ,especially in hidden places like behind the steering pump pulley and areas like that.

Well I know one dealer has two of the three gaskets I need,hopefully I can have my car back on the road by this Mon., the latest.

PJmak

Nice thanks a lot man



Noticed a small leak under my car and was looking into that area in my engine bay today. Thats exactly what I thought it was



Thanks for the write up

NitrogenBalance

so what did we pay for the quarter sized rubber gaskets...? $$

ProjectC55

Dude! I was shocked!

Damn gaskets cost me like 30.00 a piece. 63.00 total.! I can't believe it. They look like regular rubber gaskets to me. Or something I could have made with the factory black rtv sealant used to seal the oil pan to the block.

Talk about robbery! Jeez!

Well at least I also got to see a SL65 Black Series on the show room floor. Incredible. sticker price: 300k

rondocap

These oil cooler leaks are common, I have an S55 AMG and had the same problem - it's good to get fixed because it can leak onto the belt and cause it to slip out or snap if it gets too saturated.

ProjectC55

Did you read the beginning of this thread?

Rue-Sant Angel6

bump my brothah!

KJI3jflarryfe93

when you removed the hoses I noticed you have removed the oilfilter, was that b/coz you were going to make an oilchange?
or was that just for easier axess when putting the new gaskets in place on the oilcooler sidewall?

Did you have to drain the engine from oil before you began removing all hoses, to prevent oil pressure leaks where those bad gaskets are placed?

Did you also change the front squared timing case gasket?
these gaskets come in 2 different versions,
old style is only a square rectangular shaped gasket,
and the revised gasket is squared rectangular with a centre piece rubber which is better.
Early C43's had the first inferior gasket, and later had the revised.
How can the engine serial number be checked knowing which gasket is on the engine?
Autohausaz lists each gasket up to a certain engine serial number.