bullitt69

The car was in very good shape in all other aspects, the MB dealer told me it wouldn't be anything serious so I decided to purchase the car.

It is a used 6 year old car, so I was expecting that I'll need to invest some money into bringing it to ideal shape.

bullitt69

I really hope I don't have the same problem as the one described in the following thread:

https://mbworld.org/forums/c63-amg-w204/439178-2010-c63-p31-porous-aluminum-head-leak-bottom-plate-bad-head-bolts.html

Jasonoff

That's the upper oil pan (where I suggested in my first post). I'm not sure if it's really necessary to remove the engine to fix that.

bullitt69

I think it really is necessary as you can't remove the upper lower pan without pulling the engine.

The photo at the end of the first page of the thread where a guy is pointing at the place of the leak with a pen is really close to the place where the engine mount bracket is.

It could also explain why motor oil leaked out when my mechanic screwed out the engine mount bracket bolt. Oil could have accumulated in the cavity behind the bracket.

If that is all true it's really a shame, I don't really want to have my engine disassembled 2 months after buying the car.

On the other hand, I haven't noticed my car losing any oil. Maybe some oil stop leak additive can remedy the situation?

Jasonoff

Find out where it's leaking first and don't put stop leak in.

If it's leaking from a small spot you may not need to remove the pan to fix it.

bullitt69

you mean external repair is possible? It would be difficult to clean oil off prior to filling the gap with any solution

Jasonoff

Tons of options. Maybe something like this will work.

https://www.permatex.com/products/ad...t-leak-repair/

bullitt69

thank you for the link!

bullitt69

Anyways guys, oil was leaking from one of the engine mount bracket bolt holes in the lower oil pan.

It seems that it's a production flaw as these holes aren't supposed to be through. We just like some sealant in it and it's not leaking anymore

Jasonoff

Nice! Easy fix then.

Edit: Was it both bottom bolts, or just one of them?

bullitt69

It was the lower bolt hole closer to the gearbox. It is surprising that even these cars have production flaws

Jasonoff

Were your mounts ever replaced? Are the bolts the same length? Is it possible someone used a bolt too long and damaged your upper pan casing?

BLKROKT

You know, I've heard of that happening on Mustangs before. Therefore all cars must have this defect.

bullitt69

It doesn't seem that my mounts were ever replaced and all the bolts were of equal length.

Jasonoff

Cool, thanks for posting back with the solution.

Alex.currie44

Old farts sometimes can recall old ways.
Put a UV oil based dye in the oil in very small quantity and it will flouresce under UV light. If it does it ain't the mounts and it will help locate exactly where it is leaking from.
http://www.autozone.com/test-scan-an..._0_0?location=

bullitt69

I'm glad to be of any use!

Unfortunately there are still some problems I'm experiencing with the car which I can't resolve based on the information on this forum.

bullitt69

I was actually planning to do exactly what you're talking about with the dye, but my mechanic and I managed to find the source of the leak visually.

gnasher

Hi all

is it possible to change the engine mounts without lifting out complete engine?

Veight

I'm thinking of buying a C63 so spoke to an engineer at Mercedes Benz World who experienced the exact oil leak you have. He said its because the engine mount bolt on some cars goes too far in and actually punctures the block. The only cure is a new engine.

Jasonoff

If anyone is tossing an engine because of this I will take it.

Steven_C63

That is complete horse ****. If any of these engines had longer bolts puncturing the block then it would have leaked as soon it ran for the first time. All the bolts are the same length on all the m156 built you can believe that. I recently had the same leak. Pulled out the same bolt OP did and oiled poured out. Only explanation is oil is leaking from somewhere higher or maybe it’s left over oil from a previous leak that collected in that area.

bullitt69

The reason for the leak is long known now for the m156 - blown gasket between the upper and lower pans.

Solution is to reseal it. Here is the video of the procedure:

bullitt69

I spoke with Tasos over IG a year ago and he sent me videos explaining the problem in detail.

IG of Tasos:
https://www.instagram.com/tasos_moschatos/

Steven_C63

That is not the source of the leak. The engine mount bracket is above the oil pan. It’s the bed plate. Need to remove the engine and it’s basically almost a rebuild at that point in order to re seal.