Hi All,

I pulled the engine from my Crossfire a couple of weeks ago. It was an M113K V8 that I picked up cheaply at the wreckers. It ran very well but after a while I thought it might have a blown head gasket, as it was starting to loose coolant somewhere, produced a lot of vapour out the exhaust (only while warming up), and was filling the oil catch can very quickly. Over time it got harder to start, and finally it developed a hydraulic lock. When I removed the sparkplugs, cylinders 7 & 8 were full of coolant. So I pulled the engine and swapped it for another one (one that I checked out completely first).

I finally got around to stripping the old engine down to see what went wrong. When I removed the heads, the head gaskets looked OK. All the RHS cylinder bores were perfect along with the main bearing, big ends and pistons. However the LHS cylinder bank bores looked weird. Cylinders 6,7 & 8 all have corrosion/erosion and cracking. When you look closely at the top of the effected bores it looks like the inner Alusil liner is starting to separate from the outer bore (I thought that it was all meant to be the same material)?

Cylinder 8

Crack down LHS of cylinder with some small spots of corrosion/erosion.



Cylinder 7

Scoring, cracks and corrosion/erosion. Some of the dark spots go right into the water jacket.




Cylinder 6

More, scoring, cracks and corrosion/erosion




Cylinder 5

Doesn’t look too bad just a score mark along the bottom




All other cylinders are perfect.

The M113K blocks and heads are a different casting to the NA engines and this engine was produced early in production (early 2003). Does anyone think this could be a factory casting problem or was the damage caused by coolant (or something) sitting in the bores for a long time when it was at the wreckers? I tend to think that the engine had probably developed low compression on a few cylinders and that’s why the car was in the wreckers?

Any thoughts?

 

Your reasoning certainly seems logical and conforms to common sense ( a rare commodity these days). I would present the pictures to mechanics who you know are skilled and experienced, as well as some Mercedes service managers and get some others opinions.
Do you see any damage from the water jacket side of the forward cylinders? That would help in analyzing the situation.

 

You need a new engine if a liner is cracked.

 

From CL770 first paragraph; "So I pulled the engine and swapped it for another one (one that I checked out completely first)."

My post is to inquire about WHY that liner pitted and cracked, and though a new engine is needed with the Mercedes design, liners are regularly replaced on diesel engines. Not all cracked liners require a replacement of the engine.