Hi, I have just had a head gasket set replaced on my 1996 C220 (Petrol. The gasket set was replaced by consulting the actual mercedes data book however since the gaskets have been replaced 2 Camshafts have broken within 2/3 days? Does anyone know why it is doing this ??
The car was put back together incorrectly? Timing chains it wrong position? Oil passages blocked?
Only guessing of course.
Marty
At a guess I'd say the cams broke for lack of lubrication to their bearings. There are oil passages through the gasket to allow oil, under pressure, to move from the block into the cylinderhead for distribution to the cam. Installing the wrong gasket could block these oil passages and after some miles the cam would melt its bearings and seize.
Second possibility: Upon reassembly the cam was not synchronized with the crankshaft - not correctly timed - allowing the valves to be hit by the pistons. This happens when the timing chain (between the crankshaft and camshaft) breaks. Big expensive mess - some new valves, valve guides and camshaft. This horror would be almost immediately evident when the engine was first started.
Third possibility (speculative): The timing chain is kept under tension by an oil pressure actuated ratchet mechanism (or similar). To remove the cylinderhead the chain must be slackened - tension removed - by releasing the tensioner. I speculate that it could be that the tensioner was not reassembled correctly and the chain was untensioned - floppy - perhaps even to the point of jumping links on its sprocket and so losing the correct valve tining as described in Second above.
However it occurred, it's an unhappy situation between you and the repair shop that installed the head gasket. The camshaft didn't just happen to break independently of the head gasket's replacement, IMHO.
Martin Joseph and T G Lambach.
Thank you both very much for replying to my query and you have both confirmed what another garage told me ie- Tensioner too tight, Oil passages blocked or simply put back together incorrectly.
Thanks again and I will now go back to the original garage with some knowledge.
I'd be angry but after I calmed down I'd ask the shop's owner to fix it free - no questions asked, or him to pay another shop to fix it - via court action if that's required. A limited time & mileage guaranty should be included.
The shop owner will want to keep this mistake private - and know its cause to avoid a repeat event.
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