Jaguar 2003 x-type (x400) auto
My car started to idle really rough and konk out after a while - mechanic says compression is low and should consider a
re-build or second hand engine - only done around 160k - surely this is a wrong diagnosis and has anyone had similar
Problems and what was the solution?
The car has been serviced regularly etc. and I am lost for answers

 

Stirling, to diagnose what is wrong, you are going to need to make a tool. All that it amounts to is a tube with the spark plug threads on the end that you can attach to an air compressor. From there, you rotate the engine so that the affected cylinder has both the intake and exhaust valves shut. You can then apply air (most places recommend filling it to 90 PSI) to the cylinder. With the cylinder pressurized, you simply start listening. Open the oil fill cap, can you hear air there (if yes, then you have a bad valve guide seal). Listen to the end of the exhaust (if you hear air hear, you have a problem with your exhaust valve - something blocking it, bent, etc). Listen to the intake (same sort of problems as with the exhaust valve). Finally look in the overflow bottle for signs of bubbles (if you see bubbles, then you have a bad head gasket).

If you are not getting any signs of air escaping, then you can question the diagnosis.

 

Thanks for the input - I rang up a jag mechanic and he said he would look at it and he has the diagnostics equipment to find the problem - he thinks the other mechanic may not have the correct diagnostics tools to do the job - hopefully the it ain't that bad ��