My car recently overheated due to radiator leak and I got the radiator replaced. Mechanic told me I didn't have any head gasket problem at this point.

When collecting the car I noticed it was not peppy like before and in this sense seemingly sluggish. I knew they added some oil(they insist it was the correct one) though I thought it was kind of black when I saw the dipstick so I thought the oil might have caused the engine to behave like this however I done an oil change and mechanic has told me 0.5liters of old black thick oil etc won't make the car less peppy or sluggish since I have put the new oil in there.

He then told me if the car overheated, they changed the radiator and it is now sluggish, this means the overheating damaged the engine. I asked if there was a way to diagnose this including using compression tests, he said 'no, you can't. The only way to know is to get a dyno done and see how low the bhp is'.

  1. Is his statement correct? If not how can I go about diagnosing such damage?

I am also noticing increased rubber(probably clutch smell) in 1st and 2nd gears however when the car originally felt less peppy\sluggish I don't remember getting these smells. It could be that the whole thing is due to the clutch coincidentally failing during the overheating situation, or it could be the clutch starting going shortly after or in parallel and is not related.

Anyway I'm not sure if this is a clutch issue or the engine has been damaged from overheating. I really don't want to replace the clutch only to find the engines worn out.

  1. If you suggest dyno or compression testing etc to know if the engine has been damaged, will these work regardless of whether i have a working clutch or not?

Any other advise will be appreciated.


  • you could do a Morse test... – Solar Mike Oct 27 '18 at 20:55

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