A colleague is out looking at 2nd hand scoobs at the weekend and was after a bit of buying advice. I gave him all I could think of, and mentioned that certain models were occaisonally suspect to piston slap if they'd been run on low octane fuels etc. The only problem is, I dont know how to detect it. Any pointers????

Also any other mechanical things he should look out for???

Thx in advance, Disco

 

Piston Slap on UK imprezas has nothing to do with being run on low octane fuel. Piston slap was most common on MY98 (Though I am not saying it is exclusively a MY98 problem) cars and if your friend looks at a MY98 the first thing I would ask is if it has had a new short engine/piston fitted to cure it.

To detect piston slap the car has to be started from cold. Be very suspisious if you get there and the engine is warm. Basically when you start the engine from cold if it sounds like a diesel until it warms up (Due to the piston being too small for the bore until it warms up and expands) then it probably has piston slap. Someone did record the sound of an engine with piston slap but I don't know what the URL is.

 

Cheers I found the sound clip.

 

Disco,

Where is the sound clip, id be interested to hear it.

Tony.

 

Tony.....http://homepage.ntlworld.com/alan.leslie/

 

Sorry for being a bit of a thickie - what is piston slap and how detrimental to an engine is it?

I have a MY98 which always sounds a bit rough when it is first started from cold, but is fine after about 2-3 minutes.

Cheers

Simon

 

My car didnt sound half as bad as that recording, and i had a new short engine fitted under warranty

The nocking noise sounded the same mind, only not as loud.

 

simon, do a search for piston slap in this forum. you will find plenty of info.

If your car is under waranty still, get it checked pronto.

I had a new short motor fitted on my MY98 sport. They usually just swap the piston on the n/a engines but i got a bit arsy and insisted on a full short motor.

 

Cheers John

Simon