i wonder if anyone out there can help me ,i have a 97 year 2lt sport auto s/w i've had it about 6 months.The problem is i get a tapping noise from the engine when cold (sounds like the cam/dreaded piston slap) done nearly 70k sound goes when hot.If there is anyone that can give me an idea what it can be i'd be gratefull . Thanks

 

silly Q but have you checked the oil recently? My 03 does this occasionally but its generally when the oils low as on initial startup certain things dont get the oil immediately.....when its all warm then its fine though. Just a thought.

 

Is it a tapping or ticking sound. IIRC from reading various guides, Piston slap is more of a knocking noise. If its just ticking, could it just eb the boost solenoid?

NS04

 

it is more of a knocking noise at about 1.5 to 2k rev range but only when cold i need a definative awnser as i need to drive it round france again this summer and i don't want it to pop!!!! I don't want to take it to a subaru main dealer for repair or diagnosis as it will cost me an arm and a leg cheers chaps....

 

if hightower has a 2 litre sport, it cant be the boost solenoid.....

 

LOL How true! Whoops! Read turbo when I should have seen the sport!

If it is a knocking sound it most likely is piston slap, usually its more pronounced when cold IIRC too.

 

injectors tick.

 

Is there a fix for piston slap ??? Is it going to fail at some point??? Some garages i have spoken to say it,s nothing to worry about !!!

 

There is, but it's rebuild! IIRC from other posts most people had theirs done under warranty by the dealers as it tended to manifest itself before 20k miles i.e. generally within a timeframe covered by the warranty.

If it tends to go away when the car is warm, I don't think it's a severe case. I know of a number of people who complain of the same symptoms with their car and live with it perfectly happily. I couldn't comment on whether it results in accelerating the time when your engine goes, I'm not an expert by any means.

Speak to an expert like David at API engines mate.

All the best. NS04

 

Initially it was a short engine replacement, but after so many failures Subaru developed an oversized piston to replace the knocking one. IIRC it was always the same piston, I think it may of been No.2 but not sure.

The check is to pull the injector from the suspect piston to see if the noise dissappears.
As the spark has no fuel to ignite, the lack of pressure of the none exploding fuel does not cause the piston to rattle in the bore.