Dreaded piston slap
Discussion
Well, the past month has been horrendous for my impreza, now to add more pain i think ive developed piston slap.
I put a mild ticking down to my frayed aux belt but just changed it and its still ticking. Checked oil and it was very low. The car had an oil change about 4 months ago so i'm a bit worried.
The web seems to have loads of varying advice about slap but what can i do? Am i on course for bottom end failure? Can i live with it for now?
I'm not shelling out £1.5k for a rebuild so if it goes bang i'll bin the car. Dont want it to come to that though!
Thank god for the subaru section on PH!
I put a mild ticking down to my frayed aux belt but just changed it and its still ticking. Checked oil and it was very low. The car had an oil change about 4 months ago so i'm a bit worried.
The web seems to have loads of varying advice about slap but what can i do? Am i on course for bottom end failure? Can i live with it for now?
I'm not shelling out £1.5k for a rebuild so if it goes bang i'll bin the car. Dont want it to come to that though!
Thank god for the subaru section on PH!
Can't tell without being there and listening to the engine. 2004 WRX with piston slap is pretty rare, not impossible but pretty rare.
Bugeye with piston slap yes, i had that on my old WRX engine and i know of a few that suffered as well, but it lasted ages and a lot of cars can have that for many years without ill effect. Just don't use engine flush when doing an oil change. Carbon build up in the cylinders can help cushion the blow and keep it all quiet as poss.
If the sound is there when the engine is cold and then goes away after a couple of mins then that may well be piston slap. If it's a ticking sound all the time then it could be a valve or injectors being very noisy.
Like is say, very hard to diagnose long distance.
Bugeye with piston slap yes, i had that on my old WRX engine and i know of a few that suffered as well, but it lasted ages and a lot of cars can have that for many years without ill effect. Just don't use engine flush when doing an oil change. Carbon build up in the cylinders can help cushion the blow and keep it all quiet as poss.
If the sound is there when the engine is cold and then goes away after a couple of mins then that may well be piston slap. If it's a ticking sound all the time then it could be a valve or injectors being very noisy.
Like is say, very hard to diagnose long distance.
Subaru's don't use much oil at all so don't expect there to be a significant rise in oil consumption due to piston slap.
Rebuilt engines with forged pistons have piston slap but that's purposely induced because forged pistons are set up to run a bit more bore clearance than normal pistons. This allows the piston to expand a bit more with extra heat produced from extended hard use, higher cylinder pressures etc...
If you do have piston slap i wouldn't bother doing anything about it until something terminal happens. It could run like that for years, as forged engines do, without ill effect.
However, if you have a valve problem or something like that then you may have no option but to make a repair although it doesn't necessarily mean a rebuild. It might just need some head work.
I wouldn't stress about it until you know exactly what's going on but in this case i would be going to a Subaru specialist because they know what to look for and what noises are due to what.
Rebuilt engines with forged pistons have piston slap but that's purposely induced because forged pistons are set up to run a bit more bore clearance than normal pistons. This allows the piston to expand a bit more with extra heat produced from extended hard use, higher cylinder pressures etc...
If you do have piston slap i wouldn't bother doing anything about it until something terminal happens. It could run like that for years, as forged engines do, without ill effect.
However, if you have a valve problem or something like that then you may have no option but to make a repair although it doesn't necessarily mean a rebuild. It might just need some head work.
I wouldn't stress about it until you know exactly what's going on but in this case i would be going to a Subaru specialist because they know what to look for and what noises are due to what.
Its strange,
started about a month ago,
does not always happen,
Goes when the engine is warm
Its more of a gentle ticking than anything else.
From what i have read, it does sound like piston slap. I'll have to see if i can get down to eurospec this week to get a diagnosis.
I'm pretty sure its not going to be good - i just have that feeling.
started about a month ago,
does not always happen,
Goes when the engine is warm
Its more of a gentle ticking than anything else.
From what i have read, it does sound like piston slap. I'll have to see if i can get down to eurospec this week to get a diagnosis.
I'm pretty sure its not going to be good - i just have that feeling.
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