My sti 3 has just developed a loud knock at low revs its coming from the top of the engine at the right hand side and only happens when it's warmed up! Any ideas what it could be?

Thanks dan.

 

sounds like engine out time......

 

Do a compression test!! Could be a valve!

 

Sounds like the chocolate melted m8

 

But if the chocolates melted how come it runs fine when it's cold?

 

could be one of the hydraulic lifters

 

An STI V3 has solid followers and if it was a problem with them it would be hot or cold, they also have a type of forged piston which are pretty good compared to cast, so I doubt it would be that. My bet would be crank/big end, for what it takes to do I would warm it up and drain the oil through a clean sieve and check for bearing debris. It may sound like top end but it can be that the bearing/big end is that worn the piston is hitting the head, this will also be worse when warm as the oil is thinner.

 

Hold it on 2500 RPM if it knocks like a bitch it's time for a full rebuild. As above look for shell debris in engine oil.

 

Usual indicator of big end knock is to blip the throttle between 2000 to 4000 revs with a warm engine. If you get a harsh growly knock, it's a good time to check the finances.

 

+1 stuck valve hitting piston if you're lucky.

 

Cheers guys I'll check the oil for debris and get a compression test. And hope for the best.

 

Check your cam pulley bolts - we've seen 2 cars this last year where they came loose (!!!) and they give a knocking noise. Also check your timing belt tensioner- they can also knock when they start to fail.

Compression test is a must to rule out head/valve issues, but it could well be the bottom end- particularly as it gets worse as it warms up/oil thins out. Like WMS said, check the oil for signs of bearing debris.