Engine knock when cold?
#2
Le Mans Master
Member Since: Aug 2005
Location: CA.
Posts: 5,255
Likes: 0
Received 281 Likes
on
258 Posts
St. Jude Donor '13-'14-'15
This is commom in SOME LS engines-- if it sounds like an engine rattle and not a pinging noise---
It's known as a "piston slap"--GM has acknowledged this issue and says there is no fix and it won't affect the engine performance or life--
BUT I always let the eng warm up til it disappears before proceding just to be safe
It's known as a "piston slap"--GM has acknowledged this issue and says there is no fix and it won't affect the engine performance or life--
BUT I always let the eng warm up til it disappears before proceding just to be safe
#3
Instructor
I had piston slap when cold on a few ls1 f bodys a 98 TA with 80k and a 00 Z28 with 70k, my 00 vette does not have it 70k (yet...)
+1 on letting them warm up.
My dad still has the 2000 camaro and it has over 100k now and runs great.
+1 on letting them warm up.
My dad still has the 2000 camaro and it has over 100k now and runs great.
#5
Safety Car
#6
My 2001 does the same thing when it's below 40 here, goes away in a couple of blocks as it warms up. She has 80K miles now and still running great.
DocOhm
DocOhm
#8
Race Director
Most common problem is piston slap as was said. If the car is modded you may have a lean condition as the air gets denser when the temp drops. You could also have carbon buildup on the pistons causing detonation but that is most noticable when hot. Probably still worth doing a Seafoam treatment on it - can't hurt.
#9
Le Mans Master
Im gonn say its not piston slap. its cold as hell out and the oil is thick. takes some time to work it through. Thats just valvetrain noise without oil in it. Mine does the same in this cold. Its fine
#10
Instructor
Member Since: Nov 2010
Location: Northridge CA
Posts: 168
Likes: 0
Received 0 Likes
on
0 Posts
What is "Seafoam" treatment
Most common problem is piston slap as was said. If the car is modded you may have a lean condition as the air gets denser when the temp drops. You could also have carbon buildup on the pistons causing detonation but that is most noticable when hot. Probably still worth doing a Seafoam treatment on it - can't hurt.