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engine knocks when cold

W

Wolf02GT

New member
Hey Guys,

Got a strange one. I have an '02 GT. L36.With about 67,000 miles. When I first start the car, it has a strange knocking sound.Then after a cpl of minutes,the knock goes away. The car seems to run fine. No oil burning. It does seem to be losing coolant,however.And I can't seem to find the source of that leak. any ideas?

Thanks for any help!
Wolf
 


X2 on the lifter pumping up when it comes to the noise you are hearing.

Loosing coolant on the other hand can be a more serious problem. You should really replace your Lower intake manifold gasket as they are known to be a huge problem on L36 motors. You are probably loosing coolant their. Look around near your fuel injectors to see if you have little puddles of coolant. It's a tell-tale sign this gasket has gone bad.
 
Thanks guys,

I'll check for the coolant leak. Any thoughts on the possible lifter issue?A fix? Could the knock also be a bad PCV valve?

Thanks again,
 
My car did this when my LIM gasket was going bad. Once I replaced the LIM gasket (due to oil and coolant mixing)... it stopped.

Pull off you oil cap, and look at the inside of the gap. Mine looked like baby $hit. Better yet, drain the oil and see what color it is. It should be black if normal used oil. If it looks like chocolate milk... your LIM gasket took a dump.
 
Lucas Oil Stabilizer.

Done. Use it and if the sound goes away...you needz some new lifters probably.
 


Lawngoose said:
My car did this when my LIM gasket was going bad. Once I replaced the LIM gasket (due to oil and coolant mixing)... it stopped.

Pull off you oil cap, and look at the inside of the gap. Mine looked like baby $hit. Better yet, drain the oil and see what color it is. It should be black if normal used oil. If it looks like chocolate milk... your LIM gasket took a dump.
Click to expand...

Well, My oil looks good. I did us some Duralube. No change. Oh,well. Looks like maybe my lifters may have taken a dump! Thanks for the advise!

Have a good one,
 
ive got the same issue. although it did improve a lot when i stopped using amsoil and switched to valvoline.

is there a way to test the lifters without tearing stuff apart? im brining the car in soon because I too have an intake gasket leak (oil analysis verified this). i was wondering if i could have the shop test my lifters while they are looking at my gasket leak too.
 
The 3.8/3.1 GM V6 motors are notorious for "piston Slap" when cold-nothing to be concerned about if that is the noise. They all do it when cold and it goes away once the engine heats up. No effect on durability as long as nothing else is wrong and you don't rev the engine to 6,000 RPM when it is cold.
 


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