Pontiac Grand Prix Forums : Grandprix

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

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Wolfgang "Wolf" Balandran
'02 GP GT coupe
'73 Firebird
Member of the Pontiac Oakland Club

Sounds like a lifter pumping up

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99 GT - 2.5 Catless DP, EGR delete, Custom Tune

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.

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Click my sig for updates and pics of my car!

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,

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Wolfgang "Wolf" Balandran
'02 GP GT coupe
'73 Firebird
Member of the Pontiac Oakland Club

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.

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FQuick S1X Cam | 3.3 MPS | Pacecrappers | VTEC

Lucas Oil Stabilizer.

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

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2003 Blue-Black Metallic GTP Sedan - Almost Done...
2007 Gold Mist Chevrolet Cobalt LT - Custom CAI, NGK V-Power's, Muffler Delete, Custom Tuned PCM...Sure does have every bit of 130 FWHP
http://www.cardomain.com/id/03blueGTP

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,

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Wolfgang "Wolf" Balandran
'02 GP GT coupe
'73 Firebird
Member of the Pontiac Oakland Club

How hard is it to change a lifter? And would I get away with changing one or should I do all?

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^^I realize a stock L36 is not as fast as the sticker implies, but this sticker has worked and it is still a hell of a lot of fun to drive considering it's a grocery sedan.

If your there, change them all. It's not to hard to do if your somewhat mechanical

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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.

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2004 GTP CompG. SPO Package.
3.6MPS, 3" DP, Powerlog, 180Tstat, Wizair, Autolite 104's, 20* timing, PRJ Wires. PRJ Tune.

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.