piston slap question

[mrstg65]

Hello,

1999 Grand Prix se 3.1 litre motor with 130K. I bought this car in May 08 and have had no major problems. I like Pontiac and I really like this car.

That said, I have read several posts about the piston slap issue and would like to know if there is a certain weight, type, or brand of oil that is recommended.
The car has a noticeable knock at startup which does not completely go away until the engine gets to 180 degrees. Also, do you think it is better to let it warm up at idle speed rather than drive off while the car is still cold?

My last question is about the intake gasket problem. The previous owner had the gasket replaced by a reputable GM dealer in 2002 (I have the receipt). I have not had to add any coolant and my oil is good. Even with the slap this motor does not burn or leak any oil. Has anyone ever heard of this problem happening more than once ?

As always your thoughts are appreciated!

[tblake]

Yes I have heard it happening more than once, I hate to tell you that.

The Plus side is, the 3100 under your GP's hood is about the easiest to work on with all that room. If you have to do it again.

[grandprixgtx00]

piston slap is completely normal for both the 3100 and 3400 motors. as long as the slap goes away once it warms up your good.

as far as letting the car idle while warming up, or driving it...i guess it all depends on how cold it is outside. i have always went outside during the winter and started the car 5 mins before i leave...most def save gas that way.

[BNaylor]

Originally Posted by mrstg65

That said, I have read several posts about the piston slap issue and would like to know if there is a certain weight, type, or brand of oil that is recommended.

Use good quality 5W-30 dino not synthetic.

You have a bad case, if it is piston slap. In most cases the noise disappears after a few minutes warmup time even with over 100K miles.

[mrstg65]

Thanks for the good advice...The slap is much quieter after just a minute of run time but at 180 degrees it is totally gone. It has not gotten worse in the time I've had the car and I've logged about 10K miles so far. I can live with it if that's all it is. On further review of my receipts I discovered that the intake job was done twice most recently last year but not by the dealer this time. I will watch it closely, but so far it is OK. Hope for the best I guess...