3.1 buick piston slapper oil recommendation

[stainman2000]

Hello all,
Been using 10-30 M1 HM in the Buick with the typical cold start slapping problem. Idid replace the lower intake gasket and got the dexcool pudding out. I saw the TSB regarding a bad number of pistons in these cars(2000-2002?) I forgot whether it was born with 4 bad pistons(size?) out of 6 or, 4 good ones out of 6.
Anyway.My oil is black quite soon after the change(blowby?) and the knock is getting louder as it usually does in the winter, I am going to try a change to Maxlife semisynth and a decent(wix)filter.
for now its still chugging at 75k...

Anyone have a similar expirience or recommendation for these fragile engines?

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[Gunatics_Adler]

Well GM has a lot of piston slap issues in the 3100 and 3400 motors. Not much you can do to make it better outside of getting new pistons that fit properly.

I actually ran 10w30 Rotella in my wife's that had it prior to rebuilding it. Worked well.

 

[PT1]

Try Pennzoil YB dino 10w30. Mobil1 always turned very dark in 1500 miles in all of my vehicles. Not much you can do for the piston slap. I had 2 GM V8 slappers. Very discouraging.

 

[2003f7]

 

[ThirdeYe]

I've tried many different oils in the 3.1 I maintain and nothing has changed the piston slap. It's at almost 100,000 miles and the engine still works great, and it sounds great once it's warmed up.

 

[Gunatics_Adler]

I had to replace 3 pistons in the wife's 3100. Bought some Federal Mogul pistons and she stopped slapping. You could easily see which pistons were the culprits when removing it. The old motor still went 120k slapping. The head gaskets went and it threw a main bearing to kill it. Nothing piston related.

 

[stainman2000]

Thanks for the hearty welcome to the forum everyone.I guess its bad pistons 1-4 update is teflon coated in the 3.1

 

[98dakarM3]

I would give Rotella a shot to see if it quiets things down a bit.

 

[bobfather99]

Sad to say no oil will fix poor design/manufacturing defects.
If an HDEO wont quiet it down nothing will. Give Rotella T Synthetic a try, maybe???

 

[mechtech2]

Thicker oil can help with piston slap noise at start up.
But there is a penalty in cold starting properties, power, and gas mileage.

 

[lexus114]

Originally Posted By: mechtech2
Thicker oil can help with piston slap noise at start up.
But there is a penalty in cold starting properties, power, and gas mileage.


Very true!