GM 3800's Tolerate 5w-30?

[aquariuscsm]

Originally Posted By: bigt61
I've used 10W-30, 10W-40, 20W-50, M1 15W-50 and currently 5W-30 Maxlife blend in my old 3800 '94 Pontiac. It doesn't care, runs on anything.


I agree. With these engines,as long as there's oil in it (no matter what brand or viscosity) they'll last forever.

 

[Merkava_4]

Originally Posted By: aquariuscsm
My gf's 98 Olds 3800 ran the best on 10W40. Startups on anything thinner always sounded "clacky" from the top end.


I was hearing something "clacky" the other day with the hood up. Kind of alarming because the engine has always been whisper quiet. Maybe the oil is worn out. I wonder what kind of mpg hit I'd take for running 10W-40.

 

[53' Stude]

Try 20w50, as you seem to love real thick viscosity oils for some odd reason

 

[53' Stude]

Seriously though I would try QS Defy or Pennzoil high mileage in 5w30 first, not a 10w40

 

[Trav]

I thought you might find this interesting.
I have 2 2000 Pontiac Grand Prix's one a GT 3800 non SC and the other a GTP SC. The GT was made in 12/99 and specs 10w30 the GTP was made in 5/2000 and specs 5w30.
Both bottom ends and blocks are identical.

I bought another GTP made in 3/2000 (sitting in my daughters house in Houston waiting shipment) and it specs 10w30.
The only plus point in 10w30 i can see is the almost unbelievable low Noack of 4.7% (Pennzoil Platinum) vs 10.1% for the 5w30.
I think the low Noack may be beneficial in keeping deposits like varnish to a minimum.

If i used the car year round then 5w30 would be my choice in the northern areas of the country.

http://www.pennzoil.com/wp-content/uploa...GF-5-en-TDS.pdf

http://www.pennzoil.com/wp-content/uploa...GF-5-en-TDS.pdf

 

[Nickdfresh]

Originally Posted By: dwendt44
The 3.8 engines I've had never used oil (front drivers, anyway).
I've used 5W-30 in the winter, 10W-30 in the summer.
Newer 3.8s spec 5W-30 year round.
...


So did the older ones actually, my 1990 Buick LaSabre spec'd 5W-30 at most temps...

 

[aquariuscsm]

Originally Posted By: Merkava_4
Originally Posted By: aquariuscsm
My gf's 98 Olds 3800 ran the best on 10W40. Startups on anything thinner always sounded "clacky" from the top end.


I was hearing something "clacky" the other day with the hood up. Kind of alarming because the engine has always been whisper quiet. Maybe the oil is worn out. I wonder what kind of mpg hit I'd take for running 10W-40.


I tried everything from 10W30 to 20W50 (10W40 was the sweet spot) and could never tell any mileage difference. PYB 10W40 was true smoothest oil in her car.

 

[Merkava_4]

Originally Posted By: aquariuscsm
I tried everything from 10W30 to 20W50 (10W40 was the sweet spot) and could never tell any mileage difference. PYB 10W40 was true smoothest oil in her car.


Did that Olds 3800 have roller lifters?

Some people say the 10W-40 is too thick to get to those spinning needle bearings in time.

 

[aquariuscsm]

Originally Posted By: Merkava_4
Originally Posted By: aquariuscsm
I tried everything from 10W30 to 20W50 (10W40 was the sweet spot) and could never tell any mileage difference. PYB 10W40 was true smoothest oil in her car.


Did that Olds 3800 have roller lifters?

Some people say the 10W-40 is too thick to get to those spinning needle bearings in time.


I'm guessing so. It was a 1998 model (3800 Series II).

 

[Merkava_4]

Originally Posted By: aquariuscsm
I'm guessing so. It was a 1998 model (3800 Series II).


Yup. . . . .that be full roller lifters with roller fulcrum rocker arms. I was peaking into a bottle of 10W-30 in my 90F degree garage today. Man that stuff looked thin!