what weight oil do you prefer? Why?

[mudgition]

We had a post about oil filters a week ago or so and I had to change the oil this weekend so I ditched the fram and went with a wix.

My question is: What weight do you run and why? I have ran 20-50 Quaker state ever since it made a noisy lifter "go away". That was 10 years ago and on a 4.0 jeep. Now it's a SB chev with about 15k on it and I've had no problems.

What do you think? /forums/images/graemlins/thinking.gif

 

[Z3PR]

I've always liked Valvoline. In the summer I run 20/50, and in the winter I run 10/40. If it wasn't so hard to start in the cold, I'd run 20/50 year round.

 

[zcarczar]

I run 5w-30 Penzoil cause I get it for free from work.

 

[BlazerGuy]

Whatever's on sale! /forums/images/graemlins/rotfl.gif

 

[Grim-Reaper]

10w30 Mobil 1 synthetic year round in the burb.

10w40 is garbage...ALL of it no mater who makes it unless it's synthetic. 10W40 is 10W30 with a filler. THe filler is basicly wax. It screws up rings. If you read your owners manual on a mid 80's or newer GM truck GM point blank says they will void the engine warranty if they find you have been running 10w40.

20w50 uses a different base oi thickness so it doesn't have the same problems.

Jimmy I run 10w30 dino oil. It has a oil consumption problem so I'm not going to use $4.25 a quart oil in it. I'm trying Castrol High mileer oil to see if it helps.

Wife's honda has miles on it as well, trying the same oil as the Jimmy.

 

[dyeager535]

I'm going to be running 10W30 on the new motor, have been using 20W50 on the high mileage 350 in there now.

No reason to run 20W50 unless you need to, it just "steals" power, and is unnecessary.

 

[89GMCSuburban]

Some manuals say to run the thickest oil possible for your temperature range. By staying thicker, it holds higher oil pressure. Saying that, I run straight 30wt in the summer with 10w-30 in the winter. Thicker oil does rob horsepower, but not enough to worry about. It can also slightly decrease fuel mileage. This is whay a lot of manufacturers are using thinner oil. Ford now uses something like 0w-30. GM, I think, still uses 5w-30. Using the lighter oil slightly improves mileage, but with CAFE averages, they need to eek every mile out of every drop of gas.