M1 0W-40 in a 5.3L....

[NewGuy]

I put M1 0W-40 in my 5.3L Tahoe (73k total miles) last weekend just for the heck of it. I then put over 1000 miles on it last week. I will admit that the thicker oil (vs. 5W-30) does make the engine a bit sluggish until it gets warm. The engine is quieter and seems a bit smoother under hard acceleration, especially in the mountains.

Why did I change to a thicker oil? I actually wanted to try GC, but the AZ in town was sold out. I have always been intrigued by the comments on the M1 0W-40 website that claims this grade to be their "Most Advanced Engine Oil". I am going to run it for 5-8K and get an OCI. Gas mileage is down about 0.5 MPG on long interstate trips. I would like to see if this oil really does shear down to a thick 30 wt.

I am curious to see if anyone has tried 0W-40 in a GM V-8 engine before. Comments? Projections?

 

[tmus2122]

I too would like to know, I did run 10W40 QS SUV one time when new (2000 Silverado 6.0L)could feel the diff. I now have 90K on the truck, no oil usage. Have been using Chevron/Havoline 10W30, short run on M1 that this board suckered me into, talk about noise. Would like to try Rotella 5W40.

 

[KJA426]

I'm running Mobil 1 0w-40 in my 4.7 Dodge and the only thing I've noticed is that the oil pressure is higher until the engine gets up to about 190 or 200 then the pressure is about the same as Mobil 1 5w-30.

 

[Racerjk]

Ow40 is an outsanding oil for an LT1. I loved it in my Formula, and I would definitely give it a shot in your 5.3.