8.1 And 10w40 Oil

[djv1951]

Is any one using 10w40 oil in their 8.1. If so, does it cut down the amount of oil it uses?

[jro909]

thats some heavy oil, i'm sure it make decrease the oil consumption but your going to lose mileage and the thing is going to be a bear to start in the winter

[dewfpo]

When I switched to 5W40 my oil consumption went down, not I have 0W40 in it but haven't driven it enough to know if that changed the oil consumption any.

 

DEWFPO

[DwayneJ]

jro909 is completely wrong.

 

A LOT of people have put 15w-40 in engines "spec'd" for 5w-30 and don't have any issues so long as they don't do it in the dead of winter, don't know anyone who has tried that yet. the thin oil specs are a CAFE thing and the same exact engine shipped overseas often gets a thicker oil spec. I know my car says 5w-30 on the oil cap BUT it was popular in the middleast and was spec'd 15w-40 there. I don't want to hear about heat either because it does get cold in the desert.

[RLB-Motorsports]

The main reason 5W-30 oil was specified for your engine is to increase the CAFE (Corporate Average Fuel Economy) reported to the Federal Government. CAFE is the combined average fuel economy of all of a vehicle manufacturers product line. Minimum CAFE levels are specified by the Federal Government. In order for a vehicle manufacturer to continue selling profitable large trucks and SUV's, which typically have poor fuel mileage ratings, as compared to smaller cars, and still meet mandated CAFE requirements, they must also sell enough of the smaller cars which have much better fuel economy ratings to offset the poor fuel economy ratings of the larger vehicles. For model year 2001, the change to a 5W-30 oil will allow overall CAFE to increase by a very small amount, typically in the tenths of a mile per gallon range. 5W-30 oil is a lighter viscosity than a 10W-30 oil and therefore has less internal engine frictional losses, or less drag on the crankshaft, pistons and valve train, which in turn promotes increased fuel economy. This increased fuel economy is virtually undetectable to the average motorist without the use of specialized engine monitoring and testing equipment under strictly controlled test track driving when comparing a 5W-30, 10W-40 viscosity motor oil.you will not see any diff except in oil use! GM states in several service bulletins that about 1 quart of oil per 2000 miles is norm! just when threw the argument about 5 years ago with a 2002 GMC Yukon Denali with a 6.0 after the customer got a layer gm put a new engine in and wouldn't you now it uses almost as much oil as before.