What weight should I use?

[jason]

Hi Bob,

I have about 17,000 miles on my C5 Hardtop. No problems. Someone told me to change from the 5w to the 10w. Should I stay with the 5 w I have been using, or being the engine has some mileage on it now, go with the 10w super syn?

[Robert Pache]

Either viscosity is satifactory and approved for use by Corvette. I personally prefer Mobil1 10W-30 for use in my Corvette.. The 5W-30 will give slightly better fuel economy and is used to certify the Corvette engines for fuel efficiency standards. This is why it is the primary reccommended grade.


Bob

[jason]

Bob,

What you're saying is that the 10W would protect better than the 5W, but being it's a little heavier would put some drag on the engine, which would lower the efficiency of gas mileage? I would rather have more protection than better mileage, and being that I drive the car in traffic, I would rather have better protection than mileage by using the 10W. Correct me if I'm wrong.

[Robert Pache]

There is no real protectoin for the 5W-30 over 10W-30. Both grades need to pass rigoros engine testing standards. I just personally prefer the 10W-30 grade.

Bob

[jason]

Just curious. Why do you prefer the 10W?

[Robert Pache]

Just an old timer who personally likes the heavier grade.

Bob

[fatherlarry]

I'm with you Bob!:nod:

[Robert Pache]

You can use either the 5W-30 or the 10W-30. At 17,000 miles, the engine is just broken in and should have no oil consumption problems. At operating temperature, say around 220 F both grades are identical in viscosity. The lower vis oil will pump up a little faster to critcal engine parts at startup especially at low temperatures. The 10W-30 willo have slightly higher film strenght at operating temps. The choice is yours.

Bob

[jason]

Thanks Father and Bob. I usually take stock in what old timers have to say.:lol: I think what I'm going to do is in the warmer weather use the 10w, and 5w in the winter, being I don't use the Vette that much. Thanks for your input.:nod: