10W-40 + 5W-20 = X

[HawkeyeScott]

I've got some current generation Pennzoil High Mileage 10W-40 I bought for my old Jeep 4.0 when the oil was on clearance. I've since sold the Jeep and now have a 2000 Durango with the 4.7. It's spec'd for 5w30. So, I'm thinking of buying some of the same oil but in a thinner weight, to thin out of what I've got and then use it in the Durango.

Do you know what a 50-50 mix of the 10W-40 and 5W-20 would actually be? I'm guessing the straight 10W-40 would be fine in the summer, but I might try and use it up sooner since I'm just around the corner from an oil change.

Thanks a lot.

 

[dubie2003]

What about running the specs thru the calculator? It's not 1 to 1 so more exact numbers are needed.

 

[tommygunn]

It'd be a high 10w30, just short of a 40.

Pennzoil High Mileage 5w20 is on the thick side of 20, almost a 30. Most High Mileage oils are thicker than their regular counterparts.

Her's the PDS

 

[HawkeyeScott]

Thanks, Tommy.

Maybe I'll use a different ratio to thin it out some more.

 

[Nickdfresh]

I wouldn't worry about it and use it in summer...

 

[crazyoildude]

i used pennzoil high mileage 10w40 in our old Chevy 1990 tow truck that had over 250,000 miles and it ran good the only drawback was the truck was underpowered and the thick 10w40 slowed it down even more. But it ran good and slowed the oil burning.. How does it look when the local engine shop has a truck that smokes and leaks..We traded a rebuilt engine for that truck it had 185,000 abused miles but always ran when we needed it. we used that truck all the time.

 

[KCJeep]

If you run it 50/50 you'll never notice a difference, I just did it in my son's Chrysler to get rid of some 10w40 I didn't want. But you can also just use 1 quart of it in everything when you change till its gone as long as you don't have warranty concerns.

 

[CATERHAM]

Originally Posted By: tommygunn
It'd be a high 10w30, just short of a 40.

Pennzoil High Mileage 5w20 is on the thick side of 20, almost a 30. Most High Mileage oils are thicker than their regular counterparts.

Yes 50/50 mix will give you a 10w30.
I'd suggest a 60/40 mix with any 5w20 conventional that will give you a lighter 10w30.

The only way to make a 5w30 would be to use a high VI 0W-20 like TGMO and you could then go with a simple 50/50 blend to make a syn blend 5w30 with a pretty impressive 180 viscosity index.