mixing diff grade oils

Why not just use a good 0W30 synthetic?

 

Ok I gotcha. Chicago has pretty cold winters right. Roughly how low are you expecting your starting temperatures to get down to, 5F? 10F?

At 1500 miles per week I'd say the oil is getting a pretty good workout. Personally I'd prefer a 30 weight oil in there for this type of duty, but I understand you've got the cold start issue. Maybe try 2.5 qts of 5W30 and 1 qrt of 0W20 which would probably just give you a thin 5W30.

 

Good questions. Ans = 2.5W-25? do not know. We could do viscosity blend calcs, but I assume average is close enough for goverment work. I am going with 0W-30 Mobil-1 Advanced Fuel Economy but not sure they still make that grade, its older, as I am as bad as you on long storage. Hopefully shelf life is good.

Your consumption rate sounds high. What brand are you using?

 

One quart in 4000 miles is not really too bad for an engine with 150,000 miles that's doing 1500 per week. I mention the weekly mileage because many cars use significantly more oil at freeway speeds compared with lower speed driving.

Sure the situation's not ideal, but it's not all that bad.

 

Here's another option. If you're not experiencing any cold start issues with the 5W30 then just keep using that as your main fill, and use the 0W20 for top-offs. By the time you need to top-off there's probably a little bit of oxidization thickening started, so the 0W20 should maintain a good viscosity.

I'm doing a similar thing, but in reverse, here at the moment. I've got some 10W40 that I need to use up so I'm using it for top-off in summer. However I only need about 1/2 pint of top-off per 4000 miles, so it's going to take a while to use it up.

 

use 0-20 all year long since the cars where new. I have never added a ltr. between changes. Normally go 14,000 thousand kilometers before oil and filter change. Filter on my HCH is every other change but every change on the Prius. I would not mix all-though I can't really see it hurting anything! Hal

 

Oil does have a shelf life, but it's longer than most people would keep it. It keeps even better in the plastic containers than it did in the old metal cans. I wouldn't use it after 10 years, but I have no facts to back that opinion up with.

I had a bunch of Mobil 1 10W30 I wanted to use up so I mixed it one litre per change with Mobil 1 5W30 in the Prius. The lighter 5W20 and 0W20 will escape a little faster and be burned. I don't notice the oil level dropping over the standard change interval, probably because fuel is replacing the lost oil, or it just isn't burning enough to notice. Currently I'm using 5W30 for all 3 1/2 litres. I suspect it's colder here than in Chicago, on average.

If you do mix it I wouldn't worry too much about the two being incompatible. These days most oils are compatible with each other. Early synthetics weren't.

 

Yes, all the clearances increase as the engine ages, piston rings and valve guides are the main routes that oil gets into the combustion chamber and lost (burnt). Burning a small amount of oil doesn't harm the engine. It might even do a bit of good at self limiting the wear by increasing the upper cylinder lubrication.

That's what I usually put it down to. I used to have an old Audi that liked to drink oil. Around town it was pretty mild but out on the freeway I had to check the oil level just about every time I got petrol.

Ok the freeway was just an assumption due to the amount of miles you travel per week. I was thinking a long commute but now I see your job must involve driving. So I guess you're driving most of the day and your oil stays pretty warm?

 

I don't think Mobil One would change your oil consumption very much. It might be better if you're doing long drain intervals, but I think ST is ok.

I'm starting to think the best plan is just to stick with the 5W30, 1 quart in 4000 miles is ok, and use up the 0W20 for topping off.

 

Some engines use that much oil from the get go! Valve guides some times let oil by as well as the rings. How many miles on your 04 Allen? Hal

 

...well I was just thinking that Mobil-1 has High Mileage formula in 5W-30 and supposedly helps to reduce oil consumption. I'd be a little afraid to blend different brands, but I think this might be part of a blend with 0W-20.

 

Ok that clears it up a bit. In your original post you said:

 

Sometimes a change of brands can do the trick. I would stay with synthetic if that is what you are using. Toyota has their own synthetic now and that is what I use. It is 6.95 a ltr. here in Canada so would probably be less in the US. Check it out Allen. 4000 miles to burn a quart of oil is not terrible! Hal