Ok, I am going to give a look thru the archives as well - BUT while I am here - I know everyone has an opinion - I am just wondering is it really ok to run 20w-50 in my 3.0 during the summer months here in Tennessee?

A good mechanic friend of mine, who has greatly helped me revive a VERY sick 3.0, suggests 20w-50 in the summer and 10w-40 in the winter. His comment was just use a really good oil, avoid bulk oil at the quick lubes, something like Penzoil(his shop fave), and run it about 5000 miles between changes. His comment was that the Toyota filters are good enough, and the 3K mile thing is really only a concern when using crappy bulk oil. He had no opinion either way with synthetic or dino - as older cars can use either, and newer cars generally just require synthetic now because they ship with it.

I do trust him - ok - I am questioning this - <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> but 20w50 at 5000 miles is a FAR cry from the 10w-30 at 3750 the manufacturer suggests.

Thanks for the opinions and comments. - - Off to the archives....

Aaron <img src="/forums/images/graemlins/confused.gif" alt="" />

I tend to agree with him. Higher viscosity oils seem to work better on well worn engines. I've used 20W40 or 50 in the summer (sometimes even straight 40) and go back to thinner in the winter.

What about w/ the 22r/re ?? Anybody running anything other than 10w-30?
<img src="/forums/images/graemlins/shiner.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

I find I need to run xxW40 minumum to keep my idle oil pressure up in my '85 (~50K on rebuilt engine). I've run 10W40, 20W50 and now 15W40. If I drop to a xxW30 oil, my hot idle oil pressure drops to the bottom of the factory gauge.

I like to keep the low RPM oil pressure up, since a lot of the time I spend wheeling is at or just off idle and can be in the heat as well, even in the winter.

>>>*To understand which oil to use, think of it this way.

A 10W-30W designation means this. When the oil is cold, it flows at the same rate as a straight 10W oil.

When the oil is hot, it flows at the same rate as a straight grade 30W.

Between oils, this does vary a touch, not much. I run 10W-30W year here in Oregon, until the rig gets lots of miles, then I run a straight 30W. In extreme low temperatures, I would consider a 5W-30W.

In racing engines, we would run 20W-50W because of added oil clearences and the oil temp gauge often being pegged at 300? plus...Synthetic, of course....*EB

I run 20w50 all year in my '84 Runner, but it rarely even freezes here. The guy I bought it from had a diesel cruiser and ran 15w40 rotel in both of them. The rotel says it's approved for gassers but i don't know anything about diesel oil.

I'm running the Shell Rotella "universal" oil now, 15W40. Almost all the "diesel" oils will have both a C and S rating (C=compression ignition, i.e. diesel, S=spark ignition, i.e. gasoline) and will work fine in either engine. I have a diesel rig as well and this way I only have to buy one kind of oil. Most of the diesel oils come in gallon jugs and I find the 15W40 weight works well year-round for my climate.

i kind of wonder if i should go 5w30 or 10w30 in my new engine for cool weather driving. i've heard that generally speaking, oils with the narrowest viscosity rating have the most oil and the least polymer additives(for example 30w would be better in this sense than 10w30), but you sacrifice cold starting protection.

i've thought of running rotella 5w40 once my engine is broke in, but now considering 10w40 in the summer and 5w30 or 10w30 in the winter. anybody want to shed some light on this?

Actually, the 10w does not mean the oil flows like a 10 weight when cold. Compare the cold flow rates of 10w-30 and 10w-40, the 10w-30 will flow freer then the 10w-40 at the same cold temperature. the 10w is not the same between the two.

That said, I've run 20w-50 off and on for years, coming from the old engine world of sloppy tolerances. If the engine will hold adequate pressure with a thinner oil, you're better off with it. Thinner oils flow better, getting to places that need it faster, especially when cold. It takes less power to pump a thinner oil, and it's less likely to be sheared. It's been a hard habit to break though.

I tend to run a 10w-40 or 15w-40 oil in the summer on many engines now (as opposed to 20w-50), with a 10w-30 or 10w-40 for winter. Can't say that I detect any appreciable change in gas mileage or oil loss/consumption in the summer times when compared to thicker oils. But in the winter, the engines are much easier to start, and clatter less for the first minute or so.

Bulk oil is a misnomer, and be carefull of that. Castrol GTX 10w-40 is identical, be it in a quart can, 55 gallon drum, or multi-thousand gallon train car. It's bulk storage doesn't change the oil itself. Now that "no name" special that comes in the drum for $20 is a different story. It may be a good oil, but you don't know, so you're gambling if you use it.

I have been running Shell Rotella T SB 100% Synthetic 0W-40 for a while now as well. Same as Roger I run it in my Ford diesel and in both 4Runners because I buy it by the 205L drum.

To alleviate my worries about warm oil pressure and my doubt's about the accuracy of the dash gauge I hooked up a Fluke 744 and pressure module set up to log 20 readings a minute for 6 hours. On a 91 22RE with 280,00km on it the lowest pressure seen after a 5 hour drive in 30+ Celsius weather with 20 minutes of idling outside the store at the end to keep the AC on was just over 10psi.