If nothing else, a multiweight oil should pump & flow much better when first starting the car, & automotive engineers seem to have reached a consensus that a large percentage of engine wear takes place at start-up. If it was my car/truck, was old w/many miles, & sae 30 seemed to be working fine, I'd probably stick with it. If I did switch, I'd go to a 20w50.
For something newer/fewer miles, w/your temps, I'd probably go to, oh, maybe a good 15w40 multiweight. In a new or almost new car, probably 10w30 except for the hottest part of the year.
Jake,I don't know what engine you have but where you live is a great place for a 30 or 40 wt oil.
With these new base oils,some look really good. The Pennzoil Long Life has a flash point of 498 if I remember correctly with the 30wt and the HD 30 is 450F Flash point with a pour point of -22F so I think you would be safe. At least I have not heard about it getting that cold where you live
I use the 30 wt year round in my Vette with some add to keep the cam alive. In years past I would use straight 40t on a trip during summer heat. Valvoline Racing oil that is,but I don't use it anylonger.
From my view,if the catalyst system is not a issue and the vehicle gets a chance to be run hard on occasion,the newer Deisel Oils are very appealing.They are mostly 15/40's
I have a friend that bought a 1989 Ford 1/2 ton Truck new and is a heat and air serviceman. It has had straight Pennzoil 30wt in it all it's life and last I spoke with him still know motor problems other than a timing chain and he had over 270k on it about a year ago. yep,he like a thick oil,his lake Racer with a BB Chevy gets straight Valvoline 50 wt and a can of STP. I built that motor for him ten years ago,it is still going good and Jet Boat motors usually last 4 seasons at most,,the oil he uses in the boat was not advised by me by the way
[ August 17, 2002, 05:48 PM: Message edited by: dragboat ]
Your engine is designed to run with 30 wt. oil at 180° or thereabout. You know how thin that oil seems to be when you get it hot and pull the drain plug. It seems thin, but that's just right for the engine.
When you start, whether the outside air (and the cold oil) is 40° or higher, the oil is much thicker. Put a bottle of straight 30 wt. in your refrigerator, chill it to 40°, and pour some out. It's thick. When it's this thick it isn't lubricating your engine as well as when it's completely warm.
You didn't tell us what engine you have, so I'll assume that the owner's manual calls for an oil that's 30 wt. when hot. If it calls for something different, fill in the correct numbers.
A multigrade oil, 10W-30 or 15W-40, will flow much better when cool and lubricate your engine better. 15W-40 is usually sold for diesels, but if it's marked "API Service Category SJ (or SL)," it's also suitable for gasoline engines. Either of these will be better for your engine before it's warmed than that 30 WT. Also, don't warm your engine by idling; it really sludges things up. Use 10W-30 oil and begin driving gently as soon as the engine starts. Your engine will thank you.
By the way, don't use cheap oil filters. The filter you buy for $2 or $3 is junk, just as one would expect. Even the higher priced version of the $3 filter in the orange box is generally regarded as junk.
[ August 17, 2002, 11:05 PM: Message edited by: Ken ]
question?-i've used 30wt.oil for 40yr. warm to hot temp. never any problems"
See those last three words? He has answered his own question. It stays warm where he is at.Winters are short there! It is the pumpability of the oil that matters anyway. Take 5 quarts of 5/30 out of the 20 degree F garage and pour those into the engine when changing during winter,,pours slooowww!I my self will take the straight wt with no VI improvers where he lives,,heck,I do it here with the Hotrod without problems
That Ford truck owner might not have done the best thing because in Oklahoma it does get down to 3 F something that will never happen where the poster lives,,if it does I hope I am long gone because that will be the beginning of the end of the world
You are telling him to use a 10/30 in 115F ambient when I am worried about my 10/30 at 91F with the a/c on?
Pretty much the entire Industry takes note a 10/30 dino is good to 90F then a higher grade 10/40 or more multi wt is advised. A true synthetic might be a different story. But synthetic is obviously not the topic oil
We all have our opinions. Next?
[ August 17, 2002, 11:15 PM: Message edited by: dragboat ]