10w30 Oil in Saturn SL2

Basically in a nutshell, what most are saying is:

Winter 5w30 Summer 10w30

I have a 99 SL2

I just used some 30W to oil the breather filter on my 8N. The temperature was in the mid 20's and that stuff was awful thick.

Ken

Wintertime cold? What's that? Should those of us live in paradise (San Diego) where it gets below freezing less than a handful of times a year (during the wee hours of the night for a few hours at most each time it does so) be concerned about what happens to oil at low temperatures? I wonder.

Well you can THINK what you want. I've a fleet of 35 trucks have run nothing but 30W in them since I took over 7 years ago. The lowest mileage truck has 110k and the highest 295k. None of the engines have even had a valve cover off. Now the transmissions, well that's another story.....

There's nothing "tighter" about modern engines. They are in fact 'looser' to create less friction to keep the mileage specs as high as possible.

What temperature range are they operating in?

story.....

straight

operating

anything

Interesting that what you are saying goes directly against what a factory engineer and several GM trained mechanics have told me. Also, that race engines are built loose to maximize horsepower while sacrificing longevity.

possible.

Even

using.

senior

Corvette

really

straight

operating

anything

It would be interesting to know exactly what you are basing this claim on. At the normal oil operating temperature (around 100 degrees C), straight 30 weight and 10W30 and 5W30 all have very similar viscosities. Depending on the brand, they all have the same additive package. For an engine in good condition (no excessive blow-by) all three viscosities will usually tend to thicken with age and increasing usage. The only significant difference will the the low temperature viscosity. The 5W30 and the 10W30 will both be thicker at 0 degrees c than any of them are at the normal operating temperature but neither will be as thick as straight 30 weight at 0 degrees C. The straight 30 weight will be much more viscous than either when cold. It seems to me that I want an oil that flows well when cold and maintains its viscosity when hot. The 5W30 does this. If you are in a perpetually warm climate, then it probably doesn't matter which of the three oils you use. However, in a cold climate, I'd give the nod to the 5W30 other either of the other two. Comparitive specs for the three grades are readily available from most lubricant supplirer. One example is available from

Ed White

yuppie SUV

straight 30

Depending on the

difference will

maintains its

either of the

available from

I also noticed that he used the term 30W (which I fell into, but then I'm an amateur), which isn't correct because it means that the oil meets the SAE standard for winter usage, which 30 weight oil doesn't. I would expect that a pro fleet manager would have known this.

Ken

They are generally tighter.. if there's oil between moving parts (as there should be), there shouldn't be any real friction difference.

One thing that could be described as "looser" is the use of lower-tension piston rings, which reduce the friction between the piston and cylinder walls. Same with newer piston designs with shorter skirts to reduce the potential contact area.

Well this week it's been 0 to 32. Last summer was 105 at times.

You are correct in what you say. I loosely use the term "W" to mean "weight". Thus 30W = thirty weight oil. Sorry, and thanks for the english lesson. You know when you've been doing this s*it as long as I have, you come to realize it really doesn't matter what you pour in there as long as you change it every 3000 miles.

whatever you say. I thought cold was cold wherever you are.

Thank you for the civility. Might I ask what kind of trucks and engines you have been talking about?

Ken

have, you

doesn't.

I know that I've had cars, trucks, and tractors that wouldn't have started in some of the coldest weather here (MI) with straight 30 in the crankcase. The 2 diesel Rabbits come quickly to mind. They had problems even using Mobil 1 5W-30.

Ken

especially not

hurry.

Had to write the truck numbers down and think about it for a bit.

Think that's it.

I don't see any Saturns listed in there... What are you doing here? Aspiring to own smaller plastic vehicles?

Let me answer here. These are the fleet vehicles. He has an SL1 as a personal vehicle.

I disagree with his choice of 30 as a year-round lube, but as long as he is civil and doesn't descend to personal insults, I defend his right to post his opinions.

Best Wishes,

Ken