Hello All! Ive been pondering this question in my head for a while. I currently run 10W-40 in my 3.8L V6. I figure Id use a little thicker oil casue of how old the engine and car is. But, with winter around the corner, im wondering if it will be too thick when the temps are a little bit cold. It never really gets below 5*F around these parts of Pennsylvania. Im just worried if I keep the same thick oil that when trying to start it, the oil won't be thin enough to adequately lubricate the engine at cold tmperatures apon start-up and warm-up. I don't want any more pre-mature wear on the old engine. Should I switch to 10W-30 or 5W-30 during the winter months or am I just fine? Thanks in advance...

-Adam

I would go to a 10w30. It will perform well at that temp, and the closer the 2 viscosities the better the oil.

Hi 87Delta, andrewk, hello everyone,


Starting problems last winter? Any problems now?

I use 10w-40 in everything I own, new or old.

Two 350s are factory. Two 283s, one 439, one 461, and one 468 are all my "builds".
The other 468 was built by a "West Coast" Pro for the previous owner of my Red Coupe.
454 will use it also, when I decide what car to put it in.

If it ain't broke, don't fix it.

Regards, Norm

Norm, I just got the car in May, don't know how it'll act in the winter. It's already hard to start most times anyways, but thats another story. But, your right, if it ain't broke don't fix it. Im just a little worried about the engine wear.

Hi 87Delta, All

Another brain fart. I was confusing your zero with my freezing. I only see 32* a few times a year.

I believe andrewk experiences the same weather as you and I would take his advice about the first number. 5w is used, year round, on new engines that are machined to smaller clearances than ours.

Since the second number (40) works now, it will work fine during the winter.

Bearing in mind, oil thins as temp goes up, 10 is the normal (I would guess, at 70 or so degrees) viscocity of the oil. When at operating temp, it will be the same as 40 would have been at the same temp. Actual viscosity, of 10w-40 at operating temp, might actually be 5 or less.

Regards, Norm

I have never had a problem with 10w oils in the winter, but I always let my vehicles warm up. The reason I suggested a 10W30 as opposed to a 40 is because the smaller the difference in the 2 viscoities, the better the oil will perform. Maybe I have spent too much time on ROP, but I remember a long discussion about oils and their different properties. The general concensus (after much flaming typical to the ROP style) was that the closer the 2 viscosities in a multi-viscosity oil, the more likely they are to actually perform as advertised. Not to say that 10w40 wont work, but that is just my understanding. If you are seeing single digits for extended periods of time, I would go to a 5w30 to be safe. Hope this helps

Andrew

Thanks for the help guys. Usually when I leave the house at around 7AM it's no less then 20* through the winter, but sometimes it can be lower. I tend to let the car warm up and idle for about 7 minutes prior to leaving anywhere so I should be all good. Im not typically interested in super high performance, just something thats constant. So far with the 40 its ran great (knock on wood) just wanted to get some light on the matter of oil. Thanks again.

OK... can anyone explain what the second number in an oil spec is? I am aware that the first number in 10w-30 is 10weight (thickness) of the oil. What is the second number 30 represent?

Hi 88delta88, All,




10w 30
10w = 10w cool
30 = 30w hot

Regards, Norm

Thanks norm... Didnt realise you had just explained it!