What about oil viscosity in the winter?

[Nick1994]

I've got a 1996 Chevy C1500 Silverado with a 5.7L and 156k miles. I got 60-70 quarts of NextGen MaxLife 10w40 in the O'Reilly's promotion in May with the coupons for .33 cents each, I've been running that but why does the viscosity matter so much in the winter? I understand thicker oil is even thicker in the cold on startup, but I live in Phoenix, AZ where our coldest morning of the winter may be 30-35 if you're lucky. I've heard 10w30 is fine until 0 degrees, so if the 10 is the startup viscosity, wouldn't 10w40 be just as easy to start up on? And the 40 being the operating temperature viscosity, wouldn't it all even out, especially since I'm not in a cold climate like Canada? Any input is greatly appreciated.

I have some Mobil Super HM 5w30 from the same sale that I got for .50 each that I was planning to run in the winter regardless, but winters after that I have so much 10w40 on the shelf.

 

[aquariuscsm]

In AZ you could even use 20W50 in the winter :^) Your 10W40 will be perfect.

 

[beast3300]

A 10w40 will be thicker across any temp range over a 10w30. So at the exact same temp like 35 degrees the 10w30 would flow better vs the 10w40. Is it gonna break the old 350 Chevy engine? Definitely not. Would I personally prefer a 5wXX oil? yes.

 

[SLCraig]

In AZ, I would just run your regular oil year round...
Where I live, the temperature fluctuates a lot, and that might be more of a reason to use a 0w or 5w instead of a 10w, as example.

 

[danthaman1980]

In Phoenix, the 10W-40 would be fine all year, but since you have some 5w30 I'd use that up over the next few winters, and just use the 10W-40 in the warmer months. You may find some more 5w30 for super cheap for subsequent winters - if not, 10W-40 will be OK too.

 

[Cristobal]

Do not listen to the people who think ALL of Arizona is warm & nice all year. Like me in California, it depends where you drive to. If during the winter you stay around Phoenix only, 10W-40 is fine.

If you go up to Flagstaff or the Mogollon Rim, either use a lighter grade or do what I do. this depends on the weather when you go there.

I will sometimes add a quart of MMO before a winter trip. This will thin it down. Or I just run a lighter mix in the winter, with some 0w30 in the mix. A lot of times if I have the heavier summer mix in, I will keep the crankcase about 3/4 quart low, in anticipation of such a cold weather trip. A quart of MMO will knock the viscosity down maybe five points.

Grades like 10W-40 are always to be had for a lesser price. That's why I use them a lot in mixes. But in the American West, weather can vary a lot. Ely, Nevada, for instance can see 50 degrees F. one day and three days later see fifteen degrees below zero. I always try to anticipate.

 

[Bryankkkk]

I ran 10w30 in my truck all year round, ran fine on those -10 degree mornings haha

Your 10w-40 will be fine for your Arizona Winters.

 

[Cristobal]

Aquariouscsm, there are some spots in Arizona where he might want lighter oil in winter. Of course in the American West it also depends on the time of day you start your engine. In a place like Ely Nevada it might be -15 degrees at five o'clock in the morning, but by 9 o'clock it might have warmed up to thirty degrees.

 

[bepperb]

One thing to understand is that oil does not change viscosity in a linear fashion. As it gets colder and colder it increases viscosity much more quickly. So while it might not change much from 80 to 60 degrees the difference in viscosity between 30 and 10 degrees is significant.

In your climate 10-40 year round is fine, if it never gets much below freezing.

 

[KrisZ]

Well, if you are the one to follw the recent trend on BITOG, I think nothing but super, ultra high viscosity index 0w20 oil should be used in your case, everything else is just too thick...

 

[3putter]

your 10/40 would be fine, even in a colder (not frigid) climate.

 

[A_Harman]

Originally Posted By: KrisZ
Well, if you are the one to follw the recent trend on BITOG, I think nothing but super, ultra high viscosity index 0w20 oil should be used in your case, everything else is just too thick...

That is, until 00W-16 becomes available.

 

[dparm]

Your car is water cooled, not air cooled...therefore you don't really need to change oil weight in the winter time. Keep doing what you're doing.

 

[TFB1]

Originally Posted By: Cristobal
Aquariouscsm, there are some spots in Arizona where he might want lighter oil in winter. Of course in the American West it also depends on the time of day you start your engine. In a place like Ely Nevada it might be -15 degrees at five o'clock in the morning, but by 9 o'clock it might have warmed up to thirty degrees.


But the oil in the pan probably hasn't warmed past 0* in that amount of time...

 

[Merkava_4]

You gotta alotta guts running 10W-40 during the winter. Alotta guys on this board would
pass out from shear terror at the mere suggestion of running 10W-40 during the winter.

 

[Garak]

Originally Posted By: Merkava_4
You gotta alotta guts running 10W-40 during the winter.

Nah, if he tries it up here, we'll talk.

 

[demarpaint]

Originally Posted By: A_Harman
Originally Posted By: KrisZ
Well, if you are the one to follw the recent trend on BITOG, I think nothing but super, ultra high viscosity index 0w20 oil should be used in your case, everything else is just too thick...

That is, until 00W-16 becomes available.


LOL Yea, then wait to see who back specs their engines to it. I wonder if engines that were running 5W30 that were back spec'd to 5W20 with no change to the engine will be back spec'd to 00W-16. LOL

 

[Shannow]

Originally Posted By: bepperb
One thing to understand is that oil does not change viscosity in a linear fashion. As it gets colder and colder it increases viscosity much more quickly. So while it might not change much from 80 to 60 degrees the difference in viscosity between 30 and 10 degrees is significant.

In your climate 10-40 year round is fine, if it never gets much below freezing.


20W-40s and 50s work even in freezing climates...I've used 20W-50+STP, 25W-60, and 25W-70 in temperatures down to -7 C with no ill effects..

Not advocating it, but 10W-40 will be fine.

 

[Merkava_4]

Most of those Chevy Silverados have piston slap with 5w30 anyway.

 

[Cristobal]

In Ely, Nevada it is already going down to 27 degrees F. as per Weather Underground. And it is only September the 26th.

Tomorrow night will be that cold with a high of 55 degrees.