Rock bottom temp you would run a conventional oil

[Saturn_Fan]

What is the general consensus as to what is the absolute lowest temperature one would run a conventional oil in their vehicle?

I am running Pennzoil 5w-30 conventional right now, but seem to think I have no choice but to go to a syn for the winter months here as the temps can be -20F.

Yeah, I know PP is only 10 bucks more each OCI than regular Pennzoil in the five quart jug.

 

[GMFan]

I don't know. I mean, 10w30 is good even into the negative degree ranges.

It never gets that cold here. Coldest is usually in the single digits. My father and brother use 10w30 conventional in their chevy trucks without issues.

 

[Hermann]

If I resided where it can get to -20F or less several times a season, that would be my limit. But would also be dern sure that the synthetic has a pour point of -40F. Below that you should use block heaters for that first start of the day.

 

[WishIhadatruck]

In college before I knew much of anything about oil we had a J10 Jeep pickup (1977 model?) with a 360 v8. We used QS 10W-30 I believe and it always started right up until it dropped below -20 degrees F. At minus -35 it needed a jump start but still started. We didn't know enough to be worried about the oil.

I know more and can afford to be a little more paranoid so I usually run synthetics now even though it doesn't get quite as cold around here as where I went to college. I think synthetics really start to shine south of 0 deg F.

 

[MGregoir]

5W-30 unaided (no block heater) starts end around -25 C. Not because it's too hard to start, but the oil is too thick.

5W-30 synthetic would be good to -35 C or lower and 0W-30 is good for -40 unaided.

 

[SevenBizzos]

Where I live, it can get to -20F every year or so (and once in awhile colder). I've never really given it a thought.

If I had to pick a number - -60F ?

 

[Drivebelt]

I use 5W-30 conventional year round and it frequently hits ~ -30C (-22F) here in the dead of winter.

-35C (-31F) is about the limit I would want a 5W-30 conventional in my car.

 

[cmhj]

What I did before syn was readily available is far different than from what I'd do today.

-10 F.

 

[blackcherry06]

In January 1986 it dipped into the -40's in Gillette, Wyoming and all 3 family cars had Castrol 10W-30 in the sumps. Even my 1978 Chevy Monza 2.5 Iron Duke, which sat outside, started with only an electric battery blanket to assist it. My mom's '85 Accord SE-i had no problem, and my dad's '82 Celica started with no issues at these temperatures. The oil was probably like molasses but it caused us no problems. 10W-30 was considered a winter oil back then. 78 Blazer, 86 & 91 Civic Si, '72 Monte Carlo, '87 Silverado, '82 Silverado, 85 Olds Calais, and several others all survived years of Wyoming winters with dino 10W-30, be it Penzoil, Castrol, etc.

 

[bob_ninja]

As Drivebelt said, here in Canada we have many days at -10F and -20F sometimes. Of course, many car owners are ignorant and use whatever 5W30 or 10W30 their mechanic puts in. While cars still run fine during winter, they will develop leaks sooner. So cars run but engines don't last as long as further south.

I use synth and more recently mix in some dino 5W20 during winter and my engines never need a topup. On the contrary I always end up overfilling.

My rule is to at least use a blend at 0F and below. Around 20F I would use more synth and less dino. Then again it depends on how long you want to use that engine.

 

[addyguy]

I've used a lot of Pennzoil 5W-30 over the years, and started many different car down to between -25C and -30C, and never had a problem. Even though it has a mid-pack ccs number at -30C, I still think Pennzoil is one of the better dino oils for cold weather...might be the groupp II+ basestock that helps with this.

 

[Audi Junkie]

Zero F would be a definate cut-off for me.

 

[mechtech2]

For a 5-20 or 5-30:
If it got below -10 deg F more than 10 times a year, I would consider a full synthetic engine oil.

 

[Gary Allan]

Quote:
Rock bottom temp you would run a conventional oil


All. That's what they did before 1974.

 

[Saturn_Fan]

Wish there was a longevity study that could correlate synthetic in freezing weather with extended engine life.

 

[Saturn_Fan]

The 0F was always what I thought of too as the lower limits of my comfort level with non-synth.

Alas, I will run continue to run synthetic in the winter time here.

 

[Gary Allan]

Originally Posted By: Saturn_Fan
Wish there was a longevity study that could correlate synthetic in freezing weather with extended engine life.



Hard to do. The most longevity increasing item was probably EFI. A 60k engine was somewhat worn and 100k was something to brag about ..10k a year was exceptional ..etc..etc.

 

[Saturn_Fan]

Thanks for the input Gary.

 

[HighRpm]

my sis saturn stick has close to 190k and 5w-30 all yr round... without any issues. Just let the engine run abit before taking off after start up. For ex, startup and brush snow/ice off then enter car to put seatbelt on. Ur ready to go by then.

i run 10w-30 every oci Mobil 1 that is w/o any problems......

 

[Gary Allan]

Originally Posted By: Saturn_Fan
Thanks for the input Gary.

I don't know if you liked the input or not ..so I'll say a bit more

I really doubt that there are engine longevity studies of any type (with this topic as the "quest-ion"). Now there may be some where they measured the wear at startup in subfreezing weather. This, AFAIK, never EVER suggested engine longevity.

For example, as "thin is in" in the halls of SAE, you see all kinds of studies (some referenced by the good Dr. Haas) that "suggest" that lighter oils perform better and are better in all terms of usage.

One such study showed that diesel engines suffered less wear in extreme cold starts with 10w-30 vs. 15w-40. This was in concert with the "thin is in" agenda. What the study didn't say is that startup wear in most commercial diesels will probably not amount to too much in terms of their longevity before overhaul.