How cold would be considered safe for a 10w-30 in an ohc engine? My cam in block jeep says down to 0f but it's antiquated. Got gallons of synthetic I'd like to use up in the fjcruiser.
How cold for 10w-30?
- Thread starter Chris142
- Start date
Unless you're going waaaaay up into the snowy mountains, I doubt you in CA will ever see temps approaching too cold for 10w30.
Oil has gotten better since your engine was made, so I’d assume it’s even safer at 0F now. I ran 10w30 in the winter in Michigan years ago and didn’t notice any issues.
That's my concern
That was with M1 HM back in the day below -15F I'd be on a 5w for sure
There’s no problem in your climate with 10w30.
Was looking at some oil range charts earlier this week. It noted 10-30 OK down to 0F. For a margin of safety I would not personally feel comfortable below 10F. I placed some 10-30 in a freezer recently and it was a bit thick at around 0F.
Your engine operates at a somewhat different and higher heat level than 0 F. Plus there's all the stuff about parking away from the prevailing wind direction, under some kind of roof instead of in the open etc. And then there's the pour point of the oil. 3 C / 5 F above the temperature at which a sample of oil shows no movement when held horizontally for 5 seconds. Do you expect temperatures in Cali to reach -39 C or -38.2 F even up in the mountains?
This is Mobil 1 10w30 API SP / ILSAC GF6A
| Pour Point, °C, ASTM D97 | -39 |
I’m also in SoCal, the coldest i experienced w 10w30 was years ago in Big Bear where temps reached a low of 25 degrees. I had a Chevy S10 (v6) at the time, it started up and ran like normal. Your FJ will be fine w 10w30 in SoCal
17F I'd hate to tell ya ain't cold
People were starting up old V8 boats back east with 10w40 in really cold weather back in the day. The most expensive oil back then is nothing close to the cheapest "store" brand oil available today.
We were in big bear last weekend and it was 14F!
If you are anywhere in Cali that goes to -25 F or lower never mind the -30 or lower pour points of even dollar store engine oils ..
Down to -20C; 10W-30 seems to be fine. When you get below -20; 10W-30 makes for a lot harder starting. It’s crank-tested to -25C; so technically it’s good down to that temp, but I’ve noticed things get strained at -20C.
That said, in Cali you aren’t coming close to those temps, so def use it up, it will work well!
That said, in Cali you aren’t coming close to those temps, so def use it up, it will work well!
I’ve used PP full synthetic 10w30 below zero in of all things a cobalt.
Starts, likely wears the engine out faster, just be very easy on things the first 5 minutes of operation.
From what I’m told a modern full synthetic 10w30 behaves differently than 80’s Dino juice. I didn’t notice a slow start even at -15F but as stated probably not good for the engine.
Starts, likely wears the engine out faster, just be very easy on things the first 5 minutes of operation.
From what I’m told a modern full synthetic 10w30 behaves differently than 80’s Dino juice. I didn’t notice a slow start even at -15F but as stated probably not good for the engine.
JHZR2
Staff member
Good enough for 1980s diesels…
Something that gets forgotten is those “5” increments actually mean something (0w, 5w, 10w). They mean they test ok in 5C increments. That’s a 9F increment.
10w is good to lower than people think, and a 5w isn’t THAT much more insurance; it’s no magic bullet.
As a side-note for those who like anniversaries, it’s amusing to note that the SAE started working on winter ratings in 1933, and testing in the winter of 1933-34. So it’s the 90th anniversary of the start of the SAE winter ratings.
10w is good to lower than people think, and a 5w isn’t THAT much more insurance; it’s no magic bullet.
As a side-note for those who like anniversaries, it’s amusing to note that the SAE started working on winter ratings in 1933, and testing in the winter of 1933-34. So it’s the 90th anniversary of the start of the SAE winter ratings.
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