Very cold at elk camp... synthetic oil in my TJ?

In weather that cold, a synthetic is definitely a good idea since it really does flow much better in extremely cold conditions. I'd run 5W-30 synthetic in those conditions. Maybe even 0W-30 synthetic would be a good idea for those cold starts. I don't run synthetic due to its added cost and in my temperate climate, I don't see a whole lot of REAL benefit to synthetic over a high quality mineral-based multi-weight oil. But I sure would run synthetic without a second thought if I lived and drove in an extremely cold climate like you do. :)

Jerry

Synthetic is better at these temps but I wouldn't worry about 'only'

-15F, the Jeep will tolerate it easily. (different story around the -25 to -35F range!) Make sure you have fresh oil (5w-30). a good battery, and get it to operating temp quickly (drive it, don't idle it for 20 minutes)

I'd be more c> It sort of breaks my heart to start my Jeep up at elk camp every year... it's

The idea here is that the amount of cold engine wear with the engine sitting idling (think low oil pump pressure) is worse for the engine than if you start to drive right away where you get some additional pump pressure to move the thickened oil. Obviously, the thinner the oil stays at low temps the better. Obviously, you take it easy until the oil comes up to temp. Also, remember that the oil is slower to warm than the coolant, so don't just go by the temp gauge in the dash (unless you have an oil temp gauge too)

Even though -15 is not all that cold, you could use synthetic oil, especially one with a smaller first number, such as Mobil1 0w40, and this will stay far thinner than even 5W30 conventional oil.

-Fred W '98 TJ Sport

Ignore the curmudgeons that insist we drive our cars the way our fathers (and their fathers) did in the days of straight 30 weight motor oils that turned to taffy at 10 below.

The intent is to get the engine through the low operating temp as quickly as possible. you want to get the engine out of limp mode (rich mix) that can wash down the walls. It's not as bad on the FI vehicles, it can be brutal on a carb vehicle. You also want to spend as little time as possible turning the eninge over with thick oil.

Normal very cold weather start up procedure is to start the engine, fast idle for one to two minutes, start driving gently (no more than 20 to 30 mph) Keeps the engine rpm up in the 1500 to 2000 rpm range while still providing some small load. Once the temp gage starts showing a reading, you can push it down a bit, just no freeway driving until the gage is well up on the scale. A lot of times the automatics are the limiting factor. Put them in drive and nothing much happens until the friction in the toque converter warms things up enough to get oil pressure to the clutches.

Generally the carbed vehicles are good to -25, FI goes to -35. Both take some pretty healthy batteries, thinner oil, and recent tuneups. My personal record is -35 in a windswept parking lot in Thief River Falls, MN (Think Arctic Cat test track) at 6:30AM in January

BTW: When it's -35 out, it's 35 degrees warmer > Can you please explain, why do you drive it to heat it up quickly? > Thanks in advance

I'd always understood it is because they are scared they can't get them started again.

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

Well, I've also seen over 200 truckers stalled in parking lots and beside the road in 800 miles of westbound I-80 because they were so cheap that they thought they could get by with #2 diesel in cold weather. And the truckers that left their engines running, they would stall on the on-ramps or 1/4 mile onto the freeway when the sludge they were burning hit the injectors. Nary a one on eastbound, guess those northern guys have more respect for their equipment. But what do I know about big trucks?

As for FI automobile eng> Again you want to put a cold engine under a load? If this is such

OK, then let me ask THIS: I'll be towing a small trailer with maybe 600 pounds of stuff in it up with me, and it's a 6-hour drive, and it's possible that it could even be fairly warm on the way up there. Last year it was probably 65 F most of the way up there; the cold weather did not hit until opening morning. Would 0w40 still be OK to have in the TJ for the long, mostly uphill drive TO elk camp, with the trailer in tow?

-jeff

The oil has two numbers.

The 0W is how thick it acts when cold. The 40 is how thick it acts when hot.

The outside temperature has no real bearing on this.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Handywired wrote:

Fred W. proclaimed:

'nother issue is that if you idle the vehicle until the engine is warmed up, your suspension, axles, transfer case, and transmission are all still cold. Moving off right after the start and simply taking it easy warms all the pieces up together.

L.W. (ßill) Hughes III did pass the time by typing:

Oddly enough most auto trannies have a heater (of sorts). They run fluid through the radiator and when you block the rad off to warm the engine it will start warming tranny fluid.

It's the diffs that turn into jell-o. That and the transfer case. I prefer simply to not be in that cold of an environment. :)

Of course the best part of being up where it's cold is the first few miles of thunka, thunka, thunka, thunka, thunka, till the tires warm up and loose that flat spot.

Especially on my '71 VW camper! Not "thunka, thunka," but "WHOMP, WHOMP!"

Paul B.

01 XJ

Ya bill, you get a lot of -35 degree days in February, don't you? :-)