I drive a 2003 F-350 with the 6.0L PSD at work with the automatic transmission. With the temperatures at -40ºF, the engine temps remain fairly low. We didn't have such a noticable difference with the 7.3L PSD that the new trucks replaced.

The speed limit on the road here at work are 50% 35 MPH and 50% 45 MPH. In drive at 35 MPH, RPM's are about 1500 and at 45 MPH - 1200 RPM. Even with a winter front covering the radiator and oil cooler, the engine temps are fairly low at these RPM's. We have been either running in tow mode to remain out of overdrive and RPMs hit about 1800 RPM, better engine temps, but not ideal for a warm cab. Running in 3rd, it is about 2100-2200 RPM and more warmth.

Fuel is here is paid for, so mileage is not an issue. It is about an hour and a half drive with no stops (I mean none at all, no lights or intersections) for most drives. What does everyone think about driving at these higher RPMs (I know they are not too high)? How about worries about damage to the transmission running in 3rd gear?

How about increasing the engine temps mechanically. What is the stock thermostat, should we upgrade to a higher temp thermostat?

Thanks in advance for everyone's input.

 

Being from Florida, we don't have much experience with that problem, but just for info, how warm will it run? Does the thermostat open? Stay open? I see a lot of OTR trucks with part of the radiator covered to get the temps up. I doubt the higher reves make much difference. That engine isn't really making any horsepower at those revs and therefore not much heat.

 

On follow up, the engine temp guage indicates about 1/3 up into the normal range in drive (1200-1500 RPM), but the heater does not blow very warm. When the engine is running at least 1800 RPM (perferably greater than 2000 RPM) in tow mode or third gear, then the engine temp in the middle of the normal range.

All drivers of our 10 trucks are reporting the same low temps and cool heaters, so it is not a stuck open thermostat. Unless all 10 truck thermostats are stuck open

 

Cover about 1/2 of the radiator with cardboard and see what that does, then add or subtract until you reach the desired temp. just like nascar racecars, the less air going thru the radiator, the less it cools.

 

Judge,
The winter front I stated in the first post, covers 100% of the radiator and oil cooler already. The weather is just COLD. Ambient temp of -40ºF and -86ºF with 45 MPH windchill factor. I don't know if the windchill factor affects inanimate objects, or is just for humans. The powersteering is even very sluggish after driving for anytime on a straight-away.

Just looked up windchill info, the model is based upon human skin and exposure of a persons face. The truck should only be experiencing -40ºF

 

Too darn cold for me!!! i think the wind-chill just affects living things, but under -40 I'm not sure it matters. Coldest I've been is about -15 or so hunting in Canada, and that was plenty. i guess that's why i live in Florida. It got cold here last weekend. 35 F. Almost froze.

 

But I read elsewhere some ppl use a 203* thermostat. I don't know if it will help because I don't think the 195* is opening now. There are other ways to make the engine build heat, a device that acts like an exhaust brake will make heat. I can't imagine what -40* must be like.

 

Do not know if I have an answer... the answer... or just a stupid idea???

Can you plug in at night... or do you already? Plugging in would allow the motor to start easier and warm up quicker. Starting from a totaly cold motor takes more RPM's and longer time to warm up.

I live in KC and it takes 5 - 10 miles to warm up all the way.

I heard from my dealer that Ford put in a larger radiator and tranny cooler. It works, but maybe to good for those of you in the extreme cold. I was told that if I added an aux. tranny cooler to do so after the built in on. He advised that on cooler days, you can actually "over-cool" the fluid and have worse performance. You want to cool it, but not cool it to low.

Just an idea on the plugging in issue... sorry I did not have a real solution.

Good luck,

 

We found the same at -40 or less. The heater only warms the cab (not hot) and defroster doesn't keep up well. Everything was stiff - steering, abs, clutch. We were happy is was starting and running.
(We did the same: cold fronts, plugged in, etc)
Do not know about the thermostat, etc.

 

Twin Tritons: Are you on the North Slope?

 

SavageSam, if the stock thermostat is 195°, it would definately help to upgrade to a 205°. Does anyone know for sure that the stock one is 195°? Summer temperatures don't really get much over 70°F up here, so overheating shouldn't be an issue.

Beachbumcook, yes we do plug in. We use block heaters, oil pan heaters, and battery heaters and don't have any problems starting. Glow plugs don't have to cycle as long as the 7.3L did. The truck sometimes idles for 1/2 the day, but we use an auxiliary idle control set at 1250 RPM.

AlaskaPowerStroke, yes I am on the North Slope, Milne Point to be exact.