96WhiteBuffalo

with the bed loaded high with firewood and towing a 14' trailer with about 2 tons of firewood on it. The roads were snow covered for about the first hour, but after that it was smooth sailing, and I do mean smooth. I ran about 60-65 mph on cruise control and at times on the steeper hills the turbo went up over 30 for a few seconds as the beast labored to maintain speed. I was ready to kick it off, but it always came back down.

I have enjoyed this truck a great deal, but the reason I bought it as opposed to a 1/2 ton gasser was for short heavy hauling--15-20 miles. This is the first time I took a longer trip and it really ran like a champ. Now I better quit bragging or it will break down on the way home.

BTW, when I left home Sat. morning it was -3. After I drove about 200 miles I fueled up, and my white-bottle Power Service was about like 30-weight oil.

One other thing--since my truck is so cold-blooded you can hardly stay warm in the cab, I partially blocked the radiator (but not the intercooler) with a political sign left over from November. It raised the lower end of the temp range about 10 degrees, but it never ran hot at all.

klx650a2

In order to get some efficiency out of the motor (and not wreck the compression rings), if its that cold, I'd block the front of the grill off.

96WhiteBuffalo

the radiator. I think the trans cooler is up front, too, and I want that thing to run cool. I do not understand why the rings would be affected.???

Not doubting you, just don't get it.

Number47

diesel engines like to run warm 190-195ish when its cold the rings are brittle and the tolerances are really loose. make it possible to break a ring and have lots of blowby

96WhiteBuffalo

That is why I blocked the radiator. Is he saying he would have blocked all air by covering the grill, and that this would have insured higher engine temps? If so, I get it now, if not then I don't. Sorry to be so dense.

infidel

If you need to stay warmer and it's below zero out use the recirculate position on your climate control.
All the other positions pull in cold outside air sometimes not warming it enough though the heater core. Recirc will cook me out of the cab on a -30F day.
One more 12 valve advantage, the newer trucks don't have a recirc position except for max A/C.

96WhiteBuffalo

Good call, but my truck won't drive you out of the cab on recirc at zero. I just would not drive it at -30 without Arctic gear. I have thought for some time that I have some kind of blend door or heater core problem. There is a difference between the "cold" and "hot" setting, but it is not as great as you might wish. I have never done the inlet/outlet temp test on the heater core and I guess I will have to get around to it some time. It works kind of okay, but the colder it gets outside the less heat you seem to get.

Number47

sounds like its time for a heater core

nickg

You never posted what your actual engine temp was. Is it up to 190* when cruising on the hi-way??

96WhiteBuffalo

Yes. It cycles from ~160-190, maybe a shade higher, then the thermostat opens and it plummets back down to 160 or so.

CamperAndy

I am going to go with partial blocked heater core, combined with a very slow thermostat. The heater core flows water all the time from the back of the block, back to the pump inlet. This minimises stagnation in the radiator, block and the system in general.

The wild swings seem to be due to poor flow in the system, resulting from little to no mixing of the cooled pump inlet until the thermostat swings open then in rushes a very cold slug and the cycle starts over.

I would try to back flush the heater core or replace it along with a new thermostat. Even when it is near zero F my temp swing is only 6 or 7 degrees (192 to 185) the first time or two the thermostat cycles then it is a steady 190.

nickg

at a steady speed/load your thermostat should be holding a fairly steady temp. You should not see huge temp swings. I'll bet if you replace the thermo, you'll have a huge improvement in heat in the cab. and improved engine efficency

96WhiteBuffalo

I have had the truck 3 years. Replaced the thermo twice (second one a
cummins) and had the heater core flushed once. The temp still cycles, and the heat is still mediocre. Blocking the radiator partially helped the heat a moderate amount.

nickg

My experience has been,(I dont believe the cummins thermo is any different) that some thermostats right out of the box, act as you describe, its not like they are calibrated, The only thing that is calibrated is the hole in the center, thats what limits the flow of coolant thru the engine, when and how the wax pellet opens the "door" is a whole nother story. I found the absolute worse brand was Moto Rad, they are found in most parts stores here in Canada, junk. I had one particular car (dodge shadow) I went thru 4 yep 4 thermo's they ranged from taking for ever to heat up to running the temp to redline and back to cold. It was a weekend at the time and the only place that had any was Canadian Tire. after that I found I had the best results with stant brand thermo's. All I can say about your plunging temp is that it is a thermo issue. I did not want to pay 123$ from cummins for a new one so for 30$ I installed a Stant. my old thermo would not get over 180* and ran typically around the 170* mark (it was a 190* rated thermo) my new one gets up to temp and I see 190-195* depending on engine load, even after idling for a while the temp gradually goes down, start driving and it goes back up to 190* and stays there, especially if driving steady.

Maybe other Dodge trucks have this problem, I dont know. But I believe at least for the 01 there is an updated 190* thermo, maybe it addresses the "plunging" temp issue. When it's cold here -30*C and lower, I have the rad completely blocked off the temp still works in its desired range. even at temps as warm as -5*C it still wont overheat

This has been my experience after 22yrs as a mechanic working on everything from a lawnmower to a Leopard tank, does not mean I know anything, just sharing my results

96WhiteBuffalo

The attached thread I found during a search contains a post by infidel that touches on this point. I questioned this cycling of temp guage readings when I first got the truck and was told it was normal.

The post by infidel quotes a dodge tech bulletin or some such authoritative source that says the cycling is normal.

https://www.dieseltruckresource.com/...ne+temperature

BTW, I do not think this cycling necessarily applies to 3d gens.