Engine Temp High on tow

[jwdeeming]

I tow a 4-horse trailer with my 2001. It has the auto transmission and a "towing package", but my engine temp is getting too high on WOT hill climbs.



I am surprised at this because with the Mopar Guy BHF air filter, and a BD 4" exhaust turbo-to-tail, my EGTs NEVER go over 1400, and I really have to work hard to get them up above 1300.



Any theories why the EGTs would be good, but the engine temp (according to factory gauge) climbs up to the red zone? It doesn't do it rapidly, and it takes a long climb to make it happen, and outside air temp doesn't affect it much, at least between 60 to 90 degs.



I should mention that these are high altitude climbs (Colorado mountain passes, usually). Coolant fluid level is normal and I always get it under control before it boils over.



Any theories?

Thanks,

JimD



P. S. I don't have the sensor installed for my transmission temp gauge yet, but if my transmission fluid was running hot, would that be "pre-heating", so to speak, the air before it gets to the engine radiator?

 

[B.G. Smith]

First time I went up that way mine overheated on the pass at Eagles Nest NM. I spent several days in Questa but before I left there, I replaced the thermostat. (I tool the old one out and placed it in a pan of water on the stove, when the water heated, the thermostat opened but the rubber seal on the valve stayed in the opening) I went on to Colorado and crossed Monarch Pass on the way back, no more overheating since. There is a transmission oil cooler on the rt. side of the engine, I believe the fluid goes through the cooler in front of the radiator then through the cooler on the engine. Some people feel that the transmission cooler might heat the engine but I have not had that problem. I tow a 31" 5th wheel. bg

 

[DMcGalliard]

High Temp

I had the same problem pulling my 13k fifth wheel. The problem is the thermostat, there is service bulletin. Changed to the 180 thermostat and can climb any hill with the air on and no temp increase to speak of. The problem is that the thermostat is not releasing water to the radiator. The radiator has the capacity to cool if it gets the water.



Prior to the change mine would heat up on a hard pull, past the right peg and I would turn the air off or back off and it would cool down. Never heats up now.



Truck is a 98. 5/3500/4x4/4. 1/auto/va/boost mod and elbow/BD Vb and tc



Hope this helps

 

[MGire]

Same thing happened to me this summer pulling Douglas pass on highway 139 in Colorado. Steep grade, switchbacks, 10 to 20 mph mostly second gear on & off the throttle. transmission temp eventually hit 300 degrees plus, then the coolant temp went up and held at 205 - 210 degrees. Thermostat and fan were both working. The same thing also happened in stop and go traffic in Farmington, New Mexico. Hot day first and second gear no air moving through the radiator except what the fan could pull. Saw 300 plus degrees from the transmission measured in the output line. Coolant hit about 195 - 200 degrees. Am now looking into a aux transmission cooler, but will double check that the fan clutch and thermostat are working properly. The output line from the torque converter (where the transmission fluid is the hottest) goes to a heat exchanger in the engine first (dumping a lot of heat into the engine, dump enuff heat from the transmission into the engine and the coolant temp will go up) then goes to the cooler in front of the radiator then back to the transmission.

 

[DMcGalliard]

Over heating

Hello



Another thing I have noticed, is get your transmission in lock-up as soon as you can. I have BD torque lock and it will hold the transmission in 3rd for a long pull. Keep your rpms above 1500 and the truck will pull the barn down. For real steep pulls that you have to keep your speed down, keep the transmission in 1st. It will actual cool down pulling in first. 2nd has too much TC slippage which equals heat.



We were recently in Vermont pulling my 13k fifth wheel, they have lots of 10% hills. If you have enough ground speed you can get over them in third lock-up. I shift to second then to first as the going gets tough.



I have the BD valve body and Low stall TC the I am very happy with. I have been pulling the 13k fifth wheel at 30psi boost with no problems. No down shift from overdrive on any Interstate.

I have 10k miles on the up grade.



I like Bill K's second gear lock-up and his new TC. The second gear lock-up will save many trannys if used properly. If the BD

goes I am going to Bill's VA and TC.



davem

 

[BPINE]

FYI I have found that our trucks don't have the cooling capacity to keep them cool when the egt's are held at 1100 or more for long periods. I have tested this on many trucks and they are all the same.

 

[lhend50]

Maybe I am just lucky, but I tow a large 5th wheel and I tow alot and I have never had my coolant temp go above 190. My exhaust temps have reached 1300 and still the coolant has stayed at 190 or slightly below. I have a 96 ram and it still has the original thermostat

 

[jwdeeming]

Thanks for the replies. I'm due for the 30k transmission fluid change so when I'm in the dealership, I'll ask about any service bulletins on the thermostat.



And, points are well taken on the torque converter lockup issues. As soon as I have some spare lunch money, and can find a reliable installer in the Northern Colorado area, I'd like to go with the DTT gear.



JimD

 

[TowPro]

I had a problem where the temp would start to climb while towing over 55mph or hills. I did the same test as BGSmith and found my thermostate was only opening 1/2 way. Enough to cool an empty truck, but not enough flow for a loaded truck.



The TSB I remember said something about the temp was going up and down all the time so they revised the thermostate.

Originally posted by B. G. Smith

First time I went up that way mine overheated on the pass at Eagles Nest NM. I spent several days in Questa but before I left there, I replaced the thermostat. (I tool the old one out and placed it in a pan of water on the stove, when the water heated, the thermostat opened but the rubber seal on the valve stayed in the opening) I went on to Colorado and crossed Monarch Pass on the way back, no more overheating since. There is a transmission oil cooler on the rt. side of the engine, I believe the fluid goes through the cooler in front of the radiator then through the cooler on the engine. Some people feel that the transmission cooler might heat the engine but I have not had that problem. I tow a 31" 5th wheel. bg

 

[roadranger]

I've got a slide in camper at 11 ft. 6 in. tall, and pull a trailer, for a GCW of 19,500. I've gone up Wolf Creek Pass (e'bnd) and Monarch Pass(w'bnd) on VERY warm days with the EGT's at 1150, and the temp rides about 1/4 in. above the center line on the gauge.



Must be the 6 speed... .

 

[Wade Hogg]

I have noticed when towing up or downhill, hot or cold, heavy or light, my engine temps remain the same. never changes even when loaded with 15,000 lbs. maybe you guys are just driving too hard.

 

[MGire]

Thinking about what BPine said about EGT, I was at between 1100 & 1150 for almost 10 min. My dad who was ahead of me (stock 96 except for walker muffler & no cat) never saw more than 900 on his EGT and 190 on coolant temp. Something to think about.

 

[Wade Hogg]

Ooops, i forgot to mention that i have the Horton Fan clutch. it makes a big difference. many questioned the expense for the fan, but as it may never pay for itself in HP, it helps in the piece of mind aspect. Cooler engine temps and cooler tanny.

 

[Strick-9]

I'm with BPINE on this one. If I pull at 1200° for extended periods (i. e. >5 minutes), the water temp will eventually come up.



You are just making more heat than the cooling system was designed to handle for extended periods of time.



I've seen it on three different trucks. I do live in Texas, so that isn't helping matters.



-Chris

 

[MGire]

Talked to Bill K. at DTT, he suggested an aux. cooler in the output line before it goes into the engine. In my situation he said the best thing to do would be to reduce the transmission fluid temp. as much as possible before it went into the engine, to keep as much heat out of the engine as possible. He also mentioned this is not the standard setup he usually uses. Normally he puts his aux coolers behind the front bumper in series with the stock cooler. I probably won't do this until the spring just before school is out when we go camping again.



Mike

 

[DHatfield]

My temp towing around the good old midwest the water temperture gauge never gets over one needle thickness above 190 degrees even when towing the Jeep. I did however on my way back home from California towing my Jeep and trailer (6000 lbs) over the pass on Interstate 80 just east of Salt Lake City, UT did get my temperature up to an all time high of 205 degrees (one needle thickness below 210 degrees), but I guess towing at 76 MPH up the moutain pass in 6th gear with lots of passing everyone while towing uphill, 1100 degree EGT's, with 90 degrees ambient temperture may of had something to do with it. It sure pulls good though as I was never down to the flooor yet .

 

[musclefixer]

Ok, here goes... ...

I just got back from opening day at the Salton Sea here in Ca.

I'm pulling about 6500-7500# of T/T. It was about 98-100 degrees today coming over the Palm Springs pass.

Whenever I pull a grade, with temps above 85deg. the truck heats up to about 210. I have put in a new 180 thermostat, I'm not driving in OD, and I'm driving about 50-55 mph.

I already had the dealer change the fan clutch because it wouldn't go on until about 220 deg. This time (first time towing since fan clutch replaced) the damn thing didnt even turn on!

It got hot enough to make the idiot light turn on, I then slowed to about 40mph before the thing would cool down some. This is usually in 3rd. I did have to downshift to 2nd for a little bit.

The last time I took the truck to the dealer, they put a dent in it... You think I want to take it back??? Besides another (3rd) thermostat, and flushing the radiator, what the heck do I do???

This truck has heated up since I've had it new. Thought it was just the way I drove, who knows, it may be I just have to slow way down.....

Thats no fun indeed. .

Jesse

 

[DMcGalliard]

Still may be thermostat

Hello to Musclefixer,



I know you have changed the thermostat, I would take one of your old thermostats and fix it to be fully open or remove it and use a large o ring for a seal and try the same pull.



Your truck should not be hot unless there is a blockage. I pull a 5 wheel twice the weight you are talking about in od with the air on, mine never gets hot except when the thermostat fails. Make sure the transmission is in lock-up. Mine has gotten warm on a long pull in third.



98. 5/3500/4. 1/auto/4x4/7800#

 

[Barry]

"The truck has heated up since new" has a red flag waving. STOP suffering with the truck! Look in the back of your owners manual, there is an 800#. Dial it everyday and in a polite but firm manner insist that they fix your truck. SOMETHING is wrong with your truck and the sooner you address the problem with the proper people, the sooner the problem or the truck will go away. There are remedies in place for chronic problems, you just need to push the right button... ... ... Good Luck!

 

[musclefixer]

It only really heats up when pulling grades or driving up long uphill stretches like Azusa canyon road up to Big Bear. Since I REALLY HATE taking my truck to the dealer, should I do all the thermostat and coolant myself before having to take it in?

Thanks for the encouragement guys... ... ...

Jesse