Hi guys,


I just wanted to find out where everyone elses engine temps sit while towing. Lately I can't seem to pull any hills with my 10K lb 5er in tow without the engine temps running way up. I have an edge box and I tow on power level 2 ( but it doesn't seem to make a difference if I back it down to 0 ) If I hit a 5-7% grade and try to maintain 60-65 mph when its about 75 degrees outside, my engine temps will immediately jump up to 225-230 degrees. My EGT's are only in the 1200-1300 degree range. I have to keep backing out of the throttle because of engine temps, not EGT's. Does anyone else run these same temps? Is it unrealistic for me to think I should be able to pull these hills without the engine running so hot?


Thanks in advance.

I was in 95+ degrees and keeping my truck at 76mph bucking a 35mph headwind going up mountains and my temperature gauge never moved. I had a slidein camper on the truck that is quite tall and has a flat front so it is like driving a 10ft high brick. I am just stock though. My fan would come on now and again but it didn't take long and it was off again. I think you have a problem. I have never seen my temperature gauge move more than a needle width from operating temperature.

I run about the same weight as you (17,500 gross) and pull the passes in Colorado during the summer a lot, My truck usually won't go over the 210 mark but by about one needle width, but the fan kicks on before it gets a chance to build any more heat. I keep my EGTs at between about 1000-1200 max (stock truck) on the big passes. I do have the ZF6 so I'm sure that makes some difference heat wise but not 30 degrees worth. I wonder if maybe you don't have a fan clutch problem. When mine kicks on it could suck a small dog through the radiator and you really hear it pulling air.

My fan clutch is definitely working. It sounds like a B-29 on a bombing run in front of me. As for the temp guage, I have my edge attitude set to also read engine temp. The gauge in the instument panel won't budge off of 195 degrees while the edge shows the temp continually rising. When the edge display hits about 225 degrees, the IP gauge will all of a sudden flip over to about 225 degrees. This makes me wonder if GM has the gauge set up to not show the heat until it can be a problem.

That's interesting. I always hated trusting factory gauges.

I tow a 10K 5th-wheel over the cajon pass and grapevine here in CA. My highest temps with the J/A on level 2 are approx. 216.

I have hit close to 220 with my 10/K load only when pushing real hard with larger than normal tunes. 230 is much higher than I have ever seen with the 75HP tune. Are you reading this on an Attitude monitor or the factory guage?

Who knows what the specs are on these gauges and probes. It could just be the difference between the different gauges and probes. THe attitude isn't that accurate either as it is interpreting the temp from the engine computer. But that still seems a bit hot.

All the temps that I stated are read off of the attitude monitor. I trust that more being that it is a digital gauge. The Duramax only has one engine coolant sensor and it send information to the PCM. That information is then sent to the IP for the gauge readout. This is why I'm baffled about the gauge readings being different from the J/A. They are both reading the same source information.


CMDMAX - The senario that I stated at first, was about 2 weeks ago on the grapevine. It was 11:00 at night so it had cooled down to about 75 degrees, but I was pulling the hill at 45-50 mph with fan clutch fully engaged and engine temp at about 230.

Bowtieguy,


You didn't say so, but I'm betting your truck is 2002 or newer California Emissions. . . in otherwords EGR. EGR adds heat, no two ways about it. The majority of us can pull almost any load up any hill at any tempurature with our LB7s without heating up, but the EGR LB7s do heat up when worked hard, and the LLYs seem to be even worse (until they are EGR disabled).

How about pulling the sensor out,putting it in hot water that you know the temp of(kitchen thermometer),hook up wires & see what both read.Like testing thermostat.

The truck is a 2004 LB7. I hadn't heard about the EGR condition. A friend of mine has the same truck and trailer setup as I do and he doesn't seem to have the same problems. He says his gets to about 208 or so but not up to the temps I'm seeing. I'll research this one some more. I know disconnecting EGR on a gas vehicle can be bad on the exhaust valves due to increased combustion temps, but does anyone know if would hurt a diesel?


My next step is to pull out the sensor and check it for accuracy, but based on my fan clutch opperation, I'd be willing to bet the engine's getting that hot.

I don't know if you have the bugs that we do down here. There is alotof different radiators in the front of these motors. bfore I spent any money, I would wash the radiators out real good. JMO

I have a 2004 LB7, and my temps get up to 230 also, while pulling a 10000 # 5th around Phoenix. It cools down fast after level. I took it to the dealer, and they said no problems noted. I'll be going over grapevine in a few days on our way to Oregon.


Seems some trucks have higher temps than others. I wish some one had an answer.

I have also seen 230 or so going up Cuesta Grade - the steep side - at 103 degrees with a 14k fiver and my foot buried in it, holding about 52 mph. Not sure of the percentage of the grade, but it's definately one of the steepest my truck has seen, loaded or not.

My truck is stock. I'n not worried about that temp at all. Good coolant mix and water wetter in the coolant, 230 is no problem as far as I'm concerned.

It rose to 230 by about halfway up and held steady.

I should also note that I have a billet grille that admittedly probably blocks a fair amount of airflow. However, that climb was the only one I saw on that 300 mile trip that the needle even moved a little bit.

Marc

A diesel engine working at or near maximum egt's will run near maximum water temperture. I bet if you backed out of it and kept your egt's around 1000* to 1100* you will notice a difference in engine temp's.

A diesel engine working at or near maximum egt's will run near maximum water temperture. I bet if you backed out of it and kept your egt's around 1000* to 1100* you will notice a difference in engine temp's.

yeah, but then you couldn't brag about how fast you went up the steep grade with a really heavy trailer http://www.dieselplace.com/forum/smileys/HiHi.gif http://www.dieselplace.com/forum/smileys/HiHi.gif

Jim

I don't know if you have the bugs that we do down here. There is alotof different radiators in the front of these motors. bfore I spent any money, I would wash the radiators out real good. JMO


Early in 02 several owners reported the problem you have. I would take the top cover off the radiators, loosen the top mountings & slightly seperate the radiators so you can see in between them. One owner posted pics & you wouldn't believe the mass of bugs on the one radiator. You can't see them without seperating the radiators a little.They have placed radiators with finer cores in the middle behind the coarser cores & that is where the "bugs stop"


Good luck http://www.dieselplace.com/forum/smileys/Thumbs Up.gif

Pullin out west 2 weeks ago, edge set on 3 pulling the toy hauler and working it 75-78 mph the fan would hit and pull hard but I saw water temp of 240 ish with trans temp of 210, egt's of 1080 via the edge and the outside air of 101 and the a/c lost its cold became cool- 80 in the truck. Now that I'm home A/c works fine and I run 210 , checked the "bug" catcher and it's clean. Must be the 6-7% grades that will heat the truck up fast. Still running the stock Alli with 51k!http://www.dieselplace.com/forum/smileys/Clap.gif

My fiver weighs about 9,000lbs. and mine will go up on long grades in hot weather. I run a 90hp juice on level 2. This usually only happens if I am running in overdrive if I drop to 4th and pick up the RPM's a bit it doesn't pick up as much heat. Just came back from a trip to the Black Hills and Colorado and pulled some big passes in excess of 11,000 feet. Usually only happens when it's pretty darn hot out. Of course I am running the A/C full blast and I cruise at 75MPH.

http://www.dieselplace.com/forum/smileys/Ermm.gifI had a 94 gmc and I put in grill inserts from LUND. After running them for a couple of months during the summer, I took them off to clean them. I inspected my radiator and it looked about as bad as it would without running with them. I took them off and threw them away.

Hey BigdaddyG,


My 5er is a Jazz 2770RK. Our trailer weights are very close to the same. I also pull all hills in 4th.


How do you like your Jazz? We love ours. 1 year old about 10k miles and very few problems.

We like it very much. Ours is almost 2 years old now and very few minor problems also. I have pulled around 12K or more with 2 long trips through the Rockies. Probably been over the continental divide 6 or more times with it.

Just returned from an early elk hunt in Northern AZ. All steel 3 horse slant with 10' LQ. 2 horses and 140 gals of water and the crap for more'n stay. Tipped in at about 14,800# Traveled the US60 up and down from 1200' to 9000' in 105 to 85 degree temps. Never saw the engine or the trans temp touch 200/210. EGTs were from 1000 to 1350 and hugged the speed limit the total trip. Edge at level 2, 4" flowthru muffler in a 3.5" exhaust pipe. The only vehicles that passed me was those I let!!

Hey folks, nothing is for free.


More performance, more heat, (rocket sciences, I don't think so).


What is your EGT, the engine water tempeture is a function of how many btu's are being passed to the radiator, not the engine core tempeture.


Idahofox