Very worried.....

[danhercules]

I have a buddy that has a 95 Chevy 1 ton with the 6.5. I took super good care of the truck. In the dealer every 5k. He did have a lot of weight in it and drove a TON of miles. Like 300 per day. Lots of grades. No towing, just very heavy wiht tool boxes and parts. He mentioned it would get hot up the hills. I dont know how hot, but he is very anal, so I dont think it was over 3/4. He always stops when his trucks get hot when he tows his toys.
Anyway, by friend bought the truck 6 mo ago. Has put 3k on it. He was towing and the truck started making a loud noise and lots of black smoke. He took it in, and was told he needs a new head, possably 2 of them, not sure yet. Said it was do to heat............Now, my worries, You may have read that I have put some big tires on my truck and need to get it regeared before I tow my 5th wheel again. I am worried because I got it pritty warm towin once. The 1st time towing with the new tires. I got between the 2nd and 3erd mark over 2/3. I had the heater on, no AC, and was taking it easy, I told myself if it hit that 3erd mark after 3/4, witch is before the red, I would stop. It never did. It was like that for 5 min or so, then I was atop the grade and she cooled down quick.

I am worried I did damage. How long before I know if I did? What is too hot? I do not have gauges, I just ordered some. I am gonna regear my truck if I keep it. I tow a lot. Thanks,

signed, Very worried in CA!!!!!!!!!

[ucdavis]

Hard to say. If your gauge is the stock one w/210 @ 12 o'clock position, & idling @ start it runs @ the left end of the fat mark just to the left of 12 o'clock, the gauge is operating well & @ 2/3 you are showing nicely over 210 degrees. That's not good.
I just did a long trip (~2500 mi) running max weight & gauge never hit 210. B4 the trip I unbolted ac condenser & cleaned between it & radiator. I'll bet you have bugs 'n junk there killing the efficiency of your cooling. This is probably the #1 killer of these engines (failure to clean this airflow space).
Good luck.

[rjschoolcraft]

Prior to all of the cooling upgrades on my truck, I fought overheating constantly while towing. I have over 120,000 miles on this engine (187,000+ on truck) and more than half of that towing heavy. I've had it a lot hotter than you describe and used to run at the temps you describe frequently.

Last summer, I installed the dual t-stats and high flow pump. Removed the radiator and cleaned all the air flow areas as mentiond by ucdavis. Thought that I was in good shape. Towed the camper to SanFrancisco via the Mojave Desert and Sequoia National park. It over heated badly on several occasions on that trip. Boiled out coolant and gage into the red zone. I used my heaters to help and melted the louvers on the vents. Coming back through Salt Lake City, the quick release fitting for the heater hose blew and I lost all of my coolant...had her very hot...gage pegged.

Now I have an intercooler and Kennedy fan clutch with 9 blade 20" fan. Overheating problems seem to be gone. I've put on over 25,000 miles since that summer trip and have seen no sign of any engine problems. I didn't let the temps stay that hot for very long and did many flushes with fresh water to get things cooled back down on at least two occasions on the trip.

I don't think you will have any real problems with what you've described. Obviously, I would rather not have experienced these problems, but I tried to react to them and use all of the tricks I knew to preserve the engine. It seems to have worked. I think you would have to ignore temps in the red zone for many miles before serious damage could occur based on my experience. However, maybe I just got lucky.

[Johnny B.]

The past two summers I towed my travel trailer to Wyoming and engine temps were pretty much between 210-220 sometimes 225 with a good head wind. Two years ago I had the factory temp gauge pegged and a buzzer sounded about a minute before I reached the summit. After cresting the summit the engine quickly cooled down. After this trip I put a Mallory temp gauge on, surprisinly the factory gauge was accurate.I'm surprised how hot the 6.5 runs, I'm shocked to hear some that can't get them above 180-190?

Late in Aug 2003 I added the dual thermostat crossover, I still need the 4 core radiator since the previous owner had replaced it with a two core.

[cruzer]

You're probably OK, but it can happen.

The summer of 2002 I pulled a slide in camper
& car trailer approx wt 8000lbs+truck thru Colorado, no cooling mods and neglected original rad it had a banks exhuast. Engine got hot going thru the mtns. Pegged the temp gauge a couple of times, but no problems during the trip. EGT's stayed in check. Truck had approx 130,000mi on it. 4 months later(NOV) pulling same load 6hrs down south into TN the engine cracked #3 piston. During it's last trip it did not get overheated, but run at 65-70mph. I believe the CO trip took its toll on the motor and the result happened 4 months later.

Now I have cooling mods, new fan, clutch and rad. It is suprising how cool it runs and how much more power I have w/all the mods added during rebuild. I has only gone over 200* once running 180* stats w/same load and going faster thru the mtns of KY & TN. Thanks to TDP and its members.

Everybody will have different experiences & scenarios, you will find when there is a failure there is a good chance it was heat related. When I rebuilt my engine I knew cooling was a must. Do what you have to, to keep them cool, and maintain that system, especially de-bug the rad periodically.