8.1L COOLANT TEMP

DennisH · May 17, 2002

Drive a 2001 3500 Dually CC, 8.1L/Allison 5sp/4.10. LOVE IT! (Am a "reformed" Dodge 1/2 ton owner) Will be towing a 9000# max weight Jayco travel trailer very soon. Under no-tow conditions, whether cold weather or hot, the radiator coolant is a consistent 205 degF. Is this about par for an 8.1L? I also have a '98 Astro Van with a 4.3L and it always runs at about 175 degF. Am concerned (but onlyjust a little) about the coolant temp of the Dually when under towing conditions. If 200-210 degF is about the norm for regular driving (local and expressway), I guess I'll stop worrying. All fluids are topped off, and vehicle was purchased new in Dec 2001.

Thanks very much.

Shaners · May 17, 2002

Welcome Dennis!!!

I think you are in the "normal" range for todays GM engines.

I towed my Jayco 314ss (about 8000 lbs) with my 6.0L on a 90 degree day, and my engine temp stayed very consistant... I was able to get my tranny up to about 195 degrees on a long grade though... (it still had to go to 260 to overheat so no worries).

Enjoy your new truck and enjoy the forum

gandolphxx · May 17, 2002

Drive a 2001 3500 Dually CC, 8.1L/Allison 5sp/4.10. LOVE IT! (Am a "reformed" Dodge 1/2 ton owner) Will be towing a 9000# max weight Jayco travel trailer very soon. Under no-tow conditions, whether cold weather or hot, the radiator coolant is a consistent 205 degF. Is this about par for an 8.1L? I also have a '98 Astro Van with a 4.3L and it always runs at about 175 degF. Am concerned (but onlyjust a little) about the coolant temp of the Dually when under towing conditions. If 200-210 degF is about the norm for regular driving (local and expressway), I guess I'll stop worrying. All fluids are topped off, and vehicle was purchased new in Dec 2001.
Thanks very much.

Welcome to the board, I have the 8.1L and run 190-195 as consistent as the cheesy temp gauge is - yours seems a tad high.

CMNTMXR81 · May 17, 2002

A) our gauges aren't always the most accurate

B) GM runs them hot on purpose for emissions reasons.

The 205-210 degrees that the new truck runs is right on par with B above. I'd question your 4.3 in your Astro. Have you had it since new? Otherwise, someone has put in a 180 degree thermostat which is readily available for the 4.3. Otherwise 4.3's (at least all the ones I've owned) run in the same 205-210 degree range stock.

DennisH · May 18, 2002

Thank you all for your inputs. Very much appreciated.

For CMNTMXR81: Interesting about your comments for the 4.3L in my '98 Astro van. Have had it since new (55K miles on it now) and I was surprised at how "cool" it always ran. Just had a new radiator (and a whole bunch more front end items following a deer strike) installed and it still runs about 175 degF. Interesting that with two separate cooling systems, it still runs same. Glad to know that the 200-210 range for the 8.1L is "normal."

Thanks again to all.

CMNTMXR81 · May 20, 2002

I would be ecstatic that your 4.3 runs at 175. I know all mine have always been well above 200 (just like the 8.1) and all the ones I've ever worked on have been 210 degree thermostats. I cooled them down by putting a 180 degree thermostat in which may very well be likely what happened to yours from the factory as a fluke.