CTD99

Just curious what the ideal (coolant) temp is for these trucks to run at? Mine typically fluctuates between 160 - 180 degrees, I rarely see 190 or higher even when towing. This past Sunday I was coming back from the sand dunes towing my toy hauler (5-6K#), pulling a 9-mile grade (close to 90 degrees ambient temp), and the temp never exceeded 180 degrees.

Is my truck running too cold? It has been suggested to me that I might see better performance or mileage if the engine was running around 190 most of the time, but I'm not sure if there's any truth to that or not.

Bought the truck used and I doubt the previous owner would even know what a thermostat is, so I assume the t-stat has not been swapped for a colder unit.

Thanks.
Russ

Mcmopar

Mine is the same.

RustyJC

At some point between your truck and mine, Dodge/Cummins switched to a 190 degF thermostat. Mine will run about a needle's width below the 190 degF mark when empty and about a needle's width above the 190 degF mark when towing (we pull a 13,500 lb 36' 5th wheel). It might go a little higher towing on long hills, but the fan clutch will kick in and it drops right back.

Rusty

dsldan

diesels make power with heat, I perfer the 190 temps seems to have just a little more power.

roadranger

I check my engine heat by Exhaust Gas Temperatures.

It runs just as good, and just as hot, with the 180 T-stat in it as when it had the 190 T-stat.

With the 190 T-stat, the fan would kick in frequently when towing. Hardly does it at all with the 180.

I've read that the fan takes 25-30 HP to turn, so I've got MORE power with the 180 T-stat and NOT turning the fan.

BigBlue

Ditto

CoastalDav

When running light, mine sits a needle width above 190. When towing it will get on up there until it blows off enough water to make room for the expansion and will settle down just above 190, maybe two needles widths. Stays right there but is quick to get up again with if you get on a hill for awhile. Fan Clutch comes on and brings it back. I really been wanting to change it to 180 but seems I never get the time to get the T-Stat. All my other diesel trucks ran at 180 with no problems.

Dave