We are having a pretty hot summer out west and while towing up a long grade yesterday the temp got up to 227F and the fan was on. My combined weight is 23k. I shut off the AC just to help it out. The guage says the red is 245. Am I safe on these 100 plus degree days?

 

With the 190° thermostat the max allowed temp from Cummins is 225°, so with the 200° in the 4th Gen's I would guess the max allowed temp is 235°.

What gear/rpms?

 

I love how these new trucks run hotter when they're so much more "efficient"

When the HG let go a couple weeks ago in my 2010 I was running 230* cruising down the freeway....every time I slowed down to 2 lane road speeds she'd go up to 245-255*. I saw 276* before I finally made it home and got it to the dealer. The harder I ran it, the cooler it ran. That was roughly 30K gross

I'd say you were still OK, but it shouldn't run that hot with no more weight you have.

IMHO,
Chris

 

I think they bumped the thermostat temp up to increase "efficiency".

 

I've heard the same thing....


sounds like burning more fuel to pollute less to me....

Chris

 

Now that i have a digital guage I watch the temp carefully while climbing. As soon as that fan comes on the temp drops quick. So would you say 240 would be the highest before you begin to panic?

 

What do you consider panic?

Chris

 

Probably headgasket damage..

 

Hmm lets see...

Define panic. I can do that.

1. Get a helmet.
2. Put on helmet.
3. Hold on.
4. Panic



I swapped to a 190 thermostat. Havent seen any higher than 205, but the heaviest Ive pulled since the mods is my camper, bout, 11k loaded up. So, not really heavy.

 

Then your guess is as good as mine. These things are time bombs for head gaskets I guess. Before the gasket let go, I never saw over 220* in the first 70K miles.

Chris