You should also check for oil in the cooling system. Had a C-series behave just like this. Oil-water heat exchanger was leaking. After some days of using it like that it burned up number 1 for good.
After cooling down and pulling the engine I had to use a big hammer to get the piston to move out of the bore.....

AlpineRAM

 

Sounds normal to me. Both of my trucks do the same. Higher egt's = higher coolant temps. Run it slower and the temps drop. FYI one is a 5 speed and the other is an automatic.

 

Same here...sounds normal for a 190* T-Stat! Especially with the weather how it's been. Your 'new' HP level will make it happen more quickly.

If I ran 2-3 passes at the track, back to back.... when I had a 190*, I would be around 220*. Cooled down quickly if given a chance.

Does not happen with 180* T-Stat.

RJ

 

There's definately no oil in the coolant. My buddy just had his oil cooler leak into his coolant system so I definately know what to look for (talk about one heckuva mess).

What should I look for in the coolant system? Fins are nice and clean, no obstructions.

 

where do you find a 180* thermostat? - I need one

 

Are the core tubes clean (inside)? Not plugged up I hope...

Thermostat good? (test it)?

Cap good (test it)?

Fresh coolant / water mixutre?

If this is all find in dandy then you creating more heat than the cooling system can dump. So now how much fuel are you dumping (EGT)???

 

Cummins PN 3967195

This quote from 'Haulin in Dixie' , who tows very heavy, is what convinced me.

"The latest thermostat that I purchased for mine is the smoothest that I have had. It does take a mile more to warm up, but is really nice on the temperatures. Mine in high humidity, air full blast, 94 degrees, heavy loads, has not yet gone over the half way mark on the gage. It is the thermostat that Cummins lists for (updated) the RV275/CPL2080 engine but is a direct replacement for the OEM on the Dodge engine."

RJ

 

Another thing you can considder is that coolant doesnt not cool as well as water. You live in South Texas. YOu can cut back on the coolant and run more water in the system. Just have enough in there to keep things from rusting up.

I would pressure test your system over night (Say around 13-15 PSI...what ever you cap is rated for). See if it holds pressure. Prob not the issue...but its good to check. It should hold fine if you got no issues.

Turn you truck on and let it run for a bit. Then have someone shut if off. See how long the fan spins.....it should not spin for very long if much at all. Clutch should have a fair amt of drag when cold. if you can spin it by hand and get it to turn about 1-2 turn fairly easy....might be clutch time....but you dont see these go bad much really.

Look at your weep hole on your water pump. Look for signs of leaking.

Might be time for a flush....i heard of someone flushing their system with dish washer soap for about 15-20 mins and worked great. Might give that a shot and pre-mix some coolant and water.....use more water than coolant....refer to the jug for mix.

Get that 180* t-stat....and just run the thing year round....you are in South Tex man...you got EGT's to warm the truck up! haha......

My 2

 

EGT's aren't an issue as you'll soon see in the vid I'm about to post. Don't know if yall can see the temp gauge move up (road was bumpy and it's hard to hold a camera at 100mph).

 

http://media.putfile.com/Temp-Gauge

Yall might have to open it full size and squint to see it but it does move. I'll see if I can't get a better one when it's hotter outside. It was only in the 80's when I did this video.

 

Have you guys thought about the fact that when running a bombed truck, the engine may heat up faster than the factory designed the fan clutch for? I mean the fluid in the clutch hub has to get hot enough to couple the clutch and engage the fan to engine speed. I noticed my fan kicks in on the downside after pulling a big hill after the temp has creeped up to the high side of the white zone. Just a thought.

 

I'm thinking that's what's happening is that with my EGT's being so high, it being so hot outside, that the cooling system just can't keep up. I checked my fan clutch today and it's dang tight. I can barely spin it a 1/4 turn before it stops.