Overheat under load

[mdatc]

At 65+, 20 psi boost, 1100* EGT, pulling a heavy load, my temps reach the 3/4 temp gauge mark. Radiator, therostat, hoses replaced. At idle and lower speeds, temps are less than the halfway mark. Any ideas???? on what to replace next?????

 

[Philip]

Do you hear your fan kicking on? At this temp it should. Mine kicks on a little above the halfway mark.



The thermostatic section of the fan could be bad.

 

[MMiller]

Does it ever quit going up?



In the rolling hill of iowa pulling a large load mine will run about 2/3 or so on the gauge. The faster I run the worse it is.



I agree with looking at the fan.



Michael

 

[mdatc]

Sounds like fan hub and fan replacement. Ordered!!! Now that you mentioned it - I haven't the familiar 'chirp' on shut down in a long time!!!! Guess I needed a new radiator anyway. I'll have the new fan/hub assembly on in a few days and I'll post the results.

 

[paccool]

Per the D/C manual, that type swing is normal. When towing, mine goes that high when pulling a long grade and after the recent addition of a modified fuel cone, I have to back out of the throttle to keep the temps under control.



I had the radiator cleaned, put in a new thermostat, added water wetter, etc, still does it when towing.



Has your pump been turned up any?



What is the transmission temp doing?



Let us know how the new fan hub works. That may be a problem with mine. I used to be able to hear it turn on, but its pretty quiet now.



Stan

 

[Midnite]

Are you in 4th gear when it heats up like that? Full throttle in 4th gear when loaded and going up a hill *really* heats up the ATF quickly (even at 65+ mph), which in turn will also heat up your coolant.



Mike

 

[steveinaz]

check the ac condensor. mine was full bugs and would not wash out. ended up sitting there with a feeler gage poking passages through the fins for over an hour. water temp won't even get to half now. exhaust temp will get to the back-off point still.

 

[Philip]

For a temp gage to climb on hills is normal. But at 3/4 swing on the temp gage and the fan not kicking on is not normal.



When one of our fans kicks on. You and everyone close knows it.

 

[mdatc]

Never thought about using a feeler gauge to clean the a/c unit. I'll do that. It was running warmer than normal before the pump was turned up. So I stopped fuel mods to work on the over heat problem. Once this is solved, gonna work on getting the EGTs to the back off point!!!!!! Don't know what the transmission temps are doing. Need a recommendation on a good aftermarket transmission temp gauge???? It does get hot, because I hear the transmission aux cooler fan kick on. Least, I think it's that fan. But still in all, nothing kicks on till I reduce speed/throttle below 55 mph and that one fan seems to kick in on when struggling up long slopes at 45 mph with the foot in the floor!!!

 

[Philip]

I have had my engine fan kick on three times in 6 years. But all three times I was loaded on the same hill in the MO state on I44. The temp gage had just went a very small amount over the half way mark when it kicked on. It kicked on for about 30 seconds then right back off.



You under bed fan is the trans cooler. I can't remember its kick on point. I think it is around 180 to 200.

 

[mdatc]

New fan/fan hub installed. 'chirp'on shut down is back and I hear the fan kicking in when the temps get up. Temps still up, but the fan now cools it down within reason. Next I'm going to pop the grill and thoroughly clean the a/c coil. If all else fails, replace the temp sensor!!!!!



Duh, I feel so DUMB!!!! I read the service manual and temps between the 3/4 & hot mark are normal for heavy loads!!!! I'm just not use to seeing gauge readings that high for normal operations.