Just got back from a 1900 mile round trip to New Mexico. On the way there I noticed that the temperature gauge started 'creeping' up and then suddenly falling back to its normal temperature. This was at a steady speed of 70 mph pulling our 5th wheel. Wind was a quartering tailwind. As we drove I-25 from Colorado Springs and started up to Raton Pass from the Colorado side it went to just shy of the H (still not to the red though) and then went down to normal operating temperature (express - just as if the thermostat had just opened up). It did this several times more while we were on the trip. This Tuesday and Thursday, driving solo back here in Kansas, no hills, just a fairly level 20 mile drive, I noticed the temp gauge do the same thing albeit not to the higher extreme as when it was under the load.
So, after all that said, here is the delimna. In the 'old' days when I could work on the vehicles (before all the computers and pollution stuff), this activity indicated, to me at least, that the thermostat was dying and needed to be replaced stat. I called my selling dealer and was told that I needed to drop the truck off so that they could evaluate it - problem could be several things and they would need to test multiple items? Local diesel shop told me it was a thermostat. No radiator leak(s), both antifreeze reservoirs are at or above the cold fill lines. I don't see anything obstructing air flow to the radiator nor are the fins bent (that I can tell).
Truck only has 17700 on it so don't want to do anything to void engine warranty.
Suggestions as to what it could be, if not the thermostat?
Thanks.
Ron
So, after all that said, here is the delimna. In the 'old' days when I could work on the vehicles (before all the computers and pollution stuff), this activity indicated, to me at least, that the thermostat was dying and needed to be replaced stat. I called my selling dealer and was told that I needed to drop the truck off so that they could evaluate it - problem could be several things and they would need to test multiple items? Local diesel shop told me it was a thermostat. No radiator leak(s), both antifreeze reservoirs are at or above the cold fill lines. I don't see anything obstructing air flow to the radiator nor are the fins bent (that I can tell).
Truck only has 17700 on it so don't want to do anything to void engine warranty.
Suggestions as to what it could be, if not the thermostat?
Thanks.
Ron