6.0 Temp problem

[gixserkid]

I have a 03 F550 with 30K.....I was driving it today with no trailer at 65 MPH and the temp went up almost to the red on the gauge, but when I pulled over the engine seemed to be operating at normal temp...I let it sit at idle for like 15 min and then the temp came back down to normal temp...The water pump is good and so is the thermostat....Any help?

[Hayman]

Sounds like the thermostat is sticky have you ever flush the hole system out?to see how dirty it is it mite be putting crap in your thermostat.

[ShawnCT450R]

I second Haymond! I would flush the system and replace the thermo if it were me, cause it can only get worse. Cheap fix to prevent an expensive problem.

[Betaracer]

Inspect the coolant. I had a cracked EGR cooler and a cracked oil cooler. Oil mixed with soot mixed with coolant was not a desirable combination.

[nontypical]

are you blowing any coolant ? mine started only when i was towing heavy loads and it eventually got to the point where i couldnt go up a slight hill empty before i blew the egr cooler.. just got the truck back 3 days ago but the egr delete pipe is in the near future..

my truck would blow coolant out of the bottle and also visible in the drivers wheel well

[donald scott benford]

see if there is coolant around the coolant reservoir if so may have bad egr cooler that failed when that happens it blows head gaskets and causes engine to push coolant out around the reservoir cap. is under warranty for 100000 miles with u paying a 100 dollar deductible.