[7caratkid]

I just replaced the radiator, thermostat, exspansion tank and cap, every hose possible ex. The truck runs excellent until I speed up to over 50 miles an hour. I can let idle and drive around town but as soon as I get on the highway the guage jumps up GRRRRRRRR. What could this be???? I'm pretty sure the air is out of the system. I just don't get it, any help would be much appreciated..thank you

 

[Dan_UK_1984]

I'm sure you searched already `8) But this topic was covered a couple of days ago, check this thread out and see if there is any extra info there to help you out....

viewtopic.php?f=2&t=36391&p=282341&hilit=overheat#p282341

 

[linuxfreakus]

what about the water pump?

 

[linuxfreakus]

Also may want to check the catalytic converter... could be clogged/blocked causing excessive back pressure... or maybe even the fan, or belts, but since you only have problems at higher speeds, I don't know if belt slipping would be worse at speed...

 

[03rangiemark]

Also may want to check the catalytic converter... could be clogged/blocked causing excessive back pressure... or maybe even the fan, or belts, but since you only have problems at higher speeds, I don't know if belt slipping would be worse at speed...

Sounds much like a bad fan clutch. But it does also have an electric fan in front of the rad., not that I can say it would do the job if the fan clutch on the belt-driven fan was bad.
If you turn the fan by hand (motor off, of course) do you feel a healthy bit of drag? If not, it could be the clutch.

 

[Dan_UK_1984]

Also may want to check the catalytic converter... could be clogged/blocked causing excessive back pressure... or maybe even the fan, or belts, but since you only have problems at higher speeds, I don't know if belt slipping would be worse at speed...

Sounds much like a bad fan clutch. But it does also have an electric fan in front of the rad., not that I can say it would do the job if the fan clutch on the belt-driven fan was bad.
If you turn the fan by hand (motor off, of course) do you feel a healthy bit of drag? If not, it could be the clutch.

With a bad fan you get overheating the other way round, when driving the air gets forced through the radiator so you don't rely on the fan, if you o/h whilst stuck in traffic its a bad fan...

D

 

[delSilencio]

water leaks ? thermostat again ?! waterpump? right coolant or did you mix wrong coolants and now the system has viscous fluid ? Any white pudding like parafin when you stick the finger in the expansian tank and scratch in the edges

oiltemeprature ? oilpump?

 

[delSilencio]

when the watersystem is overheating you should also have problems with the automatic gearbox ( not enough cooling with the inline oilcooler) when hot, try manual shifting mode and look if it works only until the third gear.

 

[SGW]

Are you actually overheating, or could it be the gauge malfunctioning.

Stewart.

 

[azjulian]

when did your overheating problem start ?

Was it after replacing the thermostat etc or before?

If it was before - then you should run a test that you can get at a local parts store for side products of combustion in the coolant.

let us know when the overheating started and we'll help resolve