Engine Overheating or Something Else

[jjstahl3]

I have 160000 miles on the motor and don't have a lot of history on it have driven it for a few years with no motor work needed

I don't drive it much but a week ago on the way home temp went from 188 to 220ish is a few minutes then back down to 188 made the drive home and didn't drive it for a week took it around the block and did the same thing. replaced the thermostat as I thought that might be the problem- drove it today with the same temp fluctuation only drove around the block.

any thoughts what could be going on?

 

[n8thgr8]

you didn't say what kind of truck you are talking about

 

[jjstahl3]

96 discovery

 

[jastutte]

sounds like an air bubble. try bleeding the coolant.

 

[WaltNYC]

sounds like an air bubble. try bleeding the coolant.

+1. But keep a close eye on your coolant level.

If you are losing coolant that suggests head gasket and at that point it is super important to stop running it hot.

 

[discostew]

I would check all the normal stuff. But since you say it will start to get hot then cool itself back off, I would look at the fan clutch.Check to see that it doesnt wobble on the shaft. But also look at the backside of the radiator for fins that are rotting away from the core tubes.

Are you sure its not just what type of driving your doing? Are you getting up over 30 mph and that's what makes it cool down? If you keep burping air from the cooling system and more air gets in you probably have a head gasket problem.