Took the truck out this weekend and the temp was spiking kind of randomly. As of right now I do not have the fan shroud on and the radiator is 3" higher than stock.

I plan to put the shroud back on and flush the system. But I'm thinking its the thermostat sticking shut?

Any other ideas?

 

I'd put the shroud back on first and see what happens.

 

Does it have to sit higher or is there no room to lower it?

 

Can't lower it because of the steering box.

 

The thermostat could be the problem, they aren't expensive to replace. You've probably considered a shorter deeper radiator to accommodate for the decreased spaced

 

Do you have air in the system? How hot is it getting?

 

Shouldn't be I haven't drained it or anything in a long time. It was spiked all the way when I first noticed it in traffic, check gauge light came on. But after that I kept an eye on it on the trails and didn't let it get above 3/4 of the way up the gauge.

I'm gonna start by trying to get the radiator as clean as possible inside and out and put the shroud back on before I mess with the thermostat.

 

might be packed full of sand and mud. if you drain the fluid you might as well just replace the thermostat. its cheap and easy at that point.

 

Has it been running a normal temp before this ?

Does it do it just in town or on the highway too ?

 

Have a look at the coolant reservoir. Is the coolant dirty and perhaps foamy? If so, there could be combustion gasses getting into the coolant. This will cause temp spikes and overheating.

 

Two reasons there is a shroud...
1. Keep people from putting their hands in the motor when it is running and losing their hands to the fan
2. To direct the air flow properly to the radiator, without it; the air goes everywhere except where you want it to