Hello. I am having some problems with my 94 k1500. It will run at about 210 most of the time but other times it will just suddenly jump to 250 then i will coast 500 yards and be fine for a long time. i started checking things when it did it and im finding my top radiator hose dosent have pressure but other times it will. could this be water pump? Did the head gasket and intake, thermostat.
thank you in advance

 

may want to make sure that you have plenty of coolant in it. sometimes the lower level can make the gauge read a little funny

 

it was full. i have no pressure in the top radiator hose. and its flowing in the radiator

 

This happened to me awhile ago, I stopped driving it and looked at what it might be. Turns out i grabbed the wrong anti freeze. Make sure you use dexcool. Make sure your truck uses what ever kind of antifreeze it says to. I had to drain my radiator and fill it all the way back up.

 

Don't mix Dexcool with conventional antifreeze. Dexcool ate my system up and I will not use it. Clean and flush the system and refill with a good quality antifreeze water mix. I would install a new thermostat at this time. Make sure you purge ( burb ) the system to remove all the air. Make sure that both hoses are not collapsing internally.
Before you start the flush and refill pressure test the system starting with the cap. A bad cap will cause you to tear your hair out looking for problems that are not there.

Just a few thoughts...