Ok this ones odd, i have heat on minute and the next i dont, the temp gauge on cluster goes to the almost too hot mark, and i lose heat, i keep topping off the coolant also. im wondering if the cap is bad? i dont see any leaks and if it was the intake gaskets i wouldnt be losing coolant this fast, i added half gallon to it last night, and had heat this am just fine for about a half hr, then it got cold, if i rev it i can get heat tho. which makes me think theres an air pocket? any of u seen this?

 

Sounds more like a head gasket.

The lack of heat is caused when the combustion chamber leaks pressure into the cooling system and causes air to get into the system which interrupts the flow of coolant and causes the lack of heat and over heating.

My guess is the truck will have no heat when the gauge goes up close to the red, then the gauge will suddenly go down to normal and the heat will come back?

The coolant loss will likely be from coolant leaking into the combustion chamber and being burned off through the exhaust. If you drive it like this for too long you risk damaging the piston in which the coolant is leaking into as well as other components if left for too long.

 

A simple way to tell if it is a head gasket is take the radiator cap off and top off the coolant, then start the truck and let it get up to operating temperature... watch for bubbles coming from the radiator, if it is blowing bubbles it is likely the head gasket. If there is bubbles you can let it cool back down a bit and run compression tests on each cylinder and if 1 cylinder is real low you will know which head gasket is bad, it is generally a good idea to replace both head gaskets as long as you are under there doing the work, usually if 1 is bad the other is not too far behind.. if the leak is that bad I am surprised it did not set the SES light with a misfire code

 

im thinkin the intake gaskets, very commom issue, its not burnin coolant and its filling my crankcase with coolant.

 

yeah its most likely the intake gasket then, you never mentioned before that you were getting coolant in the oil, how long have you been running with coolant in the oil.. you may have some damage then if you have been running it.. main bearings etc

 

well ive changed the oil twice in two weeks, i put a pf47 on instead of the pf 52 oil filter so i changed it sunday, and lost heat the next day, so hopefully im ok, im a ford tech by trade but i drive chevys, done intake gaskets on everything i own exc my blazer dammit lol!! ive done my lumina, monte carlo, malibu all cars i used to have, well kept the monte thats what im driving until this weekend when i fix the IM
thanks for the comments and ill let ya know what i find

 

ok well keep us posted, hope all goes well with the fix