Heres the problem.

All of the sudden the heat in my car will turn cold and then my temp gauge will start to spike up, sometimes i have to pull over for a while and then its fine, other times i will suddenly have heat again and the temp gauge falls back to normal.

I just changed the thermostat and its still doing it!

Any ideas??

thanks,

matt

 

check to see if you are low on coolent and if theres coolent in your oil. might have a blown headgasket or a headgasket going out

 

Yes sounds like it's low on coolant. Don't just check the level in the plastic bottle. With the engine cold, open the radiator cap and the radiator itself should be full to the top. A blown headgasket will often push the coolant out of the radiator, or let it get sucked into the combustion chambers (which causes a lot of white "smoke" that smells like antifreeze from the tailpipe).

 

The oil looks perfectly fine to me, however, the antifreeze does look a little crappy. I had the headgasket blow in my old dodge daytona and it definately isnt anything near that! I am going to check the level in the radiator and the coolant resevoir and get back to ya!

thanks for the help so far!

matt

 

ok so it seems to be holding the temperature better now that I have filled the resivoir up to the top, and topped off the radiator itself. My new question is how much pressure is supposed to be in that upper radiator hose? My hose is hard as a rock by the time i am done driving it! Seems like maybe to much pressure to me?

I am getting a little hissing from the cap itself also (maybe due to this pressure???)

Any more help would be great!


thanks,

matt

 

It's normal for pressure to build up, you shouldn't have any hissing though. Again wait for the engine to cool and take the radiator cap off and inspect the rubber gaskets in the cap. If they are cracked, buy a new cap.

 

ya i was just wondering. I figured some pressure had to build but i didnt realize it was that much.

 

If you start the engine when it's cold with the radiator cap off, as the engine warms you can actually watch the thermostat opening and closing by the flow of the coolant. If the cap is off, it will allow any air to escape as it passes through the system. Caution though, as the coolant heats it begins to expand and will overflow, so you need to monitor when it is getting close so you can put the cap back on before you lose any coolant. If you have a head gasket that is showing wear, one of the possibilities is it can pressurize the cooling system by letting compressed gases from the cylinders blow by into the water jacket. This will happen before you show signs of water in the oil because the small amounts of water will burn off during combustion before it can leak into the oil. More white smoke (vapor)or longer than usual duration after the car has warmed up is tell tale.