Hi guys, I have a problem and I'm stumped. When driving my temp gauge goes up and down as if it's overheating. It happens randomly. I thought there was air in the system so I ran it without the radiator cap for a while to let it bleed. For the past couple days I've been letting it warm up and then opening the cap slightly to let the air escape but it seems to never run out of air...

 

I opened the radiator cap today again this morning. There was some pressure built up from last night and air escaped. I'm letting it idle right now with the cap off.

 

Does your car have the coolant bleeder screw on the engine?

 

I know there's a drain bolt, are you talking about that?

 

What year is the car?
Did you turn the heater all the way to hot when running the car?

 

It's a 97 gsr. Yes, I moved the slider to fully hot. I read that if the bubbles keep coming it might be a blow head gasket...I hope it's not that. I checked the dipstick and oil looks fine. Dirty but not milky...

 

There is no bleeder on that car. Is the overflow bottle filled to the line?

 

there should be the little breather valve on the water neck coming off the head. keep opening and shutting it until you get all the air out

 

No there is not.

 

when i had a civic it was doing the same thing, I would turn the heater on and the temp would go down, hope you find the solution ..

 

friends del sol done this same thing.. he had a warped head.

 

OP, if you think the head gasket is compromised, run a compression or leak-down test.

 

you can use a coolant pressure tester and if it does not hold pressure there is a coolant leak.

Does the upper hose become hard after just a few minutes being started?
if so then you might have a head gasket issue pressure building in the cooling system.

But if you install the pressure tester on the rad and pressure builds then it is head gasket!

 

my moneys on the headgasket. same problem with my dc.

 

Yeah, it's filled to the line.

I would drive and the temp would go up. When I let off the throttle for a bit the temp goes down. The heater hose busted today so there might be more air in the system?

Is the head gasket an easy fix? Can I do it myself?

 

If you replace the head gasket, make sure you check the head to see if it's warped, especially if the car has ran hot.

 

Do you think that the heater hose could have been cracked and leaking before it broke? I would replace the hoses and check again. A head gasket is neither cheap or easy to replace.

 

It might have had a tiny hole. When I noticed that it busted it had a rip near the clamp about 3/4" on the side where in goes into the block. I'm about to do a coolant pressure test to see if it holds pressure. Thanks for your help guys!