Bad head gasket?

[88stang88]

Replaced the Water pump in Feb of 2010, Replaced the thermostat in September and again in Dec, Replaced the Radiator with a stock replacement in November. System works properly as far as flowing and thermostat opening and closing and radiator is not clogged nor leaking. The problem is once you have properly gotten all the air out of the system and you start driving you go about 30 miles and then it shoots a bunch of coolant out of the overflow tank. Is this caused to a bad head gasket letting in exhaust?

 

[BlackVert]

could be

 

[Chythar]

30 miles is not enough time for the coolant to heat up that much, so a bad head gasket (or cracked head) is very likely. If you pop the radiator cap and let the car idle, do you see any bubbles coming up through the open radiator neck? If so, you've definitely got exhaust pushing into the coolant.

 

[88stang88]

Kind of what I thought it would be. Good thing I had plans to put heads on once this cold weather breaks. Might end up going thru the motor since I am pulling the heads. We shall see.

 

[fordtech28]

Did you change the radiator cap? And are you using a standard cap or the one with the pressure release handle

 

[88stang88]

Changed the cap and have a new pressure handle one.

 

[fordtech28]

I've had issues with the ones with the pressure release handle

to verify if its a blown head gasket do a cooling system pressure test

Also do you see the fan turn on when the coolant is overflowing I dont want to diss you but I had people tell me their cars are overheating and I have to ask if they hear the fan turning they say yeah without seeing if its actually on

 

[88stang88]

Yes the fan comes on just fine.

 

[Adam95GT]

Are you 100% sure your t state is opening? But yea a cpt /leakdown is your next step. If you don't have either a standard compression test might give you some insight

 

[88stang88]

Yes the t-stat opens. Whenever you have enough coolant in the system (prior to it evacuating itself) the heater works,fan kicks on normal everything works right. Then you start driving and like I said about 30 miles later it evacuates itself via overflow tank.

 

[1987LXragtop]

I think 30 miles is plenty to heat the system. I just did my driver side head gasket. Getting coolant into the cylinder and fouling the plug so unburned fuel dumping in. Good sign of a bad gasket is that I got pressure in the radiator in a couple minutes and the coolant was ice cold. If youre getting pressure in there quickly when cold, then I would suspect head gasket.

 

[Zero Signal]

If you have an air compressor, definitely do a leakage test first. Pick up a leakage tester form Harbor Freight (doesn't have to be a good one) and pressurize the cylinders, one at a time with a good 100psi if you can and look for bubbles in the bottle or girgling sounds in the head.

Try to get that fixed before you blow out the water pump gasket like I did and have to change THAT too

 

[88stang88]

Well as it stands it is sitting until some nice weather comes so I can just replace the heads/cam/intake and go thru the bottom end...tired of dealing with the crap this winter

 

[1987LXragtop]

Agreed there. Even in my garage I can only get it heated up to 40 degrees inside with the kerosene heater on full blast. Its just too cold and snowy outside.

 

[88stang88]

I think we hit 49 degrees one day with a kero heater in my brother garage...he even has a new thermal garage door too...just balls cold out