94 Overheating....Blown head gasket or faulty thermostat???

[foxbodymike]

I just recently got a 94 GT. The guy I got it from said it had a blown head gasket. Normally if you have a blown head gasket, there is water in the oil, smoke coming out of the exhaust pipes, and the motor overheats fast. In my case, the motor doesnt really overheat that fast. I can run it hard for around 10-15 minutes before it goes above normal on the engine temp guage. The car doesnt smoke, has no water in the oil, and runs fine. When you open the radiator cap and the reservoir cap, it seems like the water has a brown residue, maybe from rust inside the radiator. When the motor starts to overheat, you can pop the hood and the hose going to the water pump will be really tight. Could this possibly be a clogged or faulty thermostat?? The brown residue could have clogged it up. Or is it a blown head gasket?? Please help because I am really puzzled.

 

[True 5.0]

Are you losing fluid?

 

[foxbodymike]

Yes and no.... today, the temp guage showed a little above normal so I pulled over the car and the water in the reservoir was kinda boiling. Then, a couple hours after this, The reservoir was empty with the brown residue in the bottom, and the radiator itself was low.

 

[True 5.0]

I would guess you have a blown head gasket or a cracked head. The water in the reservoir wasn't boiling. It was the exhaust gas bubbling out.

 

[foxbodymike]

So you dont think it is the thermostat???

 

[True 5.0]

I doubt it. There is a test that can be done to the coolant to check for dissolved exhaust gas to confirm.

 

[foxbodymike]

How would I go about doing this test your talking about. I would really like to be 100% sure before I make this decision

 

[True 5.0]

I know most radiator shops can do it. Go here for more info:
Head Gasket or Combustion Leak Test Procedure (Gasoline Engines Only)

 

[94argomustang]

mine has the same prob did you fix it