Need Help!! '96 Cobra overheating!

[RedTwilight]

Yesterday my '96 Cobra started to overheat and coolant was overflowing out of the resevoir cap . This is the first time anything like this has happened on this car. Normally the needle points between the M and A on the temp gauge. But when it starts cming out of the cap it's pointing the L.
Sometimes it'll rapidly fall back down to the O and R then back up to A.
I know there has been a small hole in the radiator for the past 3 or 4 months but never had a problem. I just kept the coolant full and all has been well until yesterday.
Does anyone know what could be causing this? Could it be because of the leak in the radiator or maybe the thermostat failing? The car doea have almost 120,000 miles on it. I need help fast until I can get my '93 back on the road . Thanks for all the help!
Trinity

 

[punkgt]

sounds like you developed an air bubble in the system. Try refilling and burping the system once car starts to heat up. This can be accomplished by slowly and carefully opening the cap on the overflow tube, just a little, until fluid starts pouring out, then tightening it. I've had this problem from time to time thanks to crappy hoses, never heard of an overheat caused by lack of pressure in radiator, but who knows. I highly recommend getting the leak fixed.

 

[injectedracing]

t-stat, air bubble, or it needs the coolant TSB

 

[bdcardinal]

do you know if your cobra got the fix? the 96 GTs and Cobras had inefficient cooling systems and there is a TSB to replace the radiator and some other components. it might be too late to get it fixed for free. i would definately not suggest slowly opening the radiator cap, and closing it right away, that is probably gonna cause more problems. do a complete coolant flush and run the car at idle until the thermostat opens then turn it off, wait till it cools, and refill the resivour. there is a little cap on one of the hard tubes that has can be opened with a 1/4 drive extension or ratchet. that is another point on the motor where it can be burped, but only open it when the motor is cool.

 

[doogz]

Try burping the system, then a t-stat, then a radiator.

 

[slowyellowcobra]

My 98 cobra just had the same problem about a month ago. Your not gonna like my suggestion, but the cause of mine was a warped cylinder head from being overheated by the previous owner. I would have a triple gas test on your coolant to check for hydrocarbons in the coolant. If there are hydrocarbons present the you are getting exhaust gas into your cooling system causing overheating that will fluctuate as you drive the car around. A warped head is not the only possible cause it could also be a cracked head or a head gasket. i hope this helps.

slow yellow cobra
98 cobra coupe
Eibach springs, tokico illimina shocks
mac cat-back 430 gears

 

[RedTwilight]

thanks for all your suggestions. I know it hasn't had the cooling TSB. But I've never had a problem with it since I bought it in '99. So that should rule that and the warped cylinder head (due to overheating) out. I believe it's the thermo seeing as how it has 120,000 miles. So something is bound to fail. I am also not ruleing out the air bubble! Gonna check today and maybe can find an answer.
Thanks for all your help guys!!!!!!
Trinity

 

[Marine One]

When I called SVT a couple of years ago about the cookling system TSB, I was told that it was too late to get it done for free. I was also told that replacing the factory radiator with a Steeda would basically accomplish the same thing as the TSB.

 

[Darkhorse845]

I hope you find the fix!

 

[RedTwilight]

took a look at it yesterday and it looks like the thermo is sticking.
So does anybody know the factory thermostat temp? Would it be ok if I went with a 180 degree thermo. Someone said the Cobra might not idle right if I went with a different temp thermo. So would a 180 temp be fine or stick with factory?
Once again thanks for your help!

 

[bdcardinal]

i think the factory one is 192. you should be fine going with a 180 tstat.

 

[sirhisss]

First of all, get the radiator fixed or replaced. The Steeda unit is not a bad idea. With a hole in the radiator you are wasting your time in messing with other issues of the cooling system.
Once the radiator is fixed/replaced, then fill the system 70 30 mixture and add Redline Water Wetter. Fill the system till full at the radiator cap. Install radiator cap and then remove the port plug on the crossover pipe. Fill here till full. Start motor and let it warm up. Fill the crossover tube as necessary.
Once the engine is warmed up and you have heat in the heater hoses (interior heat is max) then top off the crossover tube, shut motor off and install the plug. This will eliminate all air.

It would not be a bad idea to replace the thermostat since you have 120K miles also. A flush of the cooling system is mandatory at this time since you have to repair or replace the radiator anyway.

You will be fine with a 180.

I also do not have the TSB installed. I have open tracked mine several times in 90+ degree weather without any problems. I do maintain the cooling system very regular through flushing the system and replacing coolant yearly. Sometimes more than once a year.

Good luck!

Drive it like you stole it.