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1999 cobra overheating

i3adidas

Member
Feb 20, 2009
28
0
ok i took the car out today and it overheated and i had my turner hook up and it said 250 degrees and the temp was reading under half way. i think my thermostat is sticking cause i could only drive 15 miles. does anyone know if the temp sensor goes out alot and is there one for the computer and one for the gauge? thanks
 

FirstWorldProblems

TCG Elite Member
Staff member
TCG Premium
Sep 6, 2006
70,459
80,158
Crown point, IN
take out the thermostat and see if it fixes it

ok i took the car out today and it overheated and i had my turner hook up and it said 250 degrees and the temp was reading under half way. i think my thermostat is sticking cause i could only drive 15 miles. does anyone know if the temp sensor goes out alot and is there one for the computer and one for the gauge? thanks

Did you change anything before driving it? Why not?



it's pretty simple to diagnose cooling system problems. take thermostat out, then run the car with the cap off for a while, make sure coolant is full and you can see it flowing through the radiator. After a couple of minutes any air in the system should be out, put the cap back on and see if you still have a problem. I'm willing to bet that will fix any problems.

If not... check to make sure that the fans are turning on when the car is at operating temp, considering it's cold outside i don't think this will be your problem. Because of the outside temp, you may have to let the car sit at idle to heat up enough to need the fans.

Do all of this BEFORE driving another 15 miles....letting your coolant reach 250* isn't something you want to do often.
 

i3adidas

Member
Feb 20, 2009
28
0
i made sure all the air was out before i drive the car. someone told me that the computer reads different then the gauge. i put in a after market thermostat in may and someone said they can cause problems so im putting the stock back in. and the fans in my car always run even when the cars not warmed up. they do turn off but not much.



Did you change anything before driving it? Why not?



it's pretty simple to diagnose cooling system problems. take thermostat out, then run the car with the cap off for a while, make sure coolant is full and you can see it flowing through the radiator. After a couple of minutes any air in the system should be out, put the cap back on and see if you still have a problem. I'm willing to bet that will fix any problems.

If not... check to make sure that the fans are turning on when the car is at operating temp, considering it's cold outside i don't think this will be your problem. Because of the outside temp, you may have to let the car sit at idle to heat up enough to need the fans.

Do all of this BEFORE driving another 15 miles....letting your coolant reach 250* isn't something you want to do often.
 

i3adidas

Member
Feb 20, 2009
28
0
ok im going to replace the thermostat tomorrow and i was reading something about drilling a small hole in the top so i can bleed the system easier and it wont cause vapor lock. and does anyone have a diagram to show which way the thermostat goes in im should i have it in right but i just want to make sure thanks kevin
 

99 Stangbanger

Phantom Fury
Nov 22, 2004
1,705
0
What Temp T stat do you have? I wouldnt go any lower then 180. Really should stay at 190 unless you have a blower then maybe a 180 and tune for it.

I have not really looked at my Tstat on my 4V cobra but I recall seeing the holes on the 289 ad 302 engines.. Also have seen people drill 3 holes to help the cause like you mentioned but again that was not a modular engine. Maybe no difference but not sure.

Like someone mentioned above.. The wrong cap or a weak/ leaky cap will cause what you have described. Pressure testing it can eliminate possible causes.

Is your overflow res working like it should? I know there is a sensor in that that gets stuck and will cause issues also. Should take it out and clean it.

Oh and btw.. I dont have a diagram and have not opend my 4v Tstat but I recall 289-302 facing forward.
 
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