I have a 90 Ford Mustang with a carbed 306 with a T5.

I got completely swindled on buying it, it repeatedly overheated on the way home and I may be stuck with it.

Anyway, the problem is that the car overheats after a few minutes of driving. It does not overheat at idle, at least it does not overheat as rapidly as when it is driving.

There are no leaks, the coolant reservoir and large aluminum radiator are full, no hoses appear to be collapsing and the fan spins like it is supposed to.

I removed the thermostat and it cooled down significantly, but it still began to overheat after about 15-20 minutes of driving. This was not bumper to bumper traffic either.

Any ideas on what the problem could be?

 

maybe the head gaskets are on backwards. Its easy to do. Or maybe its overbored to much.

 

Why would it overheat if it were over bored? Also how would I know if the HGs are on backwards? I am new to V8 engines.

 

ur head gasket(s) are blown or in a worse case scarnio ur head(s) are cracked or warped

 

They are blown? I have no smoke or leaks.

 

I would flush the rad..napa make some really good stuff in a blue plastic bottle..also check the clutch on the fan....going to a 3 core rad about 135.00 will help a ton and use a mr. gasket 185 stat

 

The thing is that with the thermostat removed, it idled for about 15 minutes with no change in temperature. There are no leaks or smoke.

 

so is the t-stat opening? im not too technical but from what ive read.. if it dosnt open or meet operating temp it will not cool properly

 

Are you getting anti-freeze flowing into the overflow tank? What are your other signs that it is overheating? If you are only going by what gauge is reading maybe just your gauge.

 

didnt even think of that.. the stock gauge is junk

put a thermo light on ur t-stat to get an accurate reading