87 GT t-top

I have an 87 gt mustang and i am new to the ford world. I just installed a rebuilt 302 and it overheats within minutes of starting to drive. It is fine idling but as soon as i put it under load it overheats. I have flushed the radiator and block. took the stat out and still no good. I just put new head gaskets on so i dont think that is the prob. Any help would be appreciated.

19stang88

Check your fan and fan clutch. If youre fan clutch spins freely, its time for a new one

86 5.0L

well you took the thermostat out, a step in the wrong direction. You didn't put the gaskets backwards or crooked, blocking the coolant passages? routed the serpentine belt correctly?

1990lxhatch

Is it puking out coolant or really overheating. You need to be able to recognize the difference because they are diagnosed in completely different ways.

If the engine runs fine indefinitely at idle but pukes out coolant when you get in the throttle - you are not overheating. You are getting combusion pressure in the cooling system or you have one hell of an air bubble in the rad/block/heater core.

Bubba 95SN

Had this happen once. Bottom radiator hose has wire inside to keep from colapse. Wire rots and when engine is reved up hose will suck shut(collapse) will idle all day and never get hot. Do this -look at bottom radiator hose while engine is at idle- rev engine up watch for hose to hold form or if hose collapses. Bubba

87 GT t-top

yeah im sure it is overheating and not puking it is definately boiling over. havent checked the hose yet tho could be possible.

ryppdlm

Are you sure you have a reverse rotation water pump? Make sure you put the thermostat back in.

87 GT t-top

yeah im sure it has the reverse rotation pump i bought a new stat todat and radiator cap guess i'll get a lower hose tomorrow and see if it helps. i am a manager at advance auto so its not hard to get parts

87 GT t-top

still overheats new radiator cap new lower hose and new stat.

19stang88

Make sure your shroud is not hitting the fan, preventing it to circulate air. I had the same problem. My fan shroud sat to low and prevented the fan to rotate. Check while the car is on