1965 Mustang with 302 Engine Overheating

I just recently bought a 1965 Mustang with a 302 non-stock engine. I've done a little bit of work to it, replaced the thermostat, oil change, etc. but nothing major. I'm now trying to nail down an overheating problem but I'm having a bit of a problem. The water pump appears to be ok, no leaking or noise from it. There is this weird thing that occurs, though, that is somewhat puzzling.

With the engine cold, after sitting a few days, I decided to have a look. I removed the radiator cap and started the engine. Almost immediately the water started pushing up to the top of the radiator and flowing out the overflow line near the radiator cap entrance. I pulled out some of the water using a towel so that the water level would drop a bit and the water continued to push up and out the overflow.

What could cause this? Again, this is even before the water started to warm up...

Thanks!

-Samson

Could have an air pocket pushing the water up. Your cap should seal that whole until it gets too hot/overheats.

Yea, I'm wondering if the radiator cap might be rated too low - I believe it's a 13. But, I still think the engine is overheating, running up to about 220 or so before I stop running it. That seems a bit too much for that engine. Maybe I need to have the carburetor tuned. I'm hoping it's not the head gaskets :(

Thanks!

Do you have a shroud?

Do you have a shroud?

I do have a shroud although it is a bit short - maybe the fan is too far away from the radiator?

This is a silly question, I know, but I figured I'd ask anway ... which way should the fan be blowing the air? At this time it appears to be blowing the air away from the radiator towards the engine - I assume air flows through the radiator as the car moves, correct?

yes. The fan should be pulling air thrue the radiator towards the engine.

almost sounds like the rad is piped wrong. make sure the pipes are right.

what year model is the 302? .. is it possible that it has a later model reverse rotation water pump on it?:uhoh:

There is suppose to be a 2" spacer on the fan, maybe it is too far away.

could be the radiator flues are stopped up....might need to take the radiator to a radiator shop and have it flow tested..with it pushing water out as soon as you start the car it sounds like a restriction somewhere.. or else the wrong rotation waterpump installed on the motor..

There is suppose to be a 2" spacer on the fan, maybe it is too far away.

he is saying it pushes the water out as soon as it starts.. even when cold...a fan spacer wouldnt make any difference to that problem

he is saying it pushes the water out as soon as it starts.. even when cold...a fan spacer wouldnt make any difference to that problem

I do have a shroud although it is a bit short - maybe the fan is too far away from the radiator?

Did you read that post? 2" spacer! Of course that has nothing to do with the water coming out:screwy:

I just recently bought a 1965 Mustang with a 302 non-stock engine. I've done a little bit of work to it, replaced the thermostat, oil change, etc. but nothing major. I'm now trying to nail down an overheating problem but I'm having a bit of a problem. The water pump appears to be ok, no leaking or noise from it. There is this weird thing that occurs, though, that is somewhat puzzling.

With the engine cold, after sitting a few days, I decided to have a look. I removed the radiator cap and started the engine. Almost immediately the water started pushing up to the top of the radiator and flowing out the overflow line near the radiator cap entrance. I pulled out some of the water using a towel so that the water level would drop a bit and the water continued to push up and out the overflow.

What could cause this? Again, this is even before the water started to warm up...

Thanks!

-Samson




One of your water lines may be clogged up or your radiator. I used to have a similar problem