1972 Grande 302 w new thermostat overheating. With smoke coming out of my cool air intake.

[iTzPayDay3x]

What’s up mustang fam,

I just installed a new thermostat as well as the housing in my ‘72 Grande. I had a pretty bad coolant leak so figured it could be the thermostat. My brother and I were working on the new thermostat installation when we noticed the housing unit we were replacing didn’t even have a thermostat, which we found strange.

After the install, we ran the car for a few minutes to get the new coolant running through after we flushed the radiator with water. While running the car, the upper hose got very hot, the lower hose was warm but definitely not as bad as the upper.

We ofc turned the car off then tried to start it a couple minutes later, then smoked started coming out of the cool air intake by the carburetor.

We figured since the car didn’t have a thermostat, we could remove the new one since that may have caused the car similar problems in the past. But then what about my coolant leak? Do I need a new radiator and scratch the thermostat?

Any ideas and suggestions would be very appreciated.

 

[will e]

Greetings and welcome to the forum

First, by leak I assume you mean you could see coolant leaking out of the engine/cooling system. The thermostat is inside the closed coolant system and once correctly installed cannot cause an external leak. They can 'fail' but a failure not 'cause' a leak.

It's pretty easy to install them a bit 'off' of the seat and so when you put the housing on it doesn't seal correctly but this is quickly discovered.

The coolant comes out of the top of the engine pretty darn hot, as hot if not hotter than the thermostat rating. If you were 'flushing' at the same time it would explain the cooler water and cooler bottom radiator hose. Although the lower radiator hose should always be cooler than the top after the engine has been running for a few minutes.

A cheap IR gun can be very helpful to see the temps at the housings and hoses.

It's also possible to install the thermostat backwards. Some water will still flow (causing the upper radiator hose to get hot).

The smoke coming out of the 'cool air intake' is a bit concerning. Was it smoke or steam? Did it keep coming out or did it stop? Did it occur while the engine was running or while you were trying to start it. More details and a picture of your engine will be helpful.

But back to the cooling problem and leak.

Is, or was, there a cooling problem or just a leak? I will focus on the leak because we know it existed. Did it leak A; All of the time, even parked.. B: Any time the engine is running C: A few minutes after the engine is started D: Only after it is turned off. (Or a combination of those).

Can you tell us the approximate location of the leak?

 

[iTzPayDay3x]

Greetings and welcome to the forum

First, by leak I assume you mean you could see coolant leaking out of the engine/cooling system. The thermostat is inside the closed coolant system and once correctly installed cannot cause an external leak. They can 'fail' but a failure not 'cause' a leak.

It's pretty easy to install them a bit 'off' of the seat and so when you put the housing on it doesn't seal correctly but this is quickly discovered.

The coolant comes out of the top of the engine pretty darn hot, as hot if not hotter than the thermostat rating. If you were 'flushing' at the same time it would explain the cooler water and cooler bottom radiator hose. Although the lower radiator hose should always be cooler than the top after the engine has been running for a few minutes.

A cheap IR gun can be very helpful to see the temps at the housings and hoses.

It's also possible to install the thermostat backwards. Some water will still flow (causing the upper radiator hose to get hot).

The smoke coming out of the 'cool air intake' is a bit concerning. Was it smoke or steam? Did it keep coming out or did it stop? Did it occur while the engine was running or while you were trying to start it. More details and a picture of your engine will be helpful.

But back to the cooling problem and leak.

Is, or was, there a cooling problem or just a leak? I will focus on the leak because we know it existed. Did it leak A; All of the time, even parked.. B: Any time the engine is running C: A few minutes after the engine is started D: Only after it is turned off. (Or a combination of those).

Can you tell us the approximate location of the leak?

Thanks for the welcome!

The air intake was most likely steam as it didn't start until I had turned the car off and wasn't black nor had any kind of burning smell....
And it was seated properly as there wasn't any leaks or squirting in that area...

But I also need to mention that the car has a lot of what looks like vacuum hoses that aren't connected to anything, also the intake manifold has a hole on the side that seems like a hose should be connecting it to the valve cover which has a male hose attachment but no hose....and to make things more interesting there is a second radiator in front of the main radiator the has threaded out put, but again no hoses connected to it.

Oh and also there was significant rust in both the radiator and the engine.

I left the car sitting overnight and there were no leaks anywhere. It only leaked coolant once which made me believe it was the thermostat which is where the big leak was under the car. The leak happened after the car was turned off.

I really appreciate the response, this is a very interesting project !

 

[midlife]

Are you filling up the radiator to the very top? It should be just above the upper cross-plate when looking with the cap off. Water expands when it gets hot, and you may be seeing overflow. Normally, there's an coolant overflow bottle somewhere to catch it. Do you have it and is a hose attached?

 

[Spaceman]

Could you post some engine pics? That vacuum hose from the valve cover should be your PCV and connect to a port on the back of the carb.

The second radiator not connected to anything is likely leftover from AC that was removed - mine has the same thing. It's the old condenser.

Is this steam coming from your carb?