So after a pretty long restoration that included a complete engine rebuild I drove my 442 around for the first time and it is getting hot and boiling over. The car sat since the late 70’s and I DID NOT have it boiled or rodded out. However last night I was getting about 20 degrees drop between the inlet and outlet. My highest cylinder head temps with the infrared gun was at the center exhaust ports on the head of about 250 degrees. Back and front of the heads were 205. I don’t have the rubber flaps on the radiator or core support either. . Going to have the radiator pulled out and checked and rodded out if need be. Not sure that’s my issue with the temperature drop I’m getting though.

 

Put a actual temp gauge in the cooling system, then see what happens. All the shrouding endures the air coming in the front of the car goes thru the radiator. It may help.

 

Can you elaborate on this? Maybe there isn't actually a problem, but you need to post more info to be sure.
How hot is it getting?
And is it actually boiling over, or is it just purging a bit of coolant?
If you don't have a recovery tank, the coolant level needs to be at the fill line on the end tank, which is a couple of inches below the top of the radiator. If it was filled to the top, then the expanding coolant would puke out, making you think it's boiling over.

 

Kenneth- I don't believe a '67 has a recovery tank reservoir but I could be incorrect. I know I don't have one on my '71.

NotDads442- I just kinda sorta went through this very similar scenario until I mentioned it to another member & they said - check my radiator cap. Hmmmm, I thought.
Well, after some modest examination of the radiator cap - the big gnarly spring which holds the cap into position at the radiator sleeve opening was fine, the gasket looked fine. The funny thing is this - that piece of metal at the very bottom of the radiator cap, was pretty tight against that piece of rubber when I pulled the cap off the radiator. However, after about 1/2 hour (the time it took me to buy another $6.00 radiator cap and return home) I noticed that piece of metal at the very bottom of the radiator cap has the 'valve' stem inside of it which actually opens & closes and it was completely hanging limp and doing nothing at all. That valve stem extends up into the center of the radiator cap. Reviewing the new radiator cap I just purchased I noticed that 'valve' stem has a spring inside of it which acts like a plunger to keep it extended up into the center core of the radiator cap. I installed the new radiator cap and have not had an issue with slight boil overs - which I'd prefer to say was more or less 'venting'. My boil overs were occurring while working on the car when it was remaining at idle for extended periods of time - maybe once I experienced some coolant venting after driving but it was idling for a long time before that. POINT: try a new radiator cap - they're inexpensive and designed to maintain the pressure you need to achieve optimal cooling. Mine is a 16lb radiator cap.

 

I would get an inexpensive mechanical temp gauge and hook it up temporarily or permanent with a volt meter and oil pressure gauge. We need to know what temps its getting too. Other things that will cause an engine to run hotter is retarded timing and a lean fuel mix. Pointing the infared at the exhaust ports won't tell you much unless there is a bad cylinder.

 

A good electric fan will cure your problems if your radiator is functioning correctly. Get it checked out at a good radiator shop. dont waste time and money on a "hi-volume" water pump!been there -done that with my 67s

 

Check to make sure your thermostat is opening, Remove radiator cap. Run car at high idle until up to temp and look for flow through radiator. Also after running car up to temp shut off and check to see if fan clutch is engaged. Hope that helps

 

67s had no overflows.

Boiling over is a violent, hot event. Venting too much coolant is not.

If you have a YUGE difference between radiator hoses, like one is cool and the other nuclear, the thermostat is stuck. The thermostat locks out the upper hose, so, if it is not hot (damn hot), then the thermostat is not opening. The upper hose should be HOT, the lower hose should be hot-shower-warm. Nothing is going to be cool at operating temp, the fins of the radiator cannot pull the temp down to ambient unless the car is shut down and making no more heat.

I would confirm thermostat and cap. I would get a mechanical gauge and put it in the intake port for the idiot light. A stock engine needs no electric fan.

 

The upper hose was hotter than the lower. The infrared gun had a 20 degree difference between the two. The car just slowly gets warm and when I stop it pukes out the overflow hose. Sitting idling it really gets hot fast. I put in a new thermostat and new water pump as of last week as the old water pump was leaking. The cap is genuine Delco from super cars unlimited. When I pulled the rad yesterday I did notice the coolant is getting nastier as if all that sediment from the bottom rows of the radiator since the car sitting from the late 70’s is coming out. I should know in 10 days as the radiator shop in Spokane is a little backed up.

 

I recommend flushing out the entire system. The rust particles will eventully compromise the seal on the water pump shaft

 

Were it me......and assuming that there is an overheating issue and not just dumping out excess coolant....and even still, if you took the time to rebuild the motor, I'd take the time to make sure the cooling system was up to snuff...

If I wasn't sure when the last time it was done.....I'd flush the system and replace the hoses and the thermostat. Easy, cheap and should be done periodically anyway.

My experience has turned out to reinforce the notion of find the problem and fix it rather than guess and throw parts at it.....and in terms of cooling system issues, it comes down to either capacity or coolant flow and an old, corroded radiator doesn't help either situation. For what it would cost to have a radiator shop look at it, unless originality is an issue, you could probably just purchase a new one that probably outperforms the original one when it was new. An aluminum radiator with 2 rows of 1" tubes for 150 bucks worked wonders for me...

just my .02....your mileage may vary

 

A puking radiator out the overflow is usually because its overfilled with no head space. We need to know actual operating temps in both cruise and extended idle.

 

If the car does not have AC and you have a new intake manifold, it could be a missing restrictor under the heater hose nipple in the passenger rear of the intake manifold. Without the restrictor too much water flows through the heater and not enough flows through the head and does not cool the engine enough. I had this problem years ago. Found the restrictor in my old manifold and reinstalled it under the nipple in the new manifold. Problem solved.

 

Now you have me paranoid.... what does this fitting look like?
My car has always ran hot & i have no idea if the rear fitting was changed.

 

I thought the restirction was built into the heater hose nipple? I recall Octania posting pictures of non-AC heater hose nipples with a 1/4" hole in them, similar to the hole in the base of the vacuum control valve on AC cars.

 

That is what my 66 manifold has.

 

Yes. But in my 1966 it was a separate plastic disk that sat below the nipple. This is the nipple that the heater hose connects to on the back of the intake manifold on the drivers side.

 

So there is a well below the threaded area where the disc would sit and be trapped when the nipple is screwed into place?

 

Exactly.

 

My radiator was 80% plugged. Had it recored and all is well now.