should the water in the radiator boil at all?

[freak]

Just went out for a drive. The radiator is not over/under filled but I hear/see an occasional "glug glug" after I shut down and look in the radiator.

[Mitch//pa]

No it should not boil...you could also be hearing the coolant / water making its way back down one or more obstructed / restricted tubes.

[redmodelt]

On the other hand the Model A is a thermal-syphon system with water pump assist. After shut down the engine temperature goes up because the fan,car and pump no longer is in action. As the temperature goes up there is still water movement between the hot engine and somewhat cooler radiator and you will sometimes hear the glug-glug. The glug-glug does not mean it's boiling, but pretty warm/hot.

[1crosscut]

Stick a meat thermometer in there and see what the temp is.

[G&N Farms]

Originally Posted by 1crosscut

Stick a meat thermometer in there and see what the temp is.

Running, what should the temp look like ?

[freak]

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Originally Posted by 1crosscut

Stick a meat thermometer in there and see what the temp is.

I did. 217F.

[tbirdtbird]

that qualifies as boiling

time to check the cooling system thoroughly

you don't really wanna be over 180

its not even summer yet

BTW check timing to be sure you are not retarded...a retarded motor will run quite hot

[C26Pinelake]

Obviously you know water boils at 212 degrees F ! Wayne

[Y-Blockhead]

Originally Posted by freak

I did. 217F.

Is that after you shut it off or when it is running? The temperature will increase some when it's not circulating, but that's HOT!!

[Mitch//pa]

Radiator time or slowly cook the motor

[Benson]

Originally Posted by redmodelt

On the other hand the Model A is a thermal-syphon system with water pump assist. After shut down the engine temperature goes up because the fan,car and pump no longer is in action. As the temperature goes up there is still water movement between the hot engine and somewhat cooler radiator and you will sometimes hear the glug-glug. The glug-glug does not mean it's boiling, but pretty warm/hot.

Very true that Model A uses thermo-siphon system for cooling.

I will mention this one more time.

1. If the radiator is only filled up to the top of the radiator tubes as many folks insist on doing ... the thermal siphon action can not occur after the engine stops because of the air lock at the top of the radiator. There is no way for the coolant to circulate so it boils at hot spots.

As the hot water rises to the top of the radiator it is stopped by the "airlock". The water can not circulate inside the radiator to be cooled.

Therefore coolant boils at any hot spots inside the block until it cools down below boiling temperature.

This condition is made worse by folks running engines with retarded spark timing and the GAV closed. Normal GAV setting is at 1/4 turn open (richer).

Some folks lean out the mixture trying to squeeze out that last Mile per gallon increase.

[freak]

Originally Posted by Y-Blockhead

Is that after you shut it off or when it is running? The temperature will increase some when it's not circulating, but that's HOT!!

That's a very accurate instant read thermometer stuck right in the top of the radiator after 10-15 miles, stopped but idling.

[Mike V. Florida]

Originally Posted by freak

Just went out for a drive. The radiator is not over/under filled but I hear/see an occasional "glug glug" after I shut down and look in the radiator.

These can cause overheating,

1) The timing could be off or your not setting the timing lever for optimum when driving.

2) The carb is running lean.

3) Your radiator is not working at it's best.

4) Improper mix of antifreeze/coolant.

[1crosscut]

Yep that is much too hot.

Make sure your timing is set correctly. Very common cause of over heating.
Check to make sure the fan belt is actually turning the water pump.
Be sure that the fins on the radiator are straight to allow maximum air flow.
Check to see that the fins are attached to the tubes.
Make sure that there is not too much paint on the radiator fins.
If after checking that it may be time to pull the radiator out and clean it.
With the radiator out plug off the upper and lower pipes and put 1 gallon of full strength Simple Green and slosh it about several times per day for several days.
After that dump it out and I think you may be quite surprised by what comes out.

[BILL WILLIAMSON]

Backflushing at least once a year is a MUST! Rust flakes in the top of the tubes is the MOST common cause of overheating. Any amount of cleaning will NOT eliminate the flake problem! It's like there's a little FLAKE "factory"---hiding in the block.
Bill W.

[Ed in Maine]

Don't be so quick to put that meat thermometer in the top of the radiator after stopping the engine. It really surprises me sometimes how dumb I can be but I quickly turned the radiator cap and it sprayed all over my T shirt. I looked like a cooked lobster! Ed

[tbirdtbird]

that would be unusual for a non-pressurized system such as the A

[freak]

Originally Posted by Ed in Maine

Don't be so quick to put that meat thermometer in the top of the radiator after stopping the engine. It really surprises me sometimes how dumb I can be but I quickly turned the radiator cap and it sprayed all over my T shirt. I looked like a cooked lobster! Ed

The engine wasn't stopped it was idling. My dad taught me long ago about taking the cap off of a hot radiator. Been very careful about it since.

[freak]

Thanks everyone for all your tips. Today I checked the thermostat and it opens around 175F. Next I decided to flush the radiator with phosphoric acid. First I looking inside with a endoscope type camera and it looked pretty good. Couldn't really see any clogging. Flushed it anyway. Nothing really came out and the acid didn't change color much. When I rinsed the system I found that I could put the full output of the 3/4" garden hose in the top of the radiator and it runs right through. Next I checked my timing with a light. Last time I set it I set it to 25btc at full advance. Now it was running at 10btc full advance. Not sure why it changed. (I also have electronic ignition) Filled it with coolant and took it about 7-8 miles. Got back and it was running around 175F. I'm pretty sure it's fixed and I'm pretty sure it was because of the timing. I didn't really expect that or I would have checked it long ago. I'll know more on the next drive to work. Thanks again everyone!

[Bruce Adams]

Pick up a $25 Harbor Freight Infra Red Thermometer gun. Point it at the upper part of radiator in 3 locations and same towards the bottom. Record your readings and you will quickly see if you have any cool / clogged areas. It will, of course, also indicate the temperature of the engine & radiator.