Pressurized radiator, good or bad?

Electrocutioner

Electrocutioner

Junior Member
I am a new model A owner and have issues with overheating/water pushing out the overflow. Can anyone give some input on the benefits of a pressurized system?
 
The water needs to be just above or at the top of the core, more and it will push it out. If you're overheating your radiator may be plugged. Are you running a t/stat. Timing set correctly??
Need more info on what you have, what you've done, etc.
Also, try doing a "search" for overheating.
Others will probably chime in.
 
Welcome to Fordbarn! You likely have both a block and radiator that need to be thoroughly descaled/ derusted/ boiled out with cleaner. A pressurized system will not fix that. Don't be in a hurry to make changes.
 
Is it actually overheating or are you assuming it's overheating because it's
losing water out the overflow.

Bob
 
I agree with all the above, FYI if its in its stock form and truley overheating "modernizing" the system isnt going to fix it.
 
I'm only two years into the A and have learned a full radiator will spit out fluid until it reaches it's comfort level which appears to be just under the baffle in the radiator. I rock the car and with a light can see fluid around the overflow tube. That is where she likes it.

Someone here posted once to fill it right up and then let it spit it out and make a mess. Then refill it right up but measure what it took (let's say it took a quart and a half...in my case). Do it all over again. If it always takes the same amount then that is the level to leave out...simple. They don't get filled to the top!

Overheating on a Model does not have the same symptoms of a newer pressurized car. My A spits out the cap and the overflow when too full. I know not to fill er'up but if I' m going like 50 miles I tend to. Get a Motor Meter...not like a modern temp. gauge but a real indicator.
 
Last edited:
Water pushing out the overflow is not necessarily a cooling system problem. As the water heats it expands, and if full up will overflow even if everything else is fine. This is not unusual with new A owners. The A's have lots of quirks.
Just try running it after the overflow and see what the level is. If you can just barely see the water, that is fine. It need not be topped off. If this does not work, or you are truly overheating, per post 4, then you are into cleaning.

JG61 beat me and explains it better. Good luck.
 
Keep the water just over the tubes of the radiator. Keep on eye on it as you don't have the reserve capacity as you do with a modern car with a reserve tank.
 
'A "negative" is that the water pump will be more likely to leak with a pressurized system'

along with everything else

I have a fully cleaned block done with lye and a re-cored radiator, run no thermostat, and have to use cardboard in front of my radiator in the middle of Texas summer to get my temps up to 160-180. I use an electric gauge. I don't like thermostats because they restrict the water flow to cyl #4
 
Fill the radiator and with the cap off crank the engine over. If Old Faithful appears you have got a head gasket problem.
 
The purpose of a pressurized system is to raise the boiling point of the water. If your car truly needs the boiling point raised, you have an engine problem that will only be disguised buy the new radiator. A stock Model a engine will run something like 170 180 tops. Even in South Florida parades in July we don't have boil over problems.

What are you doing with the spark rod once you have started the engine and go driving. Have you checked the timing and exhaust for blockage?
 
Take some time and search past threads on the subject. There are numerous threads. The common cause is the over filling of the radiator. Wayne
 
Ok, update. It was pushing water out like crazy. With a little help I corrected the carburetor and timing adjustments and no more water loss. I think the radiator is going to stay as it is. Thanks for all of the help!
 
A stock radiator does just fine. I had mine pressurized for touring in the mountains where water boils at a lower temp. And it's nice to never have to add water in the Texas heat. Just sucks it back in from the overflow as needed.
 
Denny Specker sold a few 3.5 psi caps for cars that weren't overheating, just throwing the water out. That and a hand cut rubber gasket under the cap cured a lot of troubles at bery little cost. I met a guy in Barstow that was canceling his Tx trip because he couldn't keep water in his radiator. We put the 2,5 pound cap setup on and he never added water the rest of the trip. That might be a solution. He's in the roster, I'm sure. Give it a try unless you are overheating with a full radiator, only if it is being thrown out the overflow, that;s where he put the new cap, in the overflow line, then semi sealed the system. 801 282 8005 is his phone. (in 2008)
 
If you have a need to keep your radiator completely full, just use a stock cap, make sure it has a good seal, then push a hose on the overflow and run to a recovery tank under the hood.
 
If you drive your car at speeds like most Model A owners do, you will find a stock system will serve you well if properly maintained.

Like Jordan, I have a counterweighted engine. I don't know Jordan's driving habits but I often spin mine pretty fast. I have a pressurized system with a leak-less pump installed about 85,000 miles ago and find it works well for me. I replaced the leak-less pump about 15,000 miles ago. (About 70,000 miles on the original leak-less...pretty amazing!)

A couple years ago, with the pressurized system, I completed a 9200 mile trip and needed to add water only once. This past summer I completed a 3500 mile road trip with mountain driving plus the driving since and have not added a drop all summer.
During these trips, I often push the engine hard. Before the pressurized system, I often needed to add water to maintain cooling.

Severely overheating an engine can cause catastrophic failure, I have seen it many times while rebuilding engines.
Due to my driving habits, I invested in a pressurized system to avoid damage to my engine.
Good Day!
 
Last edited:
You must log in or register to reply here.
Back
Top