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34 fordor owner 12-01-2025 07:29 PM

34 Ford Radiator Leak?
 

Hello, I have another forum going right now pertaining to updates on my 34 sedan that I’ve been slowly getting back on the road. I was sure the cooling system was going to be serviced at some points but it was going fine. Today after a short trip down the road and back I noticed there was water and cooler all over the bottom of the engine as it had blown from the radiator. Both bottom hoses are not leaking, no leaks from the top hoses and the radiator it self looks fine. In the picture the most water seems to be directly under the radiator. Sort of near the over flow hose. I also noticed some dirty water near the over flow hose. My theory is 2 options: 1) there’s is a radiator leak at the bottom tucked away where I can not see or 2) the water is not flowing correctly and coming back I it the over flow hose and emptying out the bottom in good amounts. No water seems to leak while at idle I’ve only noticed this after a drive down the road hitting about 30. Any idea or has anyone experienced something like this. Next time I have a free moment to work on it I plan to drain the radiator and flush it and check more leaks. https://uploads.tapatalk-cdn.com/202...6dfffbec20.jpghttps://uploads.tapatalk-cdn.com/202...cbc1d3282e.jpg

https://uploads.tapatalk-cdn.com/202...5c13226475.jpg

koates 12-01-2025 07:46 PM

Re: 34 Ford Radiator Leak?
 

Its possible you are overfilling the radiator. Only needs to be an inch above the top of the tubes or to the hole in the baffle and no more when cold. If you fill it right up it will only spit it out the overflow especially when you stop after a run. I know because I have two 34 Fords. Regards, Kevin.

Lawrie 12-01-2025 07:58 PM

Re: 34 Ford Radiator Leak?
 

Put a short length of clear hose on the overflow pipe and leed it away where you can see it,
then you should know wether its from there or somewhere else.

Lawrie

34 fordor owner 12-01-2025 08:15 PM

Re: 34 Ford Radiator Leak?
 

Quote:

Originally Posted by Lawrie (Post 2425597)
Put a short length of clear hose on the overflow pipe and leed it away where you can see it,
then you should know wether its from there or somewhere else.

Lawrie


Very good idea I will try this! For the water pumps, I want to get them rebuilt by skip but until then as long as they are not weeping or squealing they should be working correctly right? Thanks!

Drbrown 12-02-2025 10:36 AM

Re: 34 Ford Radiator Leak?
 

Don't know if your system uses a pressure radiator cap - my '47 uses a 4 lb cap. If pressurized obviously that would encourage leaking. Otherwise .... Agree regarding coolant level in radiator - personally I keep it 2 inches below top of neck. It may happen that water pump shafts start dripping if its seal wears out - might show after having just run the engine. Option: pull radiator and have a shop pressure test it.

Als48 12-02-2025 10:57 AM

Re: 34 Ford Radiator Leak?
 

What is your temperature running? I'm wondering if you might have a stuck thermostat or a blockage on one side of your engine.

AH

34 fordor owner 12-02-2025 11:37 AM

34 Ford Radiator Leak?
 

Quote:

Originally Posted by Drbrown (Post 2425684)
Don't know if your system uses a pressure radiator cap - my '47 uses a 4 lb cap. If pressurized obviously that would encourage leaking. Otherwise .... Agree regarding coolant level in radiator - personally I keep it 2 inches below top of neck. It may happen that water pump shafts start dripping if its seal wears out - might show after having just run the engine. Option: pull radiator and have a shop pressure test it.


I have thought about going ahead pulling the radiator getting it tested and re cored if I can find someone near me to do the job. As for the cap it has the same cap that it’s been using for its life I’m figuring, it goes with the car. One of the silver ones that match right into the 34 silver detail on the front of the car. As for a blockage, 3 yeses ago when it ran last I replaced all the hoses and flushed the engine and radiator but then it never ran as much as it does now not enough to really get it going. It’s possible that now it’s been road driven some things have been stirred up and may need another flushing? I will be over there later this week to troubleshoot further and test ideas.

Lawrie 12-02-2025 02:57 PM

Re: 34 Ford Radiator Leak?
 

It is fairly easy to take the top tank off, then clean out the tubes .
Lawrie

Ggmac 12-02-2025 05:28 PM

Re: 34 Ford Radiator Leak?
 

Is your fan belt adjusted correctly. It can cause pump bearing issues if too tight .

34 fordor owner 12-02-2025 09:46 PM

Re: 34 Ford Radiator Leak?
 

Quote:

Originally Posted by Lawrie (Post 2425719)
It is fairly easy to take the top tank off, then clean out the tubes .
Lawrie


On a ‘34 radiator am I able to take just the top tank off? How do I do this?

deuce_roadster 12-02-2025 10:08 PM

Re: 34 Ford Radiator Leak?
 

Taking either top or bottom tank off involves unsoldering it, best done in a radiator shop.

If you take the fan belt off and look into the radiator (with water visible) and run it, if you are seeing bubbles, it indicates a blown head gasket or crack.

34 fordor owner 12-04-2025 07:02 PM

34 Ford Radiator Leak?
 

Had a little bit of time to go and mess around on the car for a few…I’ve just been super busy. I made sure the water was good and got it started up, ever since it been cold and I’ve been driving it only takes about 2 turns and it fires up. We have some winter weather coming through the night so I wasn’t able to take it on road speeds just around the block (the main roads have been salted didn’t wanna drive in that!) with that drive it didn’t seem to leak any water, it’s definitely coming out the overflow. When I started it it was below the bottom hole after the drive it had risen. Also from what I could tell the water was moving while the was just running alone so the pumps should be working. So why does so much water come up and out the overflow at higher speeds? https://uploads.tapatalk-cdn.com/202...991d7ffe4d.jpg

The Art Doctor 12-05-2025 08:51 AM

Re: 34 Ford Radiator Leak?
 

Water expands about 3% when heated to around 180*F. This is why in old cars "it will find its own level". If you just leave it alone the excess will push out and what remains is 3% less than over full. If you keep filling it up it will keep pushing that 3% out. New cars do this too, that is what the recovery tank is for. In a closed pressurized system when it cools it creates a vacuum that sucks the coolant from the recovery tank back into the radiator.

34 fordor owner 12-05-2025 09:17 AM

Re: 34 Ford Radiator Leak?
 

Quote:

Originally Posted by The Art Doctor (Post 2426136)
Water expands about 3% when heated to around 180*F. This is why in old cars "it will find its own level". If you just leave it alone the excess will push out and what remains is 3% less than over full. If you keep filling it up it will keep pushing that 3% out. New cars do this too, that is what the recovery tank is for. In a closed pressurized system when it cools it creates a vacuum that sucks the coolant from the recovery tank back into the radiator.


Oooh I see so next time it spills out I’ll leave it be and not fill it up any more as long it’s not overheating then I’ll have to come back to the issue then. Got it!

KiWinUS 12-05-2025 09:22 AM

Re: 34 Ford Radiator Leak?
 

Quote:

Originally Posted by 34 fordor owner (Post 2426142)
Oooh I see so next time it spills out I’ll leave it be and not fill it up any more as long it’s not overheating then I’ll have to come back to the issue then. Got it!

Or you could put a hose on over flow and then place the other end of hose in a container ( I use a soda bottle on my 36) that is stashed somewhere inconspicuous.

The Art Doctor 12-05-2025 09:36 AM

Re: 34 Ford Radiator Leak?
 

Quote:

Originally Posted by 34 fordor owner (Post 2426142)
Oooh I see so next time it spills out I’ll leave it be and not fill it up any more as long it’s not overheating then I’ll have to come back to the issue then. Got it!


Yes, just leave it alone. Note where it stabilizes at and once a year check it, it may need a slight top off due to evaporation from the open (non-pressurized) system. If it is a bit low just fill it back up to the lower level and go on and not worry about it for another year. I check mine before winter to test its resistance to freezing with one of those testers with the colored floating balls as a few of mine are parked outside year round (too many cars and only two garage stalls) and it does get super cold here in Atlanta a few days/weeks a year.

34 fordor owner 12-07-2025 10:13 AM

Re: 34 Ford Radiator Leak?
 

Sounds good!! In a previous forum I asked about the grease I should use in then mechanical water pump fitting. I was a told just to use the cheapest and lowest temp stuff, but from reading other forums I also see that the grease can get into the water so it needs to be water proof, is that right? I’m thinking on using stalube marine grease from harbor freight would that work well?

The Art Doctor 12-07-2025 11:14 AM

Re: 34 Ford Radiator Leak?
 

I'd use the grease for boat trailer wheel bearings, it is engineered to keep water out. I have yet to do mine, but its on my list. Most people tend to use excessive grease being used to ball joints where one wants to see it squeeze out to make sure they get enough in. But on these, if it has a zerk fitting like mine, just a single pump is sometimes too much. I believe the original style has a cap that has to be removed to reveal a nipple through which you pump the grease. Paul Shinn on youtube (He's on here in the Model A section ) has a series of lubrication videos for Model A's I'd recommend having a look at as the 32-34 share many traits with Model A's. He has covered A water pump lube in at least one video even though he personally uses sealed bearings that do not require lube. The A water pump is totally different in design but the thinking is the same, using one or less pumps only to keep grease out of the radiator.

34 fordor owner 12-07-2025 02:25 PM

34 Ford Radiator Leak?
 

Quote:

Originally Posted by The Art Doctor (Post 2426459)
I'd use the grease for boat trailer wheel bearings, it is engineered to keep water out. I have yet to do mine, but its on my list. Most people tend to use excessive grease being used to ball joints where one wants to see it squeeze out to make sure they get enough in. But on these, if it has a zerk fitting like mine, just a single pump is sometimes too much. I believe the original style has a cap that has to be removed to reveal a nipple through which you pump the grease. Paul Shinn on youtube (He's on here in the Model A section ) has a series of lubrication videos for Model A's I'd recommend having a look at as the 32-34 share many traits with Model A's. He has covered A water pump lube in at least one video even though he personally uses sealed bearings that do not require lube. The A water pump is totally different in design but the thinking is the same, using one or less pumps only to keep grease out of the radiator.


The marine grease says it is applicable to boat trailers so that should be a good option for me. I’ll look Paul up and give him a watch. Thank you!

koates 12-07-2025 06:42 PM

Re: 34 Ford Radiator Leak?
 

Forget about marine grease because it may not have a low enough melting point. Specific water pump grease has a lower melting point (75 deg c) than your engine coolant so that it melts to a liquid form if it gets past your water pump bushings and into the coolant. If it does not melt and stays in lumps it will block your radiator tubes and cause overheating. I believe PENRITE make a specific water pump grease for old cars, or go to a tractor supply outlet. Regards, Kevin.


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