Cooling Problems, where to go next?
 

Alright guys I really need some help.

Fall 2017 I picked up a 1936 Model 51 with what I've identified as a 1937 flatty (pumps as motor mounts). I did some initial repairs, one of which was replacing the passenger side upper radiator hose as the one that was installed was kinked at the base. I have been driving the truck all winter with no major problems. Around march I took it out for a drive and after I noticed what I originally though was oil/coolant foam dripping from the overflow. After a mild heart attack I determined that it was just coolant foam, NO oil. It was brown color from rust, not oil. I read the forums and determined a few potential causes: cracked block, air ingestion at water pumps, head gasket. I set out to eliminate possibilities.

Compression test: 98-100 all cylinders
tested for exaust gas in coolant test after driving with block checking fluid: negative
Vinegar radiator flush: complete, no change
Running straight water: less foam but still over heats on days over 50 deg.

Situation the other day:
I got up and took the truck to work (530am, 50 deg) truck hit 190 in a 30 min drive. A caring motorist stopped to tell me I was leaking fluid from the driverside (overflow) while driving. The way home (2pm, 80 deg) truck hit 190-200 in 15 min, I stopped to top off the radiator and let the truck cool for 15-20 min. Restarted my journey home made it another 10 min before the truck overheated, boiled over and I stopped at 210 on the gauge.

Side note I discovered a small crack in the water jacket on the passenger side. It weeps water, but the cooling issue is the priority right now.

Today I decided to pull the lower hoses and see if there was any sediment, I found one side partially collapsed, but no sediment. Just for haha's I pulled the driverside upper hose and found a thermostat jammed in there sideways.

If you asked me Yesterday I would have said flatheads didn't use thermostats, after a quick google search and a few ford barn posts I have been educated.

What's next? What to test, what to try?

Re: Cooling Problems, where to go next?
 

when you flushed with vinegar-how muddy was the water coming out? is the water flowing in the top tank when the rad cap is removed? remove hoses and back flush the engine from the top hose connection. check radiator for plugged core--back flush it from the bottom up. plug up with a rag or something like that one side at a time to flush each side of the core. do you have access to a heat gun? you can use that to spot a plugged radiator-plugged -tubes will be cooler than the rest. give these a try and report back

Re: Cooling Problems, where to go next?
 

Some of the causes for overheating: Clogged radiator, large pockets of sediment in the block(especially in the rear), bad water pumps(rarely), retarded ignition timing, lean carburetion. There's more , but these seem to be the most common.

Re: Cooling Problems, where to go next?
 

Your "cracks in the water jacket"........ what is that about?

Hopefully you have impellers on the water pumps, even in
perfect condition they have a pretty tough job since they
don't have a plate behind the impeller.
Is the water level truly "full?" My truck takes awhile for the
water level to stabilize.... sometimes a week worth of driving.
What's the radiator condition?

Re: Cooling Problems, where to go next?
 

If it was mine.....I’d do a complete clean out of the cooling system. Pull the radiator and test the flow....pull the water pumps and clean out as much as I could. Leave the thermostats out for now till I got the overheating problem resolved. When this was done, I’d check timing, carb and make sure I had an accurate temperature gauge when I test run it this first time out. You really don’t want it to boil over anymore.......Mark

Re: Cooling Problems, where to go next?
 

When I did the vinegar flush it wasn't too dirty, but I also may have errored; after flushing I only drained using the block drain cock. It was pretty rusty / dirty when I pulled the lower hoses yesterday.

There was some water flow with the cap removed, I have nothing to compare it too when I get it up and running again I will try to shoot some video.

How do I check the timing?

I'm not really too sure on the block crack, its on the pass side originating at the drain cock and going towards the firewall maybe 2.5 to 3 inches. The truck has leaked water since day one, however I could see it dripping from the water pump shafts. We're talking a 8" circle of liquid if left for 2-3 days. It could have been leaking from the pumps and the crack and I just never saw it. Or, it was filled with sediment or block seal of some kind (if the old owner knew and didnt' tell me), perhaps the vinegar flush opened it back up.

Any tricks to lifting the motor to do the water pumps?


Things I'm going to try / do:

1. Borescope the water pumps in place to inspect the impellers.
2. Flush the block & radiator / check flow
3. Get new (non collapased) radiator hoses and install
4. Test w/o t-stat
5. Thermal camera radiator, look for plugged areas and report back.

Re: Cooling Problems, where to go next?
 

It's not so much to check timing as it is to thoroughly inspect the distributor for condition of the points, condition of the advance mechanism, and check of the internal timing of the unit according to the service instructions for the helmet type distributor.


A coolant leak anywhere in the system is a problem. I add caution to folks that used mild acid to clean the cooling system. It can remove crud that had been sealing the old system up. The other thing a lot of folks don't do is to neutralize the acidic action going on in the water jackets & radiator after performing this process.


The modification of pumps by Skip and addition of his 4 psi overflow valve can also be a help as long as the system is well sealed and there is no obstruction in the radiator & other system passages. Many of these old motors had left over core sand and wire in the water jackets after the casting process. Some are worse than others. Ford did a fair job of shaking it out but the wire generally stays there till is rusts to nothing.

Re: Cooling Problems, where to go next?
 

The vinegar ate the rust sealing the crack

when it is drained look in the radiator cap--see how many tubes are clogged----my 36 the radiator "passed" a flow test, but with the tank off 50% of the tubes were clogged

Re: Cooling Problems, where to go next?
 

Plus 2 with Kurt , A flathead will cool in the winter but summer will bring out the weakness , Also some trucks had a six blade fan so increase air flow ,and as said check vacuum pipe on the distributor ,Ted

Re: Cooling Problems, where to go next?
 

If the coolant is foaming below the boiling point, your problem is probably caused by air being sucked in to the cooling system around the water pump shafts. Your overheating starts as the foaming coolant is pushed out the overflow and you don't have enough coolant in the system. There are many on this sight that do not believe that this can happen. I learned first hand. Fought the foaming coolant problem all one summer on my 8BA. Local flathead expert put me on to the cause of my problems. Rebuilt the water pumps, problem solved. If you want more info on the subject, e mail me at [email protected]

Re: Cooling Problems, where to go next?
 

I look forward to hearing the results and planned solutions to your tests.... Mark

Re: Cooling Problems, where to go next?
 

Report back if you find a solution.
Short ride with mine today got it up to 150* with no t-stats.

Re: Cooling Problems, where to go next?
 

I just pulled the radiator from a 35 Tudor last night. Overheated on a short drive. Some of the tubes, that I can see, are plugged. Going to have the radiator rodded out and will flush the block with a mild soap.

Re: Cooling Problems, where to go next?
 

I'll tell this story - just in case it helps anyone at all.

I had a 57 Buick. I got it running from a non running condition (transmission rebuild). The first long journey I went on, after about 50 miles, it started overheating. I had to abandon plans to go to the show we were en route to, and try and get home. We were able to get home by stopping at every service area and hosing the radiator down with cold water.

Now when you hose it down, what you will notice is that some areas of the radiator dry off quite quickly. Others stay wet longer and some stay wet and never dry. You will observe vertical stripes of wet and dry patches.

The dry stripes coincide with the parts of the radiator that are not blocked. The wet parts show where it is blocked and not transferring any heat into the external water.

I removed the bottom tank and rodded out the tubes. Once back together it behaved perfectly.

So if you think you have a partially blocked rad, try hosing it down and see if it gives you any clues.

Mart.

Re: Cooling Problems, where to go next?
 

Mart,

Those are good observations. Thanks for sharing.

Re: Cooling Problems, where to go next?
 

Yes good observations

Re: Cooling Problems, where to go next?
 

A modern infrared temp gun might also be of use there. Some fancy outfits even have the infrared scanner where you can look at it for cold spots but I'm not that rich yet. More than one way to skin the cat now days.

Re: Cooling Problems, where to go next?
 

There is an Infra-Red Photo App for your smart phone and it is free.

Re: Cooling Problems, where to go next?
 

Great info Mart. Thanks!

Re: Cooling Problems, where to go next?
 

When I did the vinegar flush it wasn't too dirty, but I also may have errored; after flushing I only drained using the block drain cock. It was pretty rusty / dirty when I pulled the lower hoses yesterday.

There was some water flow with the cap removed, I have nothing to compare it too when I get it up and running again I will try to shoot some video.

I will flush the block and radiator prior to reinstalling the hoses.

How do I check the timing?