Why Do They Overheat?

[Shadetree]

Most flathead V-8 Ford engines seem to have a common problem with overheating and we blame the design. Yet some Fordbarner's have no overheating issues. There has to be a reason that some do, some don't. In the 50's I owned several flathead Fords with no heating problems whatsoever. We didn't have high volume pumps, Purple Ice, thermostats or pressure caps. Something has happened over the years to create this problem. We can't put the blame totally on age. I have owned other antique cars that never once overheated under any conditions, parades, idling for long periods or whatever, they ran cool. If our Fords were this touchy when new, they wouldn’t have sold so many of them. There has to be a common denominator, what is it?

Shadetree

[John Kennedy]

Ya know, I've had the same thoughts before, and really just attribute it to several small factors that add up to one result (overheating) :

More traffic - slower speeds
More time passes - more corrosion in an older built engine
Cheaper gaskets - lower quality
More accurate gauges - some minor overheating went unnoticed before
Gas quality - more alcohol in tank, less in driver
Maybe they were this touchy when new.


I'm sure there's more

[rotorwrench]

Folks used to wear sport coats and ties in the summer back then too with no air conditioning. In the more southern states, it was warmer than the more northerly states so they had more problems with cooling system performance back then. The US climate is not a lot warmer than it was back then but it is warmer. When I was a kid on a Kansas farm, it would get pretty hot in the summer months and you would notice a rise in temperature when a car would sit and idle for long periods. They would get pretty close to the red line but would only cross it when there was a problem. Cracked valve pockets, leaky water pumps, leaks in the radiator or heater hoses, and sticky thermostats all contributed to overtemp just as they do today.

I really haven't noticed any change in performance of cooling systems even on more modern cars. Crappy thermostats and poor quality ignition systems components all contribute to more modern overtemp problems.

[Steves46]

Although I wasn’t driving anything other than my Mom and Dad crazy in the 60’s to mid-70's, I absolutely agree with John’s comments; especially the “more traffic and slower speeds.” Whenever I take the 46 for a cruise, crawling through traffic and stopping at every $%^& * traffic light that are only ¼ mile or less apart, it certainly taxes the temp gauge. Once I can get passed that stovepipe, the temps go back down to normal. With lack of continuous airflow, perhaps the Flathead always had the tendency to overheat but then again back in the day, I suspect there wasn’t as many cars and stoplights slowing you down.

[Vic Piano]

I can remember, as a kid in the '50's, driving with my dad in his '49 Merc Convertible in Atlanta, GA stop and go traffic and though the Merc had other issues, overheating was not one of them. I've owned a few Flatheads over the last 45 years and I only had one that had a propensity of running hot and overheating. I think that part of the problem can be attributed to build up of an assortment of crud in the water passages (I have cleaned several blocks that had (casting sand?) in them along with a lot of rust. I've read (don't know if it is true or not) that Ford developed the iron compound to promote a film of rust in the water passages to aid in cooling. I think the best thing you can do to insure that your Flathead(s) don’t overheat is to make sure that all the components of the cooling system are up to par, that includes the radiator, fan, water pumps, water passages in the block, ignition timing, fuel/air mixture, exhaust manifolds/headers gaskets, etc., etc. Just my opinion but it works for me. Vic

[dude]

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All engines will overheat if your cooling system isn't working 100%, I've removed a lot of cord rods from ol'flatheads,(Henry did a pood job removing them all) What Vic says is correct,make sure all components are up to par..

[Shadetree]

Thanks John.

More traffic - slower speeds- You are right, we only had one red light in my hometown. But there were Fords in big cities back then too with heavy traffic.

More time passes - more corrosion in an older built engine
Cheaper gaskets - lower quality. No doubt.

More accurate gauges - some minor overheating went unnoticed before. Using the original thermometer type guage. I used a meat thermometer at one point to check the gauge.

Gas quality - more alcohol in tank, less in driver. I use only non-ethanol gasoline in my old cars, or so advertised.

Maybe they were this touchy when new.

I still think there is a difference in some of the Ford engines. They run cool under the same conditions as the others run hot. There has to be a reason. I wish I knew what it was...



Shadetree

[blown49]

I believe many times it is caused by bad timing. Points today are not the quality of old and the fibre shoe that rides on the dizzy cam wears more quickly than te older ones. This causes the points to close up retarding the timing creating the overheat problems. On my Merc when the gsuge starts running higher I pull the cap and reset the gap. 9 times out of 10 the points have closed up.

Jim

[flatjack9]

I agree totally with Blown49. The other thing is that the advance mechanism gets gummed up on the early distributors and the vacuum can goes to pot on the later ones. Again retarded timing is the result as well as over heating.

[~~Walts37~~]

Guess I am one of the lucky ones with (no) heating problems on my 59 ab. I did have my radiator totally rebuilt & the engine re-builder wanted to put sleeves in all cylinders to help prevent overheating. I told him to do what ever he thought should be done. I have original thermostats with Mac's water-pumps no pressure system use regular antifreeze & leave water at about 3 inches above the top baffle in the radiator. I have not had this engine overheat in any kind of weather or driving. I do not know why just lucky I guess. ~~Walts37~~

[Chris Nelson]

I have a 59AB and an 8RT. Neither of them overheat. They can sit at idle for extended periods with no temp rise other than what the thermostats are set at. I think the answer is that my engine builder took pains to clean out the block passages with a sharp pointed rod. He dug out over a quart of old foundry sand and crud from the back of the block. It seems that the junk migrates to the back of the block over time. Henry was not doing a good job of having the foundry sand removed. They would run the block over a vibrating table, but I don't think anyone looked to see if all the sand came out. My blocks are clean as a whistle and as a result they run right at the thermostat temp.

[Fairlane500]

A clean and crack free block, clean heads and radiator, good water pumps and correct ignition timing they run just fine. Any one of the above elements seems to get them to overheat.

[richard crow]

vick i know you are from long island ny. have you ever been on the southern state pky on a sunday night going west when they had the toll boths .every make of car ever made was on the side of the road with there hoods up. i drove home to brooklyn from the hamptons with a 51 merk & never got the car in third speed till i got to flathbush ave but it never overheated.but it wasen,t board 80 over no duel carbs no mickey mouse dist. no fancy alm heads no chevy. valves no 3/4 cam

[Rocketsled]

I just had my original 59 A/B's rad recored, and now it runs too cool.
Will have to put the thermostats, which were out for the flushing, back in.
The old core looked great, but the tubes were plugged with calcium deposits that the white vinegar treatment I tried couldn't dissolve. Maybe it's because the car was from Iowa. Also, the rad-man said the core was incomplete in the middle from some old repair job.
Now I'm looking forward to being able to use the old girl in the summer!

[Vic Piano]

Originally Posted by richard crow

vick i know you are from long island ny. have you ever been on the southern state pky on a sunday night going west when they had the toll boths .every make of car ever made was on the side of the road with there hoods up. i drove home to brooklyn from the hamptons with a 51 merk & never got the car in third speed till i got to flathbush ave but it never overheated.but it wasen,t board 80 over no duel carbs no mickey mouse dist. no fancy alm heads no chevy. valves no 3/4 cam

Richard, I know that route very well however, I lived on the North Shore and I drove the Seaford-Oyster Bay Expressway from Syosset to the Southern State Pkwy through Brooklyn, over the Verrazano bridge to the outer bridge crossing to exit 10 on the NJTP to get to my studio/office Monday - Friday for a year, in my '46 TuDor and sometimes in my '53 Sunliner, a hundred miles each way, and I never had any overheating problems in either however, I did lose a master cylinder in the '46 on the Cross Island Parkway once. Ah the good old days… Vic

[FlatheadTed]

I think most of the time its a Radiator issue ether blocked or not enough tubes,I don't think a lot of the cores you get today are suitable . Ford offered about 3 Radiators one of them was 4" thick for hot climates . On a recent Early Ford convention run recently about 4 Flathead over heated 3 34s one 39.3 dumped water out over the windscreens at the top of a steep incline ( this may have been lack of water and non sealing cap .I talked to a old Radiator guy he said a Flathead needs a Fin and tube not a honey comb like some were replaced with in the 60s ,When I took the top of mine it had about 12 less tubes than the stock Ford ones .you could see the remains of the old tubes .The old guy is now replaced one of the cores one of the 34s .I l will report back about the result .Not to detract from what Skip does but I have found that a catch bottle works quiet well as suggested from a previous FB poster .

[tiquer]

I recently disassembled the engine from my 53 merc pick-up and there was tons of rust coming out of the water jackets. A normal hot tank soak will not remove all of this so I took it too my favorite engine builder (Valley speed) and the technician said to use a new method called back and blast. He showed me some blocks that they did and they looked like a brand new casting they were that clean. For $135 I will not hesitate to do it.

[FlatheadTed]

Here.s a shot of my Radiator you can count the old tubes .On trucks Ford had 6 blade fans and shrouds fitted by Dealers if there were over heating problems , Cleaning the block is important after a rebuild we run some nee hi Hose /stockings fed into the top tank then folded back over the neck under the hose clip

[Bassman/NZ]

A common complaint I see here is the lack of airflow during parades, stoplights etc. Well I fail to see how that can be an issue when the flathead was used for so many standing engine situations, waterpumps, driving saw mills, fire tenders, generators etc, etc. They often ran for hours or days even, with no airflow other than provided by the fan. I think the OP is right, something is decidedly different, I just dont know what. I had close to a couple of dozen flatheads in the 60s and 70s, and I dont recall any of them giving trouble in the cooling dept.

[Coupe35]

I think even back the they had problems. That's why ford added the fins to the inner fender, change the radiator design several times thru 35/36, had the 6 blade fan for extra cooling, experiment with different water pump designs and eventually put the water pumps at the bottom of the engine for more flow. Like someone stated, there was not as many stop lights and the speed was not as high as today.