overheating.. looking for suggestions

[kevinshea]

Took my 35 with 59ab engine out of storage, got it all set up, test drove it and did a bit more work on it. Then it sat for 10 days.. Got it back out on the highway at 55 and within about 2-3 miles coolant was blowing all over the place.. exited... added about a quart... got back on the highway and it started to stumble and couldn't get over 30, lugging hard... pulled off again and towed back to a vintage car shop...

Now in the garage, the car will overheat within 10 minutes at idle. Pyrometer shows radiator temps at even, no hot or cold spots.. replaced carb with another rebuilt.. got strong fuel flow from electric pump.. Each water pump is turning and moving coolant... no "obvious" noxic smells at Radiator cap, nor any oil slicks, nothing odd from the exhaust.

Next testing will be compression and internals checks...

Any suggestions?

[hueyhoolihan]

i would be suspecting that coolant flow is non-existent. thermostats stuck closed? i would be double checking what was in the radiator too.

[rockfla]

Are you running thermostats?? Possible issue with one maybe getting turned sideways and allowing the water to flow through to fast or maybe one is stuck or partially stuck and not allowing enough flow??

[petehoovie]

Did the coolant foam?...Suspect a leaking head gasket...Do a "sniff' test for exhaust gases in the coolant with a coolant exhaust gas test kit...

[kevinshea]

So far... I was running without thermostats... and there was no foam in the coolant, at least none that I saw.. and If there was foam I would have expected to see some lingering elsewhere, as the coolant sprayed itself everywhere...

Been trying to run ThermoCure agent but I need to wait until I get the overheating under control. No sense blowing that stuff all over the under hood.

[rockfla]

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You know what they say about "opinions"


ME, in my opinion, running NO thermostats is never a good idea.....They are installed (originally) for a reason, no matter the climate. AGAIN...JMO coolant has to flow at a certain "rate" to slow or in this "possible" case to fast and things don't cool like its supposed to, the engine never gets to proper operating temperature to burn the fuel properly....Nothing good happens ALL around!!!

[ford38v8]

Originally Posted by rockfla

You know what they say about "opinions"


ME, in my opinion, running NO thermostats is never a good idea.....They are installed (originally) for a reason, no matter the climate. AGAIN...JMO coolant has to flow at a certain "rate" to slow or in this "possible" case to fast and things don't cool like its supposed to, the engine never gets to proper operating temperature....Nothing good happens ALL around!!!

Speaking of opinions, I have a couple about your advice. Yes, there is a good reason for thermostats, and only one reason for no thermostats: On a race car, the restriction costs horsepower.

Coolant moving too slow, again, I agree. Once an engine reaches operating temperature, open up those thermostats.

Too fast? I do not agree. That is an old disproven theory that attempts to explain another racing trick to save horsepower: Remove every other vane in a water pump. An exception to the too fast theory is when it causes cavitation.

Finally, about a flathead never getting up to operating temperature. Really? That doesn't happen except on a very cold day, or while descending from a mountain. the harm that will do is extend the warming-up period longer than it need be, which isn't good for any engine.

[Ggmac]

Agree with the disproven ‘ too fast idea ‘ . Are you overfilling your radiator? You should just fill it enough to cover the tubes when looking in it . If you fill it completely, it’ll puke all over when it expands and can’t go anywhere.
Have you changed you radiator cap ? Pretty sure it isn’t pressurized, wrong cap may cause water pressure to do harm to weak or near failing gaskets .
These wont fix any running issues but the heat can certainly take its toll on coils, condensers and such . Good luck

[kevinshea]

Few more adders...

I've had the car running for 23 years without stats and it always ran well..
yup, Only fill to the top of the fins
Have purchased 180s and will add in to see if any different.
Changed out the radiator cap gasket.
Way back when, I added a 2-3lb pressure valve on the overflow line and fed that into a "puke" tank behind the baffle plate. I can remove as appropriate and let it run at atmosphere.

[69a]

Just a couple of suggestions. Not enough flow through radiator, some tubes are blocked, causing a restriction.
Or broken spring on one set of points, causing ignition timing to be too far advanced.

[Flathead Fever]

I would start with an infrared thermometer gun and measure the outside temperatures of the engine's coolant inlets and outlets on the radiator. Then check the temperature of the radiator's core in different spots. Maybe even the exhaust manifold ports temperatures. At work most of the time overheating was a radiator or thermostat but, on an engine, as old as a flathead it can be all kinds of different stuff. You can take a block pressure test, put some pressure to the radiator with a leak tester, not too much pressure or you might blow up a soldered joint on the radiator. Let it sit for a long time and see if the coolant system holds pressure, if it doesn't hold then pull the plugs and see if any water squirts out of a cylinder. Usually, the leaking cylinders spark plug will be washed shiny clean, no carbon like the others plugs would have. Head gaskets eventually fail and yours are over 20-years old. One reason is some people refuge to use coolant in their engines but it's not there for only cooling it prevents the gaskets from rusting away. Really important to run a 50/50 mix of coolant.

[chap52]

Don't fill the radiator to the top. Just cover the coils. When we overfill them they will "spew" out the extra and seek their happy level.
Also I always drilled a couple of small holes in the thermostats when I installed them. Seemed to help on start-up as engine warmed up.
"Enjoy the adventure..." Chap

[kevinshea]

It appears that the issue was charging and a weakening voltage. Seems that as the voltage (recharge in the battery) the feed to the coil and the resulting spark went from "working" to "poor" to crappy... it seems to run fine now, but unable to road test given the rain we are having. Why would this result in the overheating?

[hueyhoolihan]

AFAIK stock flatheads didn't have pressurized cooling systems. when overheating the coolant was designed to overflow through a hole in the filler just below the top and then through a hose to the ground. only if a hose blew out, would a large amount of coolant be thrown into the engine bay.

BTW. it's possible to inadvertently turn a non-pressurized system into a pressurized one, often with dramatic results, by installing the wrong radiator cap. it happens when the chosen cap blocks coolant flow from BELOW the overflow entrance point in the filler neck, and so prevents hot/boiling coolant its escape path. usually it's accompanied by a blown hose or hose connection. these caps often have a levered relief valve built into the top of the cap.

you are right, IMO, to be skeptical of finding the cause of your overheating as, the symptoms having little to do with one another. alas, you may have simply found another problem. good luck.

[pistonbroke]

I have cured more high temp/over heating engines with a proper tune up then any other fix.Timing , week or irradic spark or poor fuel are all very common cause for hot running engines. The ford V8 needs these to be all set propperly as possible do to its exaust running through the block dissapating heat as it goes. Tim

[Mart]

I had a French motor in a 46 coupe. That would overheat after a longer drive. The vacuum advance wasn't working, so as that was the only advance available, it had no advance. Running effectively retarded caused it to overheat. So yes, a good tuneup will help. The only other overheating issues I have had were due to a stuck closed thermostat. It was on the side that had no temp gauge, which didn't help.