Overheating 312 T-bird

R

Royal Ryser

Well-known member
I need some help/advice. After setting a few years with only a few miles put on every year, my bird is heating pretty badly. I have run it with vinegar for a couple of weeks, then soda in the water and drained and flushed it twice. It heated badly with the thermostat in so I took the thermostat out.
Now when I drive it at 60mph it heats up to HOT in about 7-8 miles. By then it is blowing water out of the overflow tube like a geyser.
Any suggestions?
Thanks
 
You're overheating with no t stat, my guess would be a stopped up radiator, bad water pump or your block is plugged up. Have you ever had a problem with rust in the system?
 
do this simple test remove rad cap fill rad to about a 1/2" from the top. with the cap off have some one race eng to about 1.800 rpm. if level drops rad is not cloged if it throws water out the filler rad is cloged.
 
if engine heats on long high speed drives or pulling grades the radiator is plugged, or maybe the water pump is bad, to check it grab the fan blade with the belt loosened, try to move fan side ways and in and out, any movement in either direction replace the pump, but I still say its the radiator, there are no chemicals on the market or in a bottle that will unplug a radiator with plugged cores, the chemical has to flow passed a plug a little to desolve it, if its completely plugged the chemical wont do any thing but lay there on top and do nothing, it seems like you need to have the radiator rodded out, another check you can try is if you have an infrared heat gun, aim it at he top of the radiator, if its hot at the top and cold at the bottom there is no water circulation in the cores, you can do the test with your hand, but be careful, you will be able to feel the difference from top to bottom of radiator, if its to hot to hold your hand at the top of the cores and cold at the bottom very good chance of no circulation
 
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Next question would be what was in the system. Did it have any anti freeze, or plain water? Do you have a drain petcock on the pass side of the block, and does it drain freely. My bird doesn't have a spring in the lower hose, but on cars that do those sometimes collapse/corrode and impead flow. Yours is a more severe than normal problem, but I don't think there's any 'bird owners out there who haven't fought a heat problem.
 
Years ago I had an overheating problem with my ’57 Bird. I checked the timing, and it was right on. I replaced the thermostat. The radiator wasn’t that good so I just went ahead and replaced it with a larger one. The problem persisted. One day I was driving down the street and felt a slight pulsing in the power. It turned out that there was a busted diaphragm in the distributer and it was throwing the timing off and causing the overheating. It’s a long shot but something to keep in mind.

Charlie Stephens
 
temp gun or you hand does not lie, if the rad is hot at the top and cold at the bottom the rad is plugged
 
an easy thing to try is one of those prestone back flush kits. It worked for me years ago and now I'm a believer. just follow the directions on the package. I have used it several times on diff engines even ones that had fresh water and supposed to be drained clean. But until you shoot the water, forced in the other direction its difficult to get the crud and sediment out of the block and rad. it just settles. try it. can't hurt.
 
No luck, yet. Radiator is hot both at the top and bottom.
I'll have to try something else, maybe Saturday. I still have to check the timing. The hoses are new and unobstructed.
Thanks for all of the ideas.
Royal
 
Royal Ryser said:
No luck, yet. Radiator is hot both at the top and bottom.
I'll have to try something else, maybe Saturday. I still have to check the timing. The hoses are new and unobstructed.
Thanks for all of the ideas.
Royal
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If I remember correctly you remove the vacuum line from the distributer to check the timing. If the problem is with the diaphragm it won't show. Maybe you could look for fluctuations in the timing at a given RPM with the vacuum line attached. Be sure to post what you find as I am about to bring my mother's '57 Bird out of a 40 year slumber.

Charlie Stephens
 
Are you losing water out of the radiator? If you are, it could be the cap is faulty, thermostat stuck ( I see you have removed yours), or blown head gasket. The head gasket is easy to check, fill the radiator to the top, let the engine idle and check to see if you have bubbles in the top of the radiator neck. You must keep the radiator filled to the top to see the bubbles.
You could get hold of a a radiator pressure flusher and reverse flush the radiator and engine block.
You may just need to replace your bottom radiator hose. If it becomes soft or the spring has corroded at high engine speed the hose may collapse and restrict water circulation through the water pump and cooling system. I don't think this much of a problem though as our bottom hose is 2" diameter and quite short and I doubt you would call yblock water pumps high flow. The thunderbird further reduces efficiency by having the spacer behind the pump.
You may need a reliable infra red heat detector to properly check the radiator efficiency.
 
ok, the rad is hot all over which means water is circulating, just not being cooled, fan problem? no shroud?
 
Check the exhaust system. It is possible an animal got into the pipes and has clogged up the system. This is not unheard of., especially if it starts overheating all of a sudden at the start of a new season.
 
I forgot to add - check the exhaust control valve on the right side. This may have frozen in a closed position
 
I have made a little progress although the car is still running too hot.
I have replaced the exhaust system and advanced the timing a bit. An old time mechanic still thinks it is the radiator. Really don't want to have to take the tanks off, but I will if necessary.
Had an interesting experience replacing the mufflers. They were Lifetime guaranteed by Midas; no cost for mufflers, clamps or labor. They gritted their teeth a bit, at the free labor, but did the job.
 
Haha, on the midas muffler thing! I also had them on my bird from probly 1968 til around 2006. Definitely got my moneys worth on that first purchase!

Have you tried my backflushing method yet? It's cheap and easy to try.
 
I emptied and refilled the cooling system and it only would take 16 quarts! Specs say 21 Quarts with heater, which I have. I think maybe the back part of the block is partially blocked so the coolant can't get back to it. Have read that the 312's sometimes rust up around the cylinders pretty bad.
I haven't tried the back flush yet. Last time I filled the system with water and ran it till it was almost pegged HOT, when I opened the block drain *****, steam blew out!
I think I'll try Evaporust in the block. Have read pretty good things about that stuff.
Any comments?
Royal
 
If you had the radiator cap on, and it's holding pressure, the boiling point was raised. Given you're in CO., I suspect you are a ways above sea level, so water boils at less than 212F. When you open the petcock, and take the pressure off, the water immediately becomes steam. My experience with my 'bird is that getting all the air out of the engine, heater, and radiator takes a bit of running and heat/cool cycles.

I think the idea of the back flush is good. I've never used Evaporust, but a cleaning product might help.

A bit off topic, but you can buy infrared thermometers pretty cheap in the cooking section at Amazon.com. They work fine, generally within a degree or two of expensive ones. And your pancakes come out perfect when you check the griddle temperature. Let's you read the temp at the tsat housing, upper lower radiator, etc. Much more accurate than the factory gauge.
 
Royal, you can remove the back freeze plugs to clean out rust deposits that build up there, use a high pressure water nozzle, one with a small tip so you can get it up inside the block thru the freeze plug hole, you will be surprised how much gunk that builds up in there, it will look like mud
 
A whole list of questions came to mind - Do you still have the three blade fan? How about the factory fan shroud? Is the spark advance actually advancing? Which radiator cap is on there - what pressure? Do you still have the rapid warm-up exhaust valve on the RH exhaust manifold - does it function? Remove or wire open.

Any internal gunk removal activity you can do - will all be for the good. Locate a reliable radiator shop and take yours over there for a thorough check.
 
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