Checking radiator for overheating problem with 1956 Thunderbird

[zuburg]

I am trying to diagnose overheating problem with newly remanufactured 292 in a1956 Thunderbird. I took some infrared temperatures of various places to try and determine if new thermostat (I believe I used a 180 degree) and new water pump are working, as well as is the radiator restricted. Here are the temps:
225 Timing cover
216 Thermostat housing
198 Top radiator hose close to water pump
194 Top radiator hose close to radiator
220 Top radiator inlet tube
197 Water pump
174 Lower radiator hose
172 Lower radiator outlet tube
160 Heater hose from water pump
170 Heater hose from heater control valve

What do these temps indicate? The only thing that makes any sense is a restricted radiator, as everything else in the mix is new. I had the radiator cleaned out and pressure tested years ago, but while it sat in my garage waiting for the delayed new engine installed, mice found their way into the lower inlet tube bringing bird seed with them. I poured over 50 gallons of water through the radiator until I saw no more bird seeds, but I wonder if some could have gotten stuck in any tubing? Some of the seeds were shells from sunflower seeds. Is the tubing small enough that they could get stuck?

I also read after taking the initial temps that I should check temps on the upper, middle and lower part of the radiator looking for cold spots. It was 5-10 min. Before I read that but went ahead with taking the temps without starting the engine again. The temps got progressively less as I went from top to bottom. Is that typical? or should they be close to the same throughout?

 

[Dobie Gillis]

On a down flow radiator you should see a temperature drop from the top to the bottom, so it seems to be working. How well it's working is a horse of another color. Since the mice got in there and brought their buffet with them I think I'd have a radiator shop check it out and make a recommendation.

 

[KULTULZ]

I also read after taking the initial temps that I should check temps on the upper, middle and lower part of the radiator looking for cold spots.

If any cold spots are found in the core, it indicates blocked tubing at that point. Maybe it is safest to have the radiator flow tested and then roded if necessary.

Look through the upper tank radiator cap opening at the size of the tubing and you will realize it doesn't take much to cause blockage.

Is the car overheating? In traffic or highway?

Many factors in the BIRD COOLING SYSTEM design can cause overheating. It wasn't all that well designed.

 

[zuburg]

I wasn’t on the highway, but also not in traffic. I was driving in town with little traffic and 45mph for much of the time.

 

[Dobie Gillis]

In case it needs to be rodded out here's one way to do it:

https://www.youtube.com/watch?v=mcH-H9B1Rc8

 

[zuburg]

Wow. Is this what radiator shops do as well?

 

[Dobie Gillis]

Essentially, yes. There are different methods. If you check YouTube there are several videos about it.

 

[dmsfrr]

Is the thermostat the type with the standard opening or an oversized one?
The version with the larger opening may allow better flow out of the engine into the top of the radiator. The side of the thermostat with the coiled spring faces into the intake manifold.

https://www.ctci.org/1957-thermostat/

https://www.classictbird.com/Thermostat-Large-Opening-170-Degrees/productinfo/8575C/

 

[KULTULZ]

The extension is threaded into the valve and can be removed by turning it counter clockwise. Once removed the NAPA # 6 thermostat can open fully. Removal of the extension does not effect the operation of the heater control valve.

Gil Baumgartner

That statement is not quite true. He should have added IMO.

 

[40cpe]

Your temperature drop of 48 degrees from the top (inlet) tube of the radiator to the bottom (outlet) indicates excellent cooling within the radiator. The even, steady drop and absence of cool spots top to bottom is consistent with good cooling. I've also read that the infrared thermometers don't read accurately on rubber, which I assume is the reason for the wide difference between the upper radiator hose and the upper inlet tube.

 

[zuburg]

Thanks, that’s the kind of info I was hoping for, before I start tearing into the radiator. Maybe I should check the thermostat first. Maybe it is stuck closed?

 

[40cpe]

Thinking of some possible causes on a newly built engine and install: Sometimes the thermostats are installed backwards. the spring/pellet end goes to the engine. You seems to have coolant flow, so that might not be your case. You could take it out to eliminate it as the problem. Being a newly built engine, it could be exhaust in the coolant if a head gasket didn't seal. There are kits to check for exhaust gasses in coolant if you don't find another cause. Also check for cooling fan installed backwards.

 

[zuburg]

Follow-up on overheating problem:
Replaced new water pump with new high output water pump.
Replaced thermostat with large opening thermostat (Gil Baumgartner)
Drove car in 75 degree outside temp for 15 min. in very light traffic going about 45 mph most of the time, and the temperature gauge was steady about at the red line in photo (appeared to be about the thickness of the needle past the center of the large white line on the gauge. Continued to drive another 15 min. in some heavier traffic including some long red lights and the temperature climbed to a little above where the photo shows, but never got to the end of the large white line on the gauge. I drove home as it started to move towards the end of the large white line for fear it would overheat and force me to pull over in traffic.

Does this appear normal as temperature gauges go during operation? Or should the temperature stay closer to the middle of the large white bar in these conditions?

If it appears my car is overheating in these conditions, there is a chance we installed a head gasket upside down on the drivers side as we pulled this head and reinstalled to fix another issue. Just wanted to try everything else before having to go to the trouble of pulling the head.

One other question about the radiator. I was looking at the overflow tube coming out of the side of the neck where the radiator cap goes and noticed it was loose and a small piece of plastic tubing was inserted into the overflow tube and inserted into the hole in the neck, more or less attaching the tube to the neck. Is this how it is supposed to be or was this some kind of hack by the previous owner?

 

[dmsfrr]

It seems quite normal to me. Especially since the old gauges can be inaccurate & tend to read high.
The handheld infrared temp gun will confirm the readings you're getting. 180* to 200* on the thermostat housing is normal. Photo 3
If it isn't spitting out coolant it isn't overheating. Coolant level should be an inch or so below the filler neck when cold, to allow for expansion.

When installing head gaskets one of them should look upside down compared to the other, it's the way they're made. The matching squared off corners of both gaskets should peek out from the upper front corner of the heads when they're installed correctly. Photo 1

A short metal tube should be soldered into the radiator filler neck, with a flexible tube on it, leading off to the bottom corner of the radiator (photo 2) or an overflow bottle.
.

 

[zuburg]

Thank you DMSFRR. You don’t know how relieved I am to now know my head gasket is on correctly. Thank you for that picture.

Regarding the overflow tube, are you saying a very short metal tube is soldered to the filler neck, and then a flexible tube (rubber hose) is attached to that and routed across the top and down the side of the radiator? My tube is metal across the top and down the side. The end of the tube is wider than the rest of the tube and looks like it could be soldered to the neck.

Should I solder the existing metal tube to the filler neck?

See photos.
Photo 1: metal tube pulled out of filler neck with plastic tube still inserted. Notice the expanded end of the metal tube.
Photo 2: the plastic tube pulled out of the end of the metal tube.
Photo 3: A view of the hole on the side of the filler tube.

 

[dmsfrr]

I wouldn't be concerned that it's a metal tube as compared to a rubber one...
But the top end should be soldered to the filler neck.

For whatever it's worth... on my '55 radiator the tube seems to also be soldered to this raised area of the top tank, apparently for additional stability.
.

 

[Late model]

Your temperature drop of 48 degrees from the top (inlet) tube of the radiator to the bottom (outlet) indicates excellent cooling within the radiator. The even, steady drop and absence of cool spots top to bottom is consistent with good cooling. I've also read that the infrared thermometers don't read accurately on rubber, which I assume is the reason for the wide difference between the upper radiator hose and the upper inlet tube.

Your right about the problems with IR guns. This link pretty well explains them.
I was kind of wondering about the 48 degree drop. The normal radiator water temp drop is usually between 10-30 F. A large drop can indicate an obstructed radiator, the reduced flow receiving more than enough air causing the high temp differential. A low temp differential (10 degrees or lower) usually indicates low air flow. The radiator is not getting enough air for the conditions it's running in. In rare cases too high of water flow (no thermostat, over sped water pump etc.) can also cause a low temp drop. The water is passing through the radiator so fast there isn't time for good heat transfer.
To accurately diagnose overheating problems you need to know the radiator inlet and outlet water temps, the inlet and outlet cooling air temps, and the radiator flow.
That's an awful lot of work, and checking the obvious things first makes more sense, but at some point checking these things I just mentioned can help.
In this case if the drop is that high I would suspect that the mouse problem and the high temp drop are connected.
I would try to see if I could find a couple of thermocouples and an electronic
thermometer that read them and get a close check on the radiator drop. I use a couple of hose clamps to hold the thermocouples against the radiator necks just forward of the hoses and if the leads are long enough, carry the thermometer in the car.
Try and find a heating and air conditioning technician and see if they might be able to do a test for you.

https://www.fluke.com/en-us/learn/b...et-great-results-with-an-infrared-thermometer

Don

 

[Ford blue blood]

Do you really have an over heating issue? Are you loosing water? Have you tried just idling and watch the temp gauge? Will it blow water out sitting and idling? You will not hurt the engine if you let it sit and idle to see if it blows water. Just shut it off if that happens and wait for everything to cool off before you do anything else.

 

[zuburg]

Before I installed the high output water pump, it did overheat with the gauge going all the way to H while driving, and the engine starting to run rough. Radiator and hoses were very hot, and lots of pressure and steam in the radiator. I will try the idle test you suggest next. If coolant does blow out, will that be through the overflow tube or through the cap?

 

[Old Redneck]

My 56 T-Bird has a 292 bored out 40 Thousands. I just installed a new 4 core radiator, High output Water pump, Electric Fan and Air Condition plus a Over flow tank so I don't lose antifreeze. I am finishing up installing the Air Condition with the Help Dave Lyle. He sure know what to do from installing Air Conditioning in his 57 T-Bird. We are installing Insulation inside the floor completely so the inside will be cool when using the Air Conditioning. Yes also installed a Alternator 100 AMP. Lots of work. This T-Bird should not overheat now.