I am considering removing the freeze plugs and to inspect the coolant passages and clean if necessary, as described in this article.  Has anyone tried this?  Any suggestions?  I am not going to remove the engine.
https://www.ctci.org/gilsgarage/1955-56-57-thunderbird-overheating/  (see "Plugged Water passages")

Just removing and replacing the core plugs in the car is a pita. If it’s rusted bad enough to go into the passages, I’d have it down to a bare block. I’m not saying it can’t be done, just that I wouldn’t try it. I’d run a flush through it first and see what I had. I’d also be worried about knocking stuff loose that I didn’t get out, and then having it plug the radiator with everything together and in the car.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Is the car a BIRD and you are having overheating problems?

The condition shown on the BIRD site is years of cooling system neglect. Once it builds to that point, it will be difficult to fully flush without tanking the engine. It will also be in the cylinder heads.

____________________________

If you pull the freeze plugs put a finger in the hole and reach down. You will probably find rust and scale almost level with the hole. That is a collection point in the Y-Block that will only get removed if the engine is stripped down and having the bare block cleaned and flushed. First go through the rest of the cooling system to make sure its efficient. There are a lot of Y-Blocks on the road with the water jackets full of rust that still run cool. I had my block flushed and added an aluminum radiator with an electric fan. It runs about 160 all the time with a 190 thermostat.

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Yes it's a 55 TBird.   It's not overheating, it's vapor locking.   The vapor lock seems to follow the temperature gauge once it gets over 200 degrees (not sure of exact temp).   I am using an after market CASCO gauge and sender

I've been through the entire fuel system multiple times and I am fairly confident it's caused by heat.   I'm in located NJ drove the car last year in 95 degree weather with the AC on without any issues.

I pulled the 4 plugs.   First I flushed each plug opening in the block with a garden hose.   Then I connected the hose to the heater hose outlet on the intake (hopefully this cleaned the water routes in the head (??) and ran about 40 gallons of water out the freeze plug holes until the water was clear.   After 10/15 gallons the water was very clean.   I also used a small magnet and fished out whatever particles I could reach.

Today I will start installing new plugs

"Yes it's a 55 TBird.   It's not overheating, it's vapor locking.   The vapor lock seems to follow the temperature gauge once it gets over 200 degrees (not sure of exact temp).   I am using an after market CASCO gauge and sender"

The fuel vapor lock/phase separation is caused by excessive engine compartment heat (the BIRD has a very poor engine compartment air flow).

There are many corrections that can be done to have one cool efficiently. The BIRD had design flaws (cooling system) and there are upgrades that can be done to cure them.

____________________________

I already have the paragon spacer, high volume water pump, auxiliary electric fan, 6 blade mechanical fan, re-cored original radiator.   Something has changed in the car because I didn't have any issues driving in much hotter weather last summer.

Did you check the timing and the thermostat? It could also be a faulty gauge/sender.

"auxiliary electric fan, 6 blade mechanical fan"

You have a mechanical and electric fan? Is the electric mounted in front of the radiator? If so, it blocks air flow through the radiator. All of the front sheet metal and shrouding is on the car?

You have the upgraded WP spacer and a HI-FLOW PUMP? Did you rework the volute opening on the front cover? You also need (IMO) a wide mouth thermostat.

The way FORD positioned the WATER TEMP SENSOR on the FYB, it will not give you a true coolant temp reading.

AND, as mentioned above, if you are still running the LOAD-O-MATIC DIST, if defective will cause overheating (poor timing advance).

Is this BIRD a survivor, restoration, resto-mod or just driver?

____________________________