Temperature Gauge Failure

[Bob Bidonde]

In May of 2022, I installed a Rex-A-Co temperature gauge in my Victoria. In April of 2024, after 1642 miles of driving, I noticed that the gauge stopped indicating the engine's coolant temperature. The temperature probe has developed a hole in it that enabled the ether gas to escape. I am replacing the Rex-A-Co gauge with an APCO gauge.

Has anyone experienced this probe failure?

 

[katy]

Have you checked the PH of your coolant?

 

[Vern]

Bob, depending on the cost of the Apco gauge, if you want the other one repaired, Ron of Williamson’s Instruments is the man.

 

[Tom F OHIO]

I have a Rex-A-Co gauge also. Mine sets at 100 degrees cold. I called them and they said that wouldn't matter. Do you think this would give me a false reading. Not sure if I should replace it or not.

 

[katy]

Put the sensing bulb in a pot of water, watch the temperature reading as you bring the water to a boil.

 

[Bob Bidonde]

I replaced the Rex-A-CO Gauge with an APCO Gauge. The Rex-A-CO uses an Ether gas filled probe (photo on the right) & line to the gauge head. The Rex-A-CO gauge head reacts directly to the increase in pressure of the Ether as it absorbs heat from the coolant. On the other hand, it appears that the APCO Gauge has a metal [robe & wire heat conductor that the gauge head reacts to. In my opinion, the APCO Gauge is more rugged, more reliable & a more appropriate dial indicator.

 

[Gene F]

I have a Rex-A-Co gauge also. Mine sets at 100 degrees cold. I called them and they said that wouldn't matter. Do you think this would give me a false reading. Not sure if I should replace it or not.

Who did you get that thing from? I never heard of such a thing. How old was it at the time?

 

[The Master Cylinder]

It only took 5 months to eat thru that bulb? What are you using for coolant? I think I would check the pH of the coolant.

I always use SW gauges, never a problem. Plus I like the 270° needle sweep.

Edit: I see Katy already suggested this.

 

[Tom F OHIO]

It was almost a year old. I called the company that makes it and that is what he told me.
I got it from one of our suppliers. I probably got screwed on this thing.

 

[The Master Cylinder]

I have a Rex-A-Co gauge also. Mine sets at 100 degrees cold. I called them and they said that wouldn't matter. Do you think this would give me a false reading. Not sure if I should replace it or not.

Does a Rex-A-Co gauge even read lower than 100°? Only way to know if it is reading orrectly is to test it. Water boils at 212°F at sea level.

 

[Bob Bidonde]

My Rex-A-CO Gauge was a new reproduction. The coolant in my car was water with some Barr's Stop Leak. The hole in the probe was a solder joint. I suspect the solder may have had a lower melting temperature or the acidity of the coolant corroded it away or maybe both effects were the cause of hole. In any event, the APCO Temperature Gauge has a more rugged operating concept.

 

[Benson]

...

 

[Tom F OHIO]

Does a Rex-A-Co gauge even read lower than 100°? Only way to know if it is reading orrectly is to test it. Water boils at 212°F at sea level.

Mine is exactly like the one in the picture. But sitting cold the dial is centered between the 90 and 140.

 

[Mike1291]

Plain water!

No wonder that we see SO MANY engine blocks that are so badly rusted from the INSIDE that they have cracks on the outside!

The MARC website states that anti-freeze is NOT recommended and to just use plain water. Where did the myth come from that anti-freeze is bad for the Model A?

The website also fails to recommend adding a rust inhibitor...

 

[ModelA29]

The MARC website states that anti-freeze is NOT recommended and to just use plain water. .....

Maybe they are looking to protect the paint on their members cars when they boil over......
I run 50/50 distilled water and anti freeze in mine with it's pressure radiator. Stays at 160 even on the hottest SoCal days.


Antifreeze also contains inhibitors that prevent corrosion in your cooling system and biocides to prevent microorganisms from growing inside it.

 

[The Master Cylinder]

Where did the myth come from that anti-freeze is bad for the Model A?

Some say antifreeze is bad for your babbit bearings. I say if you have antifreeze in your oil, you have bigger issues to address.

Maybe they are looking to protect the paint on their members cars when they boil over......
I run 50/50 distilled water and anti freeze in mine with it's pressure radiator. Stays at 160 even on the hottest SoCal days.

Antifreeze also contains inhibitors that prevent corrosion in your cooling system and biocides to prevent microorganisms from growing inside it.

Antifreeze also raises the boiling point of your coolant. I run 50/50 antifreeze, non-pressurized. Runs at 175°f.

 

[700rpm]

I used denatured alcohol as antifreeze from 1961 to about 2000 because of the cautions about babbit damage in the case where anti freeze might have leaked into the oil. It was about that time when newer types of commercial antifreeze came to my attention, and I have used that ever since. Denatured alcohol got more expensive and harder to find in quantity and I worried about it being boiled out anyway.

 

[Dino's A]

Or you can use distilled water and soluble oil aka: stop leak, water pump lube.
That was the combo that was used 30+ years ago.