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'41 Cadillac - Overheating??


Guest jimstulga

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Guest jimstulga

Looking for some experienced advice for my problem of possible overheating. I have a restored stock original '41 Cadillac owned by me since 2009. The previous owner gave me his receipts for work including one for a radiator re-core from 2001 costing over $500. Probably only a few thousand miles on the car since then. I had the water pump rebuilt by a company I used before. The temp gauge was replaced a few years back but was not calibrated right so the car always read "cold". I recently had that corrected and seemed ok through the cooler Spring weather. Yesterday, took the car out for a long ride at high speeds and 80 degree weather and it reads "hot" but does fluctuate a little bit during stop and go situations, but mostly the needle is all the way over to the "hot" side. Also, the thermostatic louvers in front of the radiator are working fine. After I got home and car off, noticed some anti-freeze discharging from the radiator overfill side hose every now and then totaling maybe a two cup puddle on the garage floor. After cool, I checked the rad level and it was pretty high. I wouldn't add more water from the appearance. My question is, if the car was truly overheating, should I be seeing steam or hear something different in the way the motor is running? It seems to be running fine.

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Guest jimstulga

Infrared Thermometer sounds interesting, but am I measuring the temp of the actual motor? If yes, where do I place the thermometer on the motor to read it and what temperature is correct for a fully warmed up '41 Caddy engine? Thanks!

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Guest bofusmosby

To address the coolant leakage, this may not be a problem. I have a 37 Pontiac, and after I got it, I noticed that the radiater was a bit low, so I topped it off. Well, when I would run/drive the car and the engine heated up, there would be some coolant come out of the over-flow tube. I finally realized that I must have been filling it up too high, so when I left it alone, it never lost any more coolant, and the engine has always stayed at the 180 degree level.

As far as the over heating goes, with my experience, the valves would become noisey, with a bit of clanking. If your car is truly over heating, shut the engine off, then in about 30 seconds to a minute, try starting it up again. If the engine is too hot, the starter will sould sluggish, like the battery is weak, due to the high heat. I like the idea suggested to check the actual engine temp, and I too would like to know what would be the normal reading with this.

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Guest Commodore
Infrared Thermometer sounds interesting, but am I measuring the temp of the actual motor? If yes, where do I place the thermometer on the motor to read it and what temperature is correct for a fully warmed up '41 Caddy engine? Thanks!

Yes, you would be measuring the temperature of the actual motor. When the motor is fully warmed up, the heads and the block should be close to the same temperature. The temperature of the engine depends on the thermosat installed but should be in the range 160 to 180 degrees. Try placing Infrared Thermometer on the area where the temperature sender is installed. As a note if your '41 Caddy did not come from the factory with a pressure cap, Hot on the gauge will be about 200 degrees. Remember water boils at 212 degrees. So at about 200 degrees the car would be boiling over.

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Guest Douglas Houston

The temperature sensor on the engine will show full "hot" on the dash gauge if it fails. I've had onlym one fail, but that is the way they go bad. You have already confirmed that the system is not overheating. Even the radiator shutters are operating. You might check with your nearest NAPA store to see if they have it in their oldest books. I've always been lucky with them.

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Guest jimstulga

Thanks for the additional info. I've heard bad comments about the new temp sensors and think that is what I have for lack of being able to find a NOS one. My dash gauge went all the way to "hot", but did move down and back up as driving conditions changed.

I bought an infrared temp tester, but there's been so much rain here, haven't had a chance to get the car out to test it yet.

Jim

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When you get the tester check the temp at the housing and the lower hose to see if there is restriction. Turn on the heater for a second test. The 41 indeed had a pressure cap... A 9lb AC RC-7. A cooling system pressure test may be necessary for later. Leave some space in the top rad tank for expansion. Ron

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