413 overheating or bad gage?

Joined
Jun 2, 2019
Messages
141
Reaction score
36
Location
Panama city beach
Ok, so I was FINALLY able to find the correct temperature sending unit for my 1964 300k with 413/w AC. BTW this motor only has 1 port for the sender(which SUCKS). However, I got the new one installed and hooked up a "equus" aftermarket electric temp gage.

I go to crank the car(it hasn't been ran in a week or so, so definitely cold) and it jumps straight to 160-180 degrees according to the gage. After it idles and drives about a quarter mile it hits 240, however it doesn't feel like its overheating.

I take an infrared lazer and the hottest Temps I get at the water pump, radiator, hose. Etc are only like 160-180 while at a straight 8 min idle.

So am I overheating or bad electric gage?

As always thanks guys, I wouldn't be able to build this car without yal!!
 
sounds like you have answered your own question. If the actual temp readings are good, then the gauge readings are not.
I'm not familiar with the aftermarket gauge you are using but it should have come with its own sending unit so its getting the right input. I suspect the original replacement sending unit does send the right info to that gauge.
 
OK awesome info, had no idea the sending unit had to match the gauge. BTW this brand is one of the el cheapo ones from auto zone

Just wasn't sure how accurate the infrared lazers were.
 
OK awesome info, had no idea the sending unit had to match the gauge. BTW this brand is one of the el cheapo ones from auto zone

Just wasn't sure how accurate the infrared lazers were.

Why the aftermarket gauge? Does your factory gauge not work? What happens when you connect the sender to the factory wiring connection?
 
OK awesome info, had no idea the sending unit had to match the gauge. BTW this brand is one of the el cheapo ones from auto zone

Just wasn't sure how accurate the infrared lazers were.

I learned that one with my 64 the hard way too Drew. Luckily when you buy Equus, you aren't really breaking the bank.
 
Haha yeah, and ripnator, the factory one isn't working.

I hear ya. . . My factory gauge ain't working right now either, so I ran a separate sensor from the front cover on my 440, and I'll tackle the factory gauge problem when I get into the instrument cluster. Don't know if your front cover is the same, but I bet is is. See the photos below:

img_20180929_112145373-jpg.jpg


img_20181110_161545500-jpg.jpg
 
Actually Rip, its not. On this 413 I can only find one port, and its very small and hard to get to under the AC compressor.

I'd love to run a separate mechanical gauge, however I've yet to find one that has a small enough probe to mount.
 
Actually Rip, its not. On this 413 I can only find one port, and its very small and hard to get to under the AC compressor.

I'd love to run a separate mechanical gauge, however I've yet to find one that has a small enough probe to mount.

You may need to rig up some kind of 'T' fitting to make it all work. And yes: The location under the A/C compressor makes it a real pain to hook things up. Fortunately, when I installed mine, I had not yet re-installed the the compressor. BTW, I used Autometer gauges.
 
So Mike, any input on any other brands of aftermarket gauges?

Hi Drew,

AutoMeter's, Stewart Warner's are a bit more expensive, but reliable I have found. Really it comes down to matching the gauge to the sending unit as was mentioned, rather than using the OEM sending unit to a modern gauge.
 
Make that '66 and newer. . .
Make that '66 and newer. . .

Mr. 413 is partially correct: If you have a gauge only w/o A/C, it's the small sender. However, if you have an A/C car with an idiot light, it appears that the larger sender is needed for '66 and up Chryslers. Also note that the cross-section of the cover in my post above is thinner than a non-A/C setup. The non-A/C cover is too thick and won't allow you to correctly mount the A/C compressor. Don't ask me how I know this. . .

img_20180922_141214110-jpg.jpg


img_20180922_122249838-jpg.jpg


As it turns out, both 383 and 440 engines WITH A/C use the housing with the 2 and 1/2 inch mounting boss. There is no special 440 engine power steering pump bracket. The bracket is the same for both engines. Its the water pump housing that is different.

Here is a shot comparing the two:

img_20180922_144601064-jpg.jpg
 
Hmm, interesting. I honestly plan on removing my AC, I know I plan on swapping out the water pump pulley, wonder if its worth replacing the water pump cover as well
 
Check your sending unit with an ohmmeter. Original sending units are as follows as would have been seen on the original gauge low first line should be around 74 ohms. Middle line around 23 ohms. Hot mark all the way to the right should be 10 ohms
So if your sending unit is reading lower than 74 ohms give or take 10 ohms it is likely your sending unit.
Check again when your thermostat first opens. (You will feel heat in the top radiator hose and radiator). It likely should read around the 23 ohm mark. If it is reading lower,more than 4-5 ohms less than 23 ohms, your sending unit may be reading high. Make sure your thermostat is opening at around the 180 degrees or whatever value your thermostat is.
Sorry I don’t know the exact table of ohms to degrees. Just going off factory gauges.
 
Hmm, interesting. I honestly plan on removing my AC, I know I plan on swapping out the water pump pulley, wonder if its worth replacing the water pump cover as well

If your A/C system is intact, I would just keep it, and when you are ready, have it repaired. Just disconnect the green wire from the plug wire that goes to the pump-pulley clutch. Frankly, the car is worth more with A/C, whether its working or not.
 
BTW, you think a T-fitting could work to fit a larger probe??

I'm sure there is a combination of fittings that will allow you to rig up both an idiot lite and a mechanical / electric temperature gauge. Also, regarding removal of the A/C: You live in Panama City, FL. Doesn't it still get pretty damn hot there ?!?
 
Back
Top