322 Aftermarket Temp Gauge

[Wooly15]

I apologize, I know there is a thread about this but I cannot find it again. I'm looking to install a temporary aftermarket temperature gauge and was wondering which ones will work with a nailhead. I'd like to use the existing hole for the factory gauge. My gauge is not working properly and I'd like to know how hot I'm running until I fix it. I thought I remembered reading that the sending unit bulb needs to be fairly long in order to read correctly.

 

thanks in advance,

Adam

[Ttotired]

All of what you said is correct, but any old aftermarket one will do. I am assuming your looking at mechanical ones?

I would leave the factory one in and put the second one somewhere else (note temps differ from different places on the engine) like the top radiator hose is a good spot, just slip the bulb into the hose at the thermostat housing with a blob of silicone sealant on the capillary tube to help it seal and tighten it up, let the silicone go hard over night or whatever, then check for leaks.

By the way, I had a hard time removing my factory one as it had built up a bit of gunk on it and was quite happy to stay where it was, so if you do remove it, be careful, they are fragile

 

 

[Wooly15]

I am talking about a mechanical gauge. Something simple. I'm going to have to remove my factory one to repair it eventually. At cold it reads N and running its slightly higher than N. I wonder how much of a difference of a temp reading there is between the upper hose and the head. Is it close enough to give me a good idea of running temp?

[Ttotired]

Actually, just below the thermostat is normally the best spot, so it will give the correct reading in the hose, but will basically stay on cold until the thermostat opens

 

[Wooly15]

All of the gauges I've seen have relatively large sending units. How would you get it in the water manifold without interfering with the thermostat?

[buick5563]

Wooly,

I wouldn't personally mess with two gauges. The mechanical gauge screws in to the original sending unit hole, but you need to add a washer between the top of the bulb and the bottom of the threads. A split lock washer that is smaller than the threaded portion will work. The reason you have to do this is that it doesn't seal because of the threads, it seals because of the flared portion of the bulb.

Does that make sense?

This will give you a good idea of how your car behaves. I had one temporarily installed and realized it was running exactly where I wanted to see the temps. Usually 180 driving and 210 maxed out when in traffic. 

[Wooly15]

Got it, I see what you're saying. Any idea what the thread size is for the stock hole? 

[buick5563]

I have used several different brands, all of which came from local sources (not fancy). They all came with adapters, which I believe I didn't have to use, because the smallest one fit. If I had to guess I would say 3/8" NPT (pipe thread).

[Wooly15]

Well, you guys were right...things' pretty fragile. I pulled a little too hard and snapped the wire off of the sending unit. Oops! . Would soldering it back work? I know it's nigh impossible to find a replacement. 

[buick5563]

Nope. You have to send the whole unit to be rebuilt. It isn't a wire, it is a pressurized tube.

[Roadmaster75]

May I suggest acquiring an infra-red thermometer that has a little red laser in it.

Go to Amazon, Harbor Freight, etc. $30 should get you a decent one.

This will allow you to take pretty accurate temperature readings at various locations

under the hood: top/bottom of radiator, thermostat housing, cylinder heads, water pump, etc.

I've never completely trusted ancient temp gauges and I throw the IR gun into whatever

old car I'm driving...just for a bit of extra peace of mind.

 

 

[Ttotired]

Without trying to sound like a smart donkey   that why I was suggesting putting the second one somewhere else. To get the one out of my 58, I had to destroy the core plug in the back of the head and push the bulb up from inside the head.

 

Have a look here and see if your able to give it a go, I have not done it, but it should work

http://www.ply33.com/Repair/tempgauge

 

 

[Beemon]

The cylinder heads are the same for both sides. Since it's already damaged, you have nothing to lose pulling the old sensor out of the head. Personally, I would have tried to remove the plug on the passenger head at the front of the engine first, then try and remove the temp sender on the driver head at the back of the engine. They're both probably equally hard to remove due to 60 years of being seated.

[buick5563]

I would have recommended the front passenger head, but the bulb won't reach. I've tried. 

[Wooly15]

Even though I broke the tube, there was just enough still sticking out that I could grab it with some pliers and go figure, it slid out no problem. I installed the aftermarket temp gauge to plug the hole. On a good note, my unmolested 322 still runs nice and cool! As long as my new gauge isn't lying. .