stuck\seized temp guage

[Guest 50Plymouth]

My temp gauge always reads all the way past hot, car on or off. Never moves; is my gauge seized\stuck or is there a common problem that causes this?

[randroid]

50Ply,

The heart of the temp guage is what is called a "Bourdon tube", which is an arc shaped flat tube connected directly to the bulb in the block. When the ether in the tube gets hot it expands, which straightens the tube slightly, which causes the needle to move. Sounds like a Rube Goldberg setup but is straightforward and simple. Most likely what happened is the engine was over-heated at some point and stretched the tube beyond its limit, and you should feel free to try to re-bend the tube back to its original position as many times as it will take until you're satisfied that it cannot be done, which it cannot.

Wally World sells a replacement guage for $10 that will work fine until you're ready to shell-out the $125 that Andy B. gets for an NOS replacement.

-Randy

[Al Martin]

Hi randroid

My temp gauge is not working either.

The temp guage from Wally World that sells for $10

where can I buy it?

Could not find it on the Web.

How did you mount it to the engine?

Al

[Jim Saraceno]

Don't forget, there is a section in the "Tech Tips" section about how to replace a sending unit and I believe Tod Fitch's site "Plymouth, the First Ten Years" has a section on how to repair a unit.

[Guest 50Plymouth]

Indeed your right, there is section under the tech tips regarding this.

http://www40.addr.com/~merc583/mopar/framesets/techtipframeset.html

Tod Fitch's great article is here:

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

If i didn't already have ruined line to the gauge already, then I didn't help matters by installing my firewall mount booster and dual MC which fights for space with that flexible line, which I dumbly assumed was for oil pressure or something at quick glance.

Ryan

[Guest 50Plymouth]

After reading both articles twice I'm still wondering, is there a way to check whether the problem is the mechanical bourdon tube versus just the gauge indicator itself.

Based on randoids suggestion of overheating, I'm not quite picturing the "stretched the tube beyond is limit" part? Does a kink or overheating lead to the ether leaking? If something was then disconnected why didn't the indicator fall back with less pressure. If the bulb got locked because of corrosion like the Tod Fitch article suggests, than my indicator would probably not be stuck all the way past Hot. Looks like Walmart may make another $10 off me.

[Norm's Coupe]

I doubt that the problem with your gauge is the tube. If the tube were kinked and leaking, the gauge should read "0" all the time, not overheating. Sounds like the gauge may have just went up that hot at one time and possibly sprung it.

At any rate, the one from Walmart will work fine. It's hooked up the same way as the original gauge. I did have to either step the connection to the block either up or down with a coupling, forgot which way off hand. You can buy couplings at any hardware store to do that.

I have an extra original working gauge in the cabinet for my P15. However, I left the one from Walmart hooked up because I trust it more.

[Guest 50Plymouth]

My local super walmart doesn't carry any gauges, but I picked a cheap mechanical gauge from the local discount auto supply. So... I mounted the little gauge below the dash next to the climate controls hooked the bulb into the block, tightened up, start the car, confirm no leak and waited. Waited... Waited.

Car ran for maybe 10min and the gauge never went above the min didn't move at all above the min. 130deg. setting. ARRGG..The manual offers zero troubleshooting. Would a thermostat problem cause this?

[greg g]

You can check the gauge by immersing the bulb in a pan of simmering water along side a common cooking thermometer. Are you sure you are getting good water circulation int he head where the temp gauge sits? This is usually the warmest spot on the engine. If you are running without a thermostat, and just idling, you may not get much above 130 /140 degrees. Another check is to insert the cooking thermometer in the radiator fill. This will show the temp of the coolant in the radiator (usually cooler than engine temp)

[Norm's Coupe]

Check the tube from the gauge to the block. It is possible that you kinked it when you installed it. If you did, the gauge is probably toast and you'll have to pick up another one.

[Guest 50Plymouth]

Well the tube is plastic outer with no wire covering and it was wrapped tightly and and bound with a wire wrap in the the dinky plastic packaging so at least the company wasn't concerned about kinking that way.

Why might I not have good coolant circulation there? air pockets ever? BTW the old stock bulb was corroded and stuck in the adapter. I did loose a lot of fluid just before because it spilled when removing the adapter and I replaced 3 heater hoses. I added more than a gallon of water to replace.

duh, I too tired I don't know why I didn't think of testing that way especially when I just read it a day or so ago in Tod Fitch's article Guess I should have gotten my better half a cooking thermometer for mother's day

[greg g]

rust scale can cause flow problems. Do the check with an alternate thermometer and then post the results.

[Guest 50Plymouth]

any good tech tips for temporarily plugging an opening such as where the temp. bulb goes? oh wait.. I guess a correctly threaded and sized bolt would plug pretty good. well, on the same thought - are there any other favorite temporary plugging solutions for coolant related places when swapping something like thermostat or rad. hoses or do you just let it all drip and drain down.

[TodFitch]

  50Plymouth said:

any good tech tips for temporarily plugging an opening such as where the temp. bulb goes? oh wait.. I guess a correctly threaded and sized bolt would plug pretty good. well, on the same thought - are there any other favorite temporary plugging solutions for coolant related places when swapping something like thermostat or rad. hoses or do you just let it all drip and drain down.

Not positive, but I think you will do better with a pipe threaded plug for the temperature gauge hole.

[Guest chrysleritis]

You know, my temp gauge was "seized up", "sprung", so it always read

past "Hot". I just pulled it out of the dash, and tweaked it back into position, and it has worked fine ever since. It's not calibrated, exactly, but it

definitely gives you a good indication of running good/too hot/not yet warmed up. When they overheat, the needle just gets stuck, semi-permanently.

[Guest 50Plymouth]

  chrysleritis said:

You know, my temp gauge was "seized up", "sprung", so it always read

past "Hot". I just pulled it out of the dash, and tweaked it back into position, and it has worked fine ever since. It's not calibrated, exactly, but it

definitely gives you a good indication of running good/too hot/not yet warmed up. When they overheat, the needle just gets stuck, semi-permanently.

Looking back I wish I had at least first tried exactly what you said here! Instead I replaced and broke away the old tube and plugged in my new cheap replacement. BTW, do the bulbs ever get "froze" or stuck in the head in such a way that they don't function even though nothing leaked? Mine looked seized in the fitting and I didn't understand if that mattered concerning the expansion or flexing of the chemical inside.

I ran my car after installing and needle never moved as mentioned earlier, so now I will test it out of car or check rad. since my wife got a nice cheapo cooking thermo.

[Don St Peter]

On my 40 Ply., my guage was sticking above 160 deg regularily. I then determined that the needle was sticking and/or rubbing against the glass around that point. Adjusting ( bending slightly) the needle fixed the problem.

Don

[chesterx]

What would make a temp gauge needle read high when engine temp is OK? My gauge seems to start out ok and reach normal temp area but then runs past normal area and climbs to 3/4 howards hot. Engine temp is always the same, just over 200F measured at the sending unit area.

[Plymouthy Adams]

the 200 degrees would explain the 3/4 hot reading...just 12 from boiling...you may have some blocking up there prevent flow about the unit..sad part is that if not careful, the removing of the bulb may cause tube to break..this is a very tough item to remove due to rust over the years...about the only way to verify that you may have a blockange is to remove the sender...mount another there for double checking actual temp...

[Guest 50Plymouth]

  50Plymouth said:

Well the tube is plastic outer with no wire covering and it was wrapped tightly and and bound with a wire wrap in the the dinky plastic packaging so at least the company wasn't concerned about kinking that way.

Why might I not have good coolant circulation there? air pockets ever? BTW the old stock bulb was corroded and stuck in the adapter. I did loose a lot of fluid just before because it spilled when removing the adapter and I replaced 3 heater hoses. I added more than a gallon of water to replace.

duh, I too tired I don't know why I didn't think of testing that way especially when I just read it a day or so ago in Tod Fitch's article Guess I should have gotten my better half a cooking thermometer for mother's day

Okay, when last running the car I shared earlier here that my temp gauge never went up above 130. So now I removed it and checked it in water on stove with a cooking thermometer for double checking accuracy. The unit is fine and and accurate.. So why does my temp not go past 130 even with car running for 10min at idle? Thermostat stuck open?

Ryan

[chesterx]

Thanks much,

I replaced the temp. gauge with a $15 one and the engine temp. sits between180 and 190F. Seems to be just fine. I do think that I'll go back to the 160 degree thermostat just to calm myself. Off to find a new one.