BearKiller

Less than a year old, EQUUS brand (I THINK), tested in a pot of boiling water prior to install, has been working fine, plumbed in next to the thermostat housing, sticking straight up.

A few days ago, I left the truck idling, while I ran in Advance, in near 100 degree heat.

When I came back out, after about fifteen minutes, the first thing I looked at was that gauge; it was laying flat on the bottom, like it was zero outside and the engine cold.

As soon as I moved the truck, the gauge came up to normal and worked fine for several days.

Now, it refuses to move off the bottom.

Is this something I can fix; or, do I fix it with one of the new ones I have waiting to be installed in some of these other trucks ??

It seems to me that when the weather gets HOT, everything starts falling apart; I am looking forward to winter.

Thanks.

Boatnik

The mechanical gauge normally uses a volitile fluid to put pressure on a bourdon tube. Usually something like alcohol. As temperature increases the fluid expands forcing the needle to move. It sounds like it has sprung a leak. I know of no way to fix it except replacement. If it had boiled the fluid or over deflected I would imagine you would be doing a major overhaul by now.

apwatson50

My AMI(autometer industrial) mech temp gauge also stopped working about a month ago, which was installed less than a year ago with less than about 5k miles. Same thing, one day looked at it and was sitting on the bottom. Once in a while now it will come up to about 140deg. I am now looking for an electric temp gauge.

dan1stgen

ive noticed that if you are very gentle with a mechanical guage they can last years but with something like a ctd with all the rattling and heat they product that little tube to the gauge is bound to wear out mine was in the truck when i bought it i performed this preventative maintenance. from past experience i found to extend there life you can rap the little coiled shield in plastic air line norm used in semi's for air brakes it prevents debris heat end kinking. havent had any issues with one since i started doing this

kjewer1

Another common cause of the coolant temp gauges bottoming out is low coolant level, with the cars at least. The air temp is lower than the fluid temp, so the gauge drops. At cruising RPM the pump can push enough water past the sensor to give a reading. Many people overheat a motor, then when enough coolant has been pushed out the gauge reads air and drops, so they think it fixed itself and keep on driving. This is where the head warpage and major damage happens. Worth checking the coolant level just to be safe.

BearKiller

I agree.

This is one reason why I question the wisdom of installing the pick-up in the most commonly used access port, high up on the engine, above the coolant level should it get the least bit low.


I intend to swap holes with the factory gauge sender, which is low down on the side of the block, and less likely to get high and dry.

PeytonMaterne

How many places are there to put a mechanical temp gauge other than the factory one at the rear of the head?