Electric -vs- mechanical water temp gauge

When my mechanical water temp gauge crapped out a few months ago, I replaced it with an electric unit. The main reason was cost ($72 compared to $40 for the electric). However I noticed that the electric gauge likes to jump around a bit. Is this normal or should I check my grounds etc..

 

sounds to me like check your grounds. but i bet someone will tell you im wrong

 

I like the electrical gauge. It's easier to hide the wire. I never liked the funky wire that screws into the manifold. They say that the mechanical one is more acurate, but the electrical Stewart Warner gauge is good enough for me.

 

prefer electrical: keeps leaks under hood where they belong, as instead of my lap.

 

$72 seems awful high for a mechanical gauge. I bought Auto meter 2 5/8" mechanical gauge at Summit for around $45 IIRC. I personally like mechanical gauges (just personal preference.)

 

I like mechanical, my electric oil pressure gage in my YJ crapped out yesterday i dont like em, just my 2 cents

 

I have always used mechanical gauges when replacing factory style electrical, I have never in 25 years had a mechanical gauge rupture and leak in the passenger compartment or under the hood, and actually until I joined this jeep board have never heard any of my racing buddies or other friends say anything about having one rupture and make a mess.
I have sen them kinked but they have always been replaced at the time of the kink because they did it while working on the motor and were aware of it.

 

If you use the plastic oil line, keep it away from the exhaust manifolds. That's one situation where it will leak!

So what's "mechanical" about a temperature gauge? How does a temperature gauge make a direct mechanical reading of the coolant temp? Electrical is obvious - thermocouple - but to be mechanical, you'd need a bimetallic coil or some such in contact with the coolant.

 

Tim, ha ha I know all too well about that plastic oil pressure line hitting the manifold. What stinks is that I had to buy an entire new gauge to get a replacement plastic line. :evil:

On the mechanical temp. gauge, there is that coil thingey that recesses below the surface about 1" and does make direct contact with coolant when screwed in the manifold. HTH.

 

Only thing I can imagine is that the bimetal coil thingy is attached to a stiff wire that goes all the way to the dash pushes and pulls the gauge needle. Doesn't inspire a lot of confidence - I think I'd rather have a thermocouple.

 

Mechanical gauges are almost always more accurate than an electrical, unless you can tune the thermocouple for an exact response in its particular application, I have seen 2 of the same T/C side by side gives as much as 10* temp difference.
I work with T/C everyday in my job and have opened brand new ones only to throw them in the trash for giving faulty readings and replace it with one that is more accurate.

 

So the vapor goes all the way from the sensor to the gauge, where it moves the needle. Interesting.

 

Hippo, Hippo, Hippo. . .

Have I not taught you anything! Ditch the plastic line and go copper. You can buy the kit for like $20 at your FLAPS.

 

Didn't know that. Gracias!

 

I am very happy with my electric temp gauge. Hasn't let me down yet. (just my humble opinion)

 

Doesn't the capilary tube of the mechanical gauge, have a liguid in it similar to a thermometer? As the fluid heats and expands it puts pressure on the half moon shaped tube inside the gauge, which expands and moves the needle? not sure just guessing.

 

Mike's quote says that there's vapor involved. Could be that the vapor bulb is immersed in the coolant. Expansion of the vapor pushes the column of liquid through the connection into the gauge.