VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 29 Temperature Gauge Test ?

Does anyone know how to test the temperature gauge on a 29? I get no reading at all.
The sending unit seems to work. I opened the unit, heated the sensor, and watched the four internal prongs move out to touch the surrounding probes.
Regards the Temperature gauge, I tried a continuity test between the two soldered ends where the hair like wires are mounted, and did not get continuity. Then I took the gauge to a local shop. They were likewise unable to get current across the coil, but said they were not sure that is the proper test (gauge is too old for their expertise).
Any help you can give will be appreciated.

I have the same problem and tried the same things. I put a multimeter across the sender unit while heating it on the stove and confirmed the resistance changed at about the right temp. However the gauge appears to be open circuit so am assuming that is faulty.

So would also love to hear any advice?

I have these sending units NOS if you find that you need one.
bwbugay@aol.com

connect the two wires at the sending together and ck gage should read hot. if not gage bad. oh also ck wires for continunity to and from gage.

Woohoo - I got my temp gauge working today.

The key bit of info I got from here was how to test the gauge (ground the sending unit wire), so I bought another gauge on ebay awhile back. It needed a little tweaking to get needle bent in right place, but I spent a few evenings fiddling with it until moving freely and setting on LH (cold) stop when stationary. Installed in the car today and went for a run and it works great.

It's the one thing on the car that has never worked (for last 10 years at least), and I had a motometer on it anyway so was not a big problem, but feels great to finally have it fixed. I find its sometimes the little jobs that I get the most satisfaction from.

cheers
Barry

Barry;
What temperatures give which readings? Guess you could call it a semi digital heat indicator, you only get 5 readings. No where do I find which temperature should give you what reading. Does the Motometer read in degrees? How do the indications on the Motometer compare the heat gauge?

Sorry Bill but I did not record the temperature settings when heating up the sensor on the stove. I was more interested in getting it working than the specific temp settings, but I suspect others will have been more diligent than I.

My unscientific method was to also throw a new 180 degree thermostat in the pot, and the first sensor change was just after that started to open, and the last sensor to close was not until the water was boiling. Which all seemed about right to me, so I then turned my attention to the gauge.

Personally I do not find the Motometer very accurate - gives a general indication only, and when the motor is cold to warm you can guess as accurately by putting a hand near the engine. I don't generally have the radiator topped right up so that the bulb is sitting in the fluid, and I don't think the air temp in the top of the radiator is a very indication of water temp when the car is running. After it has been sitting for a minute or two then I think it gets a bit more accurate, and is when I find most useful to check.

However my theory is that where it does help is if the engine gets very hot, as I doubt I could guess the difference between 190 and 220 degrees, but fortunately I have never had the chance to check. By then you can probably see steam out the top anyway.

However, I am very happy to be corrected by folks with far more experience with old Chevies and motometers than I.

I am out for a run on Sunday so will record the Motormeter reading and compare with the temp gauge, as I am now curious and thanks for asking.

cheers
Barry

There are four bi-metal strips on the 1929 electric temperature sending unit and each bi-metal strip registers a different temperature on the temperature gauge.

The four bi-metal temp sensors end up giving five readings. When its cold they are all open giving the first reading (cold). Then come the next four, each indicating some warmer temperature, the last one being a short, indicating you are just about to boil over, (or its already too late). What I am asking is at what temperature does each bi-metal sensor activate at. Each sensor contact has an adjustment screw so that the temperature at which each sensor makes contact can be set. Mainly the normal temperature setting and the too hot setting are what I need to set. With a 160 degree thermostat installed would a normal reading be at 155, or 165 degrees. Since water boils at a lower temperature at altitude what temperature should be giving an overheat indication when climbing mountain roads.

Do you still have one? Mine gauge at the dash is not working on my 1929 Chevy 194 6 cylinder

If so what are you asking for it?

You can email me

davidcarmell@hotmail.com

Thanks Dave

wow, that post is almost 11 years Old !!
maybe you will be lucky... there was a guy looking for one recently, and one came up on eBay

Refer back to the 2 part article in the G & D about rebuilding both the gauge and the sending unit. It also gives troubleshooting tips. Art

G&D issue(s) for this rebuilding and troubleshooting info?
I haven't seen a way to 'search' the G&D for this info such as this. Is it possible?
Many thanks.

Larry c

uhhh...I just found the G&D issues (Aug and Sept, 2014) in another Forum thread. Thanks anyway.
Larry c

Hello Larry,

I sent you a pm.

Art

Hi Art,
I responded via pm.
Thanks.
Larry

It can help to use an ignition point file to lightly clean the bi-metallic strip contact points. Or an emery board nail file.