How To: C15a Wire-3 restoration

[Phil Waterman]

Hi Jordan

On the speedometer try loosening the cable nut on the back of the speedometer. My HUP with late style dash the speedometer doesn't like having the cable nut tight been that way since got it 40 years ago. Same problem with three different speedometers, if nut on cable is tight I think it loads the bearing on the little cup inside just enough so it rubs and makes the needle jump around. Loosening it a half to full turn seems to solve the problem.

One speedometer I had to replace spun up so hard that it rapped the needle around the limit pin.

On the thermostat did you say this was a new or old one and did we discuss exercising thermostats before installing?

Also do you have the steam relief valve open or closed? With my trucks I've found I get more accurate and quicker response from from the temperature gauge if the steam relief valve is just barely open, it helps the coolant flow up through the fittings and passed the sender.

Great work on your truck, I've really enjoyed following your progress.

Cheers Phil

[Bruce Parker (RIP)]

Curious about the heat. It seems to be under load and OK when at an idle. Blockage? Timing? Rich mixture (what do the plugs look like)? I've had that problem with Fords but have a hard time getting Chevs up to a working temperature. I look forward to hearing what the cause is. Is rad fluid making it to the overflow can? Why is the can on the outside?

[Jordan Baker]

Phil.

Ok thanks for the tips on the speedometer. I’ll check the nut on it.

My steam relief tube does not have any shut off. It’s always open.

Bruce,
Yes this was while it was under load. If it idles for about 10min the temp comes down to around 180. Then after about 10 min of driving it’s climbed back up to over 210. There is a chance it may have an air bubble in the system. Part of me wonders if the water pump is spinning too fast at the higher end and there is some cavitation going on or I’ve got a blockage somewhere. All things to investigate.

I do not yet have the radiator overflow can hooked up.

[David Herbert]

I would question the thermostat and then the gauge itself.

David

[Bruce Parker (RIP)]

Originally Posted by David Herbert

I would question the thermostat and then the gauge itself.

David

The 'how long can you keep your hand on the rad tank' test...when the gauge is in doubt. If it's really running at 220 you'll know pretty fast. Because of where the temp gauge is on a carrier and the difficulty in reading it I often resorted to checking the temp with my left hand on the upper tank.

[Jordan Baker]

Originally Posted by Bruce Parker

The 'how long can you keep your hand on the rad tank' test...when the gauge is in doubt. If it's really running at 220 you'll know pretty fast. Because of where the temp gauge is on a carrier and the difficulty in reading it I often resorted to checking the temp with my left hand on the upper tank.

Hmmmm now that I think about, I’m pretty sure I got the temperature gauge from you years ago. Lol

[Bruce Parker (RIP)]

Originally Posted by Jordan Baker

Hmmmm now that I think about, I’m pretty sure I got the temperature gauge from you years ago. Lol

Warranty expired in 1944...

[Harry Moon]

I learned to drill a small hole in the thermostat to allow some leakage and the release of any trapped air. If you are running a 216 you might try loosening the temperature sender and make sure that there is no trapping air under it.

[Jordan Baker]

Thanks Harry, Ill take a look at that too.


Bruce......dang