Temp. Gauge not moving

[racerx]

Hello, have not been here for a long time and just noticed that my 71 Datsun 510, temp. Gauge, its mechanical, is not moving. It's by the "C" cold, I ran it for over 10 minutes and needle does not move. Both top and bottom radiator hose is warm. Any suggestions is good. I'm thinking its the tstat and stucked open.

[carterb]

Check that the connection to the sending unit is not corroded and preventing the electrical contact.

[thisismatt]

Ground the sender wire and see if it moves.

[racerx]

Its mechanical not electric 

[thisismatt]

My mistake. Throw it in the trash and get a new one?  Should be warmed up after 10 minutes, even if tstat is stuck.

[datzenmike]

1 hour ago, racerx said:

 . Gauge, its mechanical

 

I don't think so. It's run by electricity.

 

Go to the thermostat housing and on the front below the top rad hose is the sender with a Yellow/White stripe wire on it. Carefully pull it off and touch it to the thermostat housing, grounding it. With the ignition on the gauge should rise all the way to the top of the HOT range.

 

If the gauge does now read the sender is bad OR the connection is bad. Clean the sender and wire terminals.

If the gauge still does not move the problem is towards the gauge or the gauge. Is the gas gauge working? they are both on the same voltage regulator and fuse.

 

[racerx]

Its mechanical...I took out the brass looking sender unit, looks like a bullet,  and, hit it a couple of times with my wrench and cleaned it out. It was corroded somehow...then had my son light it with a lighter and moved...I I think it's fixed. Thanks to all.

[datzenmike]

I'm saying there's no mechanical connection between the gauge and the hot water. It's electrically connected and run.

[thisismatt]

Mike, there are mechanical temp gauges.

[datzenmike]

But this isn't one of them is it.

 

How does a mechanical temp gauge work? Like an oil pressure gauge on a tube?

 

[thisismatt]

He said it was, and reiterated again.

 

Yes, a sealed tube

[racerx]

Like a capillary tube, actually looks like a bullet, maybe 2 inches long. It senses the water temp. And is located inside the thermostat housing.  The other end is connected to the temp. Gauge. I heard that ether is inside from ol skool mechanics. Never took one  apart. But it's working now. Thanks. 

[datzenmike]

30 minutes ago, thisismatt said:

He said it was, and reiterated again.

 

Yes, a sealed tube

 

Just saying that owners are often new and mistaken about what they have. (but not in this case)