Bad Temp Sender Gauge on my 1500 ?

[datsun65]

On my 1500 the temp gauge doesn't work when the cars is running.

Now, unlike the 1600, on the positive ground 1500 when the gauge is grounded out it drops down to the bottom (ie, Cold) as it is suppose to. Ungrounded, the gauge reads at the top (ie, Hot) position.

Now, when I turn on the ignition, the temp needles settles from the top range, to the bottom range (as it supposed to do). However, as the car warms up the needle never rises..

I think I may have a bad sender, but wanted to solicit feedback...

To replace the sender , what is the easiest way to actually removed the retaining nut? Is a socket wrench used. Once the retaining nut is removed, does the sender easily come out...or is it a chore?

Thanks for the input & suggestions

[spl310]

Dan,

The sender may not be bad. They are brass and the head is iron with a steel gland nut holding it all together. Sometimes they come out OK, sometimes you shear off the top of the gland nut. I have had to use a dremel tool to get one out in the past (1600, but the idea is the same).

I would strongly recommend using a 6 point socket and lots of penetrating oil.

I have a 1500 head on the shelf that has had the nut removed, but the sender is not coming out! It will have to be either hammered or drilled out. Not a fun proposition - especially if you slip and screw up the head!
Best of luck!

[datsun65]

The sender may not be bad

Sid,

Do you think it is a bad sender? Or is the sender Okay?

Thanks,

Dan

[spl310]

The senders are blamed for all the ills of the world sometimes when it is just a matter of corrosion. Still, once you have it out, it does make sense to just put a new one in the hole if they are available for a reasonable price. I think that you should pull it and try another one.

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[datsun65]

Mark...Great idea.

Dan

[itsa68]

If you have a multimeter, could you test the resistance between the sender contact (with the wire removed) and the retaining nut as the engine warms up?

It might show if something is wrong without having to remove the sender.

Ray B.

[dbrick]

You could check resistance from the nut to the sender body and to batt ground (+?).

Could you also just clip a jumper from ground to the sensor body?

I understand that strong vinegar (and a bit of Virgin olive oil, maybe a touch of oregeno if you like ) will help loosen brass/iron/aluminum corrosion. You can soak a rag and leave it wrapped ariound the fitting Good mag wheel cleaner has been known to help too.

A bit of antisieze or dielectric compound on reassembly will help avoid some corrosion later.

[datsun65]

I already have a new temp sender, so I'm going to try the new sending unit in boiling water and see if the gauge works...If it does, then I step through the process removing and replacing the sender..

I just looks like it will be a major pain to r/r.....

[67 1/2 1600]

I could barely squeeze my butterfingers between the heater hose ontop of the sender and the exhaust manifold. Good luck!

[dbrick]

If it really won't budge, Could you just abandon the old one and put the sensor somewhere else, like the thermostat housing or the intake manifold water passage?