Lack of temperature readings after rebuild

[the moosehunter]

After what seems like a successful engine rebuild, my temperature gauge has decided not to show me any readings at all

I thought this could be down to an air lock, but it's been through half a dozen warm up cool down cycles now and about 50 miles and it still won't budge off the stop.

Just wondering if the sensor actually sits in the coolant or whether its just reading the temperature of the manifold around it. If so could be holding out for no reason.

All seems well under the bonnet apart from that. Heater pipes warm, top hose warm, bottom hose cooler.

Checked the voltage at the supply wire, and it's reading 6.4V

Will check the resistance later today once it's cooled down a bit. (Gonna have to find a passing child to get his hands behind the distributor, as I struggle with my sausage fingers)

Any hints all you sparky's

Have found on a search about using the "spare" bullet topped sender. May have to go this route if I can't solve the mystery.

Seems a bit coincidental that it's failed at the same time I've taken everthing apart. Couldn't possibly be anything I've done....could it ?

99% happy Moose

[jonnyb]

The sender does sit in the coolant. Only the front of the inlet manifold has coolant in it. My advise would be to check the volatge coming into the back of the gauge, if this changes with the temp on the car then the gauge has gone (or the earth), if not then its the sender. It could of course be both.

[captiv8ed]

I had exactly the opposite to this after fitting my cam. Mine went off the scale within seconds of firing it up. If you short your wire to earth, you should get full deflection on the guage (+130 degs). Instead of changing the sensor, you can use the unused Landy one that sits on the N/S front of the inlet, the round one. All you need is a variable 200 ohm resistor (a shocking 31p from maplins) and you're on. Adjust the resitor so ther guage reads 87 degs just as your fans cut in and you know it's reading right. According to info on PH, this sender is far more accurate than t'other, as it has better flow around it and isn't in the flow of coling air. I can post a pic if you want.

[The Moosehunter]

Cheers Captiv

Earthed out the gauge and yes it does deflect to the max

Set up a link wire from the sender inside the car so I can see what resistance I'm getting on the origonal sender as the car warms up (without the need for 12" fingers)

Gonna get myself a resistor today, and will go the alternative route as I'm getting pretty hacked off with it

Moose

[normalbloke]

captiv8ed said:

I had exactly the opposite to this after fitting my cam. Mine went off the scale within seconds of firing it up. If you short your wire to earth, you should get full deflection on the guage (+130 degs). Instead of changing the sensor, you can use the unused Landy one that sits on the N/S front of the inlet, the round one. All you need is a variable 200 ohm resistor (a shocking 31p from maplins) and you're on. Adjust the resitor so ther guage reads 87 degs just as your fans cut in and you know it's reading right. According to info on PH, this sender is far more accurate than t'other, as it has better flow around it and isn't in the flow of coling air. I can post a pic if you want.

That's working on the assumption the fan stat hasn't been changed to another temp?
Or is the fan ECU driven?