Water Temperature Gauge Not Working

[DonWheeler]

I own P/2171. It has a Roush 427SR. I've noticed that the water temperature gauge is no longer working. I'm thinking this should be a relatively easy problem to diagnose, but I'm not certain where to start. Any help would be greatly appreciated.
I also have a couple questions.
Does water travel from the manifold through the metallic connection all the way to the water temp gauge?
Will the radiator fan operate if the water temp gauge is not working? In other words, what causes the fan to operate?
Most every thing about this vehicle is new territory for me; thus the reason for asking some basic questions, and asking for help.

Thanks,
Don in Maine

[Alan Watkins]

Originally Posted by DonWheeler

I own P/2171. It has a Roush 427SR. I've noticed that the water temperature gauge is no longer working. I'm thinking this should be a relatively easy problem to diagnose, but I'm not certain where to start. Any help would be greatly appreciated.
I also have a couple questions.
Does water travel from the manifold through the metallic connection all the way to the water temp gauge?
Will the radiator fan operate if the water temp gauge is not working? In other words, what causes the fan to operate?
Most every thing about this vehicle is new territory for me; thus the reason for asking some basic questions, and asking for help.

If you have the standard smiths gauge there's not much to diagnose. It's essentially a once piece thing, the long wire-like appendage and bulb actually being a tube full of ether. If the ether leaks out, the gauge is dead.

It can be repaired though, but you'd want to ask yourself if it doesn't make more sense to put in an electronic gauge, although that's a bit of work as well.

It's funny you should mention this because I know someone else with an SPF GT40 who's water temp gauge died in the first 90 miles of use.

There's no water flowing in that tube. The water heats up the ether at the engine's end, and the resulting increase in pressure expands a bourdon tube in the gauge which moves the needle.

The radiator fan has its own thermostat on the upper left corner of the radiator, so it's not affected.

[Jack Houpe]

Wait till your oil pressure quits when your doing about 80 mph. It's a good check for your heart.

[DaveM]

Originally Posted by P2164

Wait till your oil pressure quits when your doing about 80 mph. It's a good check for your heart.

Sounds interesting Jack! Did the plastic tubing break or was it the gauge?

[Jack Houpe]

Originally Posted by SwiftDB4

Sounds interesting Jack! Did the plastic tubing break or was it the gauge?

No the tubing was fine, I drove the car to Mike Trusty (fellow spf gt40 owner) in Little Rock AR which is about 4 hours from my house, on the way there the pressure started to drop, it got down to just above 0 and my heart was about to pound out of my chest but the motor sounded good and my accusump light didn't come on in the dash (comes on at 35 psi) so I pulled over and looked at everything and the gauge on the back of the accusump said 50 psi. I got to Mikes and we checked it again and it was fine but the gauge on the dash was still low. I took the dash gauge out and when I looked at the little hole for the pressure inlet, it had a piece of crap plugging it. I noticed it had been leaking around the nut so decided to just replace all of the gauges with electronic gauges from speed hut. They are nice and bright at night.