Quick question on temp sensor wire colour

[Claude]

Spent the day sorting the 411-s1. Quick question:

Can someone go out to their V8 Bristol and have a look at the temperature sensor wire to see what colour the wire going to the sensor on the engine is (near the distributor). It should either be green or yellow. Right now, the wire going to my sensor is green. My temp gauge is showing a rapid rise to red, but it is uncertain if this really is an overheating engine or bad information being sent to the gauge. Before I tear into it, I want to make sure that the last person who touched my motor did not reverse some wires.

I have some of the wiring diagrams, but not one for the temp sensor and gauge. If someone has posted that on the web, let me know.

Latest development on the car... removed the petrol tank, dumped half a bucket of gone-off fuel, leak tested it, and then reinstalled. Car now running on a proper fuel tank instead of a plastic 5 litre one strapped in the spare tyre bay. Noticed the sway bars attached to the rear diff were not bolted on. Wonder what else has been left undone.

Appreciate a reply on the wire colour, and also, please indicate your model, in case some are different from my 411-S1

Claude

[Kevin H]

Claude,

It's on this site;
Resources - Bristol Cars - Owners and Enthusiasts Forum

Kevin

[RGSchmitt]

Claude -

I had "chronic overheating" on my Alfa 5 years ago after a rebuild
and, fortunately before any serious disassembly, replaced the temp
sensor on the block. "Normal" temp returned. Any part of the
circuit - gauge, wiring, sensor - could be faulty.

It's much easier to confirm engine temperatures with a new sensor and
separate gauge before removing radiator etc. Or perhaps an infrared
gun, if one knew what "normal" should be.

Bob

[Claude]

Thanks Kevin and Bob,

Having the wiring diagrams on line is a wonderful resource. Is there a way to put keywords on the files so that a google search on "Bristol 411 wiring" would come up?

Looks like the right wire is hooked to the sender. So next I have to rummage in my old stock to see if I have a temperature gauge from an Alfa, G-wagon or some other old car to test. These are times when I do miss being in the USA where I would just pop down to the parts store and buy a sending unit.

Claude

[MTH 411]

Another point to remember is that the instruments often have a separate voltage regulator which should give 10.5 volts to avoid variations in readings when there is a large load on the battery. This may also be faulty so when you are running the temperature gauge will read high as the voltage will be too high (14.5 V). It was an issue on my 411.

Mike