A little Disco help

[eflatlander]

97 Discovery SD 160000 miles new head gaskets at 153000,temp gauge will go to hot and then drop back down. Changed out both temp sensors and the thermostat just got back from test drive gauge went to hot and stayed there. I got home and with the engine running shut off the head lights and the temp. dropped back to normal??
Thanks for any help!
Eric

 

[dvsjw]

Guess!: If everything else is good might be trapped air. I am not a disco expert... This has happened to me with two vehicles. Check the reserve hose, might be damaged/open.

 

[roverandom]

The gauge reads resistance from the sensor. IIRC the lower the resistance the higher the reading. You have a situation where there is a short to ground giving you a false reading. It would seem the lighting circuit has something to do with it, I would start looking for shorts in the sensor harness.


Sent from my iPhone using Tapatalk

 

[eflatlander]

I will look at the harness in the AM thanks for the info.

 

[evilfij]

Check the ground. On a d90 that would be the most likely cause.