Coolant Temperature Sensor 1977 XJC 4.2
 

When the engine is up to operating temperature (assumed!) the temperature gauge continuously reads half way between zero and the N on "normal". This is the case, even after a long run.

I have blanked the radiator with some cardboard to see if I can bring the temperature up, but nothing changes. The heater blows warm air so the engine is warming up, but to what extent I can't tell.. I want to start by replacing the coolant temperature sensor and, if that doesn't work, address the gauge itself and finally the thermostat.

Can someone tell me where the sensor is on the series 2 4.2? I can't find any reference to it anywhere. If anyone else has experienced a similar issue, I'd be interested to know.

I've completely revamped by 4.2 XJC S2 with two electric fans (eliminating the viscious fan) and installed and temp sensor in the upper radiator hose. So I can't answer your direct question. But what I will say is the you might want to invest in a small money digital temperature laser gun from HF. That way you'll really know what the correct temps are anywhere on the engine. Also great for shooting frying pans to see when they are ready for eggs. Want to try something really cool with the temp gun - shoot the sky and then the clouds - REALLY A EYE OPENER the temperature difference. I also use my for A/C air in versus air out. You'll find all kinds of uses for it.

Thanks
!!!! I have one. going to play a bit more
Carl

My experience after being a Yacht Broker and being on over 600 surveys in the past 17 years is that analog gauges are notoriously wrong. And that digital gauges (or at least Surveyors digital gauges) are MUCH more accurate.

Anyone on this forum ever hear of phone cameras ? Just curious !

Yes, in fact I have had two or three over the years. They seem to be quite handy and some people make them a necessity in their daily life. If you are interested in trying one, most internet providers will carry them as well as cellular specific providers which are commonly advertised. There are many styles and features to choose from and the monthly charge is not that bad.

I hope this helps if you're thinking of buying one.........or maybe you were just making a snide remark because someone didn't include a picture with their post. Either way, good luck with your pictures.

Dave

Nose,
the sensor is usually up under the inlet side manifold above the dissy/ if you ground the wire out the temp gauge it should go to full high, if that happens then you know both are working, how hot to touch are the heater hoses at the back of the motor? & the top radiator hose at the thermostat?, what cooling fan system are you using...viscos or electric fans?....are you just curious about what the real temp is of the motor?

Coolant Temp Gauge
 

It was a snide remark. I try to post photos with verbal replies. In this case it would help if someone just posted pic of the gauge sensor location.

Fair enough.

Dave

....i'm wondering where the photo's are to go with the snide remark........ :icon_cool:

Photos
 

If I could find the damn gauge sensor, I'd be glad to post one. Why is it so hard to get a straight forward response on this forum ?

I believe this is it.
https://cimg9.ibsrv.net/gimg/www.jag...a9a5c7a9e6.jpg

Coolant Gauge Temp Sensor
 

Makes sense. Green single wire .
Thanks !