water temp

[C Kyte]

Hi,
I recently did a 1500klm trip in E type ans she went good. How ever I notice coolant temp running cooler than normal. I checked for leaks, all good. The car is a 1969 2+2 and been in the family since 1970. I decided to replace voltage stabiliser and coolant sensor on manfold. They were origonal. I put voltage stabiliser in and no difference to temp, still running cooler. I fitted new temp sensor [part number C16895]. I took car for a run and temp needle was in the red on gauge. I got another sensor and tried it and it is almost the same, running vary high on gauge.
I checked engine temp with a lazer thermometer and at senso temp was 68 deg C, at the thermostat temp was 74 edg C, at radiater inlet temp was 69 deg C. So engine temp is quite normal.
I know gauge works on resistence but I dont know if it can be adjusted or is the problem in the quality of sensors, who knows where they are made.
Any one had similar experience.

Chris

[cactusman]

Link to a post all about temp ...I hope

viewtopic.php?f=3&t=10545&hilit=Temperature+sender

Gives resistance at a range of temps...although, unlike the oil pressure sensors the temp senders are not that unreliable....huge over reads suggest a short to ground somewhere between the gauge and sender or a dud voltage reg.

[malcolm]

When you say cool, how cool? My '69 2+2 always runs cool. In normal driving, doesn't go above the "N" of normal, in fact just reaches the start of "N". In heavy traffic, it then gets higher until the fans kick in.

[C Kyte]

My car at normal operating temp the needle sat between N & O on normal. The thermostat is 74 deg and it is a genuine Jaguar thermostat made in UK. The engine is not hot. As I said I replaced voltage stabiliser aswell.
I have an aluminium PWR radiator in the car and it is perfect. The wiring behind the instrument is all origonal, maybe the gauge has gone past its use by date.

Chris

[Series1 Stu]

Hi Chris

It could be that your thermostat is stuck in the open position. That was my immediate thought when you said the reading was lower than usual. I have experienced this before where the car doesn't get up to normal operating temperature due to the coolant circulating through the radiator from cold start up. Another clue is if the air from the heater isn't as warm as usual.

The laser thermometer readings sound a little on the cool side to me. I would have expected temperatures between 70 & 80 degrees C.

Regards

[C Kyte]

I havent taken thermostat out yet, the temp at thermostat is 74Deg C, the thermostat is a 74 Deg one. I do have 2 spare genuine Jaguar thermostats. The radiator is not hot.
Any way I did remove the temp gauge and I tweeque the needle. At normal running temp the needle is in the N/O position on the gauge. The thermo fans cut in when the needle is on the L of the normal on the gauge.

I will see how it goes.

Chris

[C Kyte]

I took thermostat out today and as I guesed it was perfect, not stuck at all.

I took car for a good run yesterday afternoon and temp needle ran between N & O on the normal on gauge. At home I let it idle till the thermofans cut in at L on normal. So I will leave things as they are.
The engine temp was 74 deg at thermostat howsing. Im happy with that.

Thanks for the replies.

Chris