My 12 cyl Series III temp needle runs at the end of the gauge wording and when idling it goes almost halfway to the end line yet the temperature at both the thermostat and against the radiator itself is 180 degrees. VERY disconcerting!Should I consider having the gauge re-calibrated? If so where is a good place for this?

Submitted by dougdwyer1@com… on Sat, 12/21/2013 - 12:47

Which is why Jaguar and so many others eventually went to a gauge that gives a fixed "normal" reading over a wide range of coolant temps :-)

For some, "overheating" is defined as any temp outisde of thermostat control range. For others, "overheating" means outright boil-over.

None of my three Jags has had enough cooling capacity to stay within thermo control range under ALL conditions...city traffic in Las vegas in August, for example. In fact, I'm not sure that *any* car I've owner ever did.

Cheers
DD

Submitted by jerry@moutons.org on Sat, 12/21/2013 - 11:21

This is the real source of the "E-Type overheating" myth. Yes, the car can overheat if the cooling system has not been well-maintained or the engine is out of tune, but "fear of the L" or "fear of 90C" has made many worry as you have. The thermostat is really for keeping the car from underheating when you start cold so the car reaches operating temperature quickest. Normally it will be full open whenever the car is warmed up so it does not in fact regulate operating temperature. Out of the red zone (or not more than 100C) and it's all working OK. If it goes up beyond that, stop and fix it.

Submitted by SE98-32482CJ on Sat, 11/30/2013 - 20:33

J. Patrick from your description the indicator is still in the NORMAL range. That is common and correct. The red area is where you need to be concerned. There were many bulletins issued on this. Jaguar switched to this type of reading as the previous type was also the source of many customer questions although the fact it was in Celsius not F. was a contributing factor.

Submitted by Bfastr@cox.net on Sat, 11/30/2013 - 15:04

You can calibrate your own water temp gauge using info off this link. Its a crude mechanical gauge, but you can get it close.
You will need a variable power supply and a volt meter.
I calibrated mine by putting the sending unit in pot of boiling water, then i wired up the gauge to it using the power supply, and with a digital temp gauge compared the temp of the water to the reading on the gauge and adjusted accordingly.
Granted its only as accurate as the digital gauge, etc, but we arent talking medical grade equipment.

Bob F

http://www.jensenhealey.com/forums/view_topic.php?id=14&forum_id=7

Submitted by Bfastr@cox.net on Sat, 11/30/2013 - 14:58

You can calibrate your own water temp gauge using info off this link. Its a crude mechanical gauge, but you can get it close.
You will need a variable power supply and a volt meter.
I calibrated mine by putting the sending unit in pot of boiling water, then i wired up the gauge to it using the power supply, and with a digital temp gauge compared the temp of the water to the reading on the gauge and adjusted accordingly.
Granted its only as accurate as the digital gauge, etc, but we arent talking medical grade equipment.

Bob F

Submitted by wrischan@yahoo.com on Sat, 11/30/2013 - 12:32

on series 1 there is a voltage converter in the fold down dash that must work properly.
I had to replace mine - the voltage to the instruments needs to be 10v. Higher will cause high temp.

A question - does anyone know the calibration curve for the gauge? It would be nice to have to check it, and the sensor.

Submitted by DavidBarnes71@… on Sat, 11/30/2013 - 11:47

Being the owner of a 68 I am not real familiar with the Series 3's and if the gauges all work the same but my book for the 6 cyl says for fault finding for the temp guage high reading first to check the instrument voltage regulator terminal "I" is at 10 volts. This regulator on my car is about 1 inch X 0.5 inch metal box at the top of the center panel when you flip it down. Next it says to check for shorts in wiring to the transmitter. If you have a XK's Unlimited E-type catalog page E257 has an illustration of what the regulator looks like and calls out p/n 10-BR1307-00 if you find your car has one and might be bad.

I had my tach, speedo, temp., and battery gauges worked at Palo Alto Speedometer 650-323-0243 ten plus years ago and all have been working good since

David Barnes
68 E-Type FHC

Submitted by Pat Mansfield on Sat, 11/30/2013 - 09:50

Already replaced the thermostats, flushed the radiator, and replaced the sending unit . The temp at the thermostat is 180 degrees as it is at the radiator so I know its not running hot. I think I'm gong to get the gauge itself re-calibrated. Anyone know of a good place?