What should the tempriture gauge read on a 3.4 XJ6 engine ?
I have one in my MK2 gauge is around 70 , think that’s a bit low , may need a new sensor !
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All xk engines are meant to run at the same temperature, Ian…
Low temps usually means a faulty thermostat - it’s sole purpose is to keep the engine hot. An infrared thermometer will tell real engine temps, and measured at the sensor; revealing if a low reading is a gauge/sensor problem…
Frank
xj6 85 Sov Europe (UK/NZ)
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Thank’s Frank , I thought as much , I know the Gauge is good , and I know the Sensor is good on the old Engine , do not know the history of the Sensor in the XJ6 Engine , so I have just changed the Sensors over , and see what happens !
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Putting in a verified good sensor may clarify the issue, Ian, but put the suspect senor on the other engine, as a double check.
Reputedly, two different gauges were used over time - requiring different sensors. I still suggest you get an infrared thermometer - it’s a very useful tool…
Frank
xj6 85 Sov Europe (UK/NZ)
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The other engine is out the car now , the sensor come with the XJ6 manifold , Gauge is in the MK2 , so may be a miss match , all MK2 now !
Infrared thermometer on order 
So what temp do we agree is
I did put the old sensor back in and temp was around 90 , going up to 100 at lights and the like
So then got a new sensor , add said for MK2 and XJ6 , temp on the gauge is back to 70 !
Yet to test temp with Infrared thermometer !
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Indeed, Ian - if the temp is really 70; you are running too cool…
Apart from a possible mismatch of gauges; the temp readings depends on the placing of the thermostat and the sensor. The ‘standard’ intended running temp of engines themselves is around 85 - 90C, but that can be obtained in various ways…
Frank
xj6 85 Sov Euope (UK/NZ)
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