1. I am not sure exactly where the temperature sensor for the OBD measurement is. It may or may not have good correlation to the radiator coolant inlet. The temperature on my aftermarket gauge display comes from the data provided by the car. It pulls data from the OBD port and displays it. Whether it is right or wrong that is the temperature data the car uses to adjust the fuel to the engine. Since the fuel trims are in range I believe the temperatures being reported.

2. It is possible that the thermostat is not fully opening. Since the car cools fine under load, while moving, I think the thermostat does fully open. My guess is the water pump flow rate is not sufficient at idle to keep it as cool as I would like it. It should not be a problem until the coolant starts boiling somewhere a little over 250 *F. That is probably why Jaguar triggers a warning in the mid 240's.

3. At 10+ years in Arizona I think changing the coolant hoses is a good idea.

I am not going to get too worried about what I am seeing now. I am using those numbers as a baseline and will worry if they deviate very much from the baseline. I got the OBD temperature gauge to serve as an early warning if/when the water pump fails.

Patrick, If you are in Green Valley you should look into the Jag Club of So. Az. - JCSAZ.com There are a few members from Green Valley. We do monthly drives, an annual concourse, and a few other events.

 

1. I believe there is only one engine coolant sensor, and that is located in the black plastic outlet tube. When I recently replaced the outlet tube, the new part came with a new sensor already mounted.

Thanks for the info about the local Jaguar club!

 

Another tidbit. It 76*F in my garage this morning around 11:00am. Outside it was 84*F . I started the car and the WT was 76*F and it rose to 100*F just as the idle went from Open loop to Closed loop (also same time to drop the top) . I put it in reverse and backed out of the garage. It was at 168*F by then. So as I drove out of the driveway it was at 185*F and by the time I was a 1/2 mile away it was at 198*F. Ran at 195*F to 205*F for the next 2 hour drive. Just an FYI

 

Ditto, noticed the same experience on the way home from work via torque. Surprising how quickly the temp sensor gets warmed up but it also helps explain why the cabin heat come to temp quickly. Hoping for the same on frosty mornings.

 

Aren't all of us dumb bells with a 2010 XK or later with no guage and none of the technology here on this forum to measure temperature better for it? Is this not over the top for our "Luxury Cars"? I know this forum is for enthusiasts....But it does take the air out of the balloon for enjoying and owning our fantastic cars to be overly concerned about the engine temp to avoid a blown engine/head gasket etc. Yes?

 

No.

Time has proven that most owners don't know how to correctly interpret coolant temps and frequently don't take the correct action.

The number of instances where the coolant temp has become dangerously high without a gauge reflecting the condition is very small. Instances where a warning is present- but ignored is the real problem.

Oil pressure or battery voltage/amperage indication is not much different.

 

I can somewhat agree as I find you need to temper what is posted on forms. Most auto forms have a tendency to flag individual premature failures as the norm. This causes the sky is falling syndrome on issues that have no substantiate data to support the claims. Water temp seems to be the issue for the XK. We don't have a large enough sample base on this form to either support or not support coolant issues with the 5.0L engines. Just speculation based on a few WP failures and maybe an engine failure due to operator error. So for me the WT gauge issue is more of a curiosity based on having gauges on all of my cars . In fact now that I've been watching and mentally tracking I don't really need to know what the WT is as I know if something goes wrong it will give me fair enough warning. Oh if I tracked the car there are more instruments I would want to see . Enjoy the drive.

 

The analogy is crossing a street when the crosswalk says go without checking for traffic and only worrying when you hear tires squealing.