Has anybody retrofitted a coolant system temperature sender and fitted a gauge in the cabin that actually works?

There was a guy on the XK section that made an accessory to force their temp gauge respond without the damping. But I don't know if that ever made it to the later models or would work on the x350.

Most people with the x350 use a bluetooth OBDII dongle and an app. You can get aftermarket temp displays to go with this.

The issue is the cluster programming. The PCM knows exactly what temperature the ECT sensor is reporting, and that data is on the CAN network to the cluster (the cluster is the network gateway for the car as well). But the cluster programming which controls the temp gauge is where the damped response comes from.

There are lots of shops that work on these Visteon clusters, mayone one of them can reprogram these to work the way we would prefer? I don't know if anyone has ever asked.

The gauge is all but useless i m h o.

Autool, 30 some bucks on Ebay. Mounts on dash and plugs into OBDll port. Gives precise temp readings, voltage, codes, fuel trims, O2 readings plus a host of other things, eve color change of readout. Cheap alternative to idiot gauges. Have them on both my Jags.

+1 on the above. I have one on the Jag and one on the Rover.