Jaguar Temp Gauge Issues Signal Cooling System Problems

I had a very similar issue with my 2007 Jaguar XJ Diesel last winter. Having some experience with basic car maintenance, I initially thought it was a major automotive cooling system problem, but it turned out to be much simpler. The symptoms matched yours exactly, inconsistent temperature readings, prolonged warm-up times, and check engine light. After taking it to the workshop, they discovered a blown fuse connected to the temperature sensor circuit. The fix was straightforward, they replaced the faulty fuse and performed a diagnostic check to ensure there were no underlying issues causing the fuse failure. Total cost was 52€, including the diagnostic scan. Before suggesting this might be your exact issue, it would help to know: Have you noticed any coolant leaks? Does the radiator blockage warning ever appear? When was your last cooling system maintenance performed? Are there any other warning lights besides the check engine light? These details would help determine if your issue is similar or if you might be dealing with a different problem in your cooling system.

The engine overheating symptoms turned out to be less serious than expected in my case. Last service was done at 75000 KM and included a cooling system flush. After closer inspection, the root cause was a partially clogged radiator creating restricted airflow. The debris buildup was preventing proper engine cooling and causing those erratic temperature readings. The repair involved: Deep cleaning of radiator fins, Coolant system pressure test, ECU diagnostic scan, Thermostat replacement as preventive measure Total repair cost came to 320€. The car now warms up normally and maintains stable operating temperature. Definitely worth checking the radiator condition before assuming more complex issues. Worth noting that regular cooling system maintenance could have prevented this. Planning to have the radiator cleaned every 20000 KM going forward.

I can relate to your radiator blockage discovery. After fixing my initial fuse problem, I actually encountered a similar radiator clogging situation about 6 months later. The thermal management problems you described with the clogged radiator match what I eventually experienced, inconsistent temperature readings and poor warm-up performance. My repair cost was slightly higher at 380€ since I also needed the cooling fan relay replaced. Really good point about preventive maintenance. Since my radiator service, I've made radiator cleaning part of my regular maintenance schedule too. The engine cooling performance has been much more consistent. A tip for others reading, leaves and debris can cause serious radiator blockage over time. A visual inspection of the radiator fins during routine service can catch these issues before they affect engine cooling performance. Glad you got it sorted with a thorough cleaning rather than needing a full radiator replacement. The thermostat replacement was smart preventive maintenance while they had the cooling system opened up.

Thanks for the follow-up on my radiator situation. Your fuse experience shows how thermal management issues can have multiple causes. The restricted airflow in my case definitely created more problems than expected. After living with the repairs for a few weeks, the improvement in engine cooling is really noticeable. The temperature gauge stays rock steady now and warm-up time is back to normal. Such a relief it was just radiator blockage and not something more serious. The mechanic showed me the buildup they cleaned out, quite shocking how much debris had accumulated in the cooling grille and radiator fins. Makes total sense why the engine was struggling to maintain proper temperature. For anyone reading with similar symptoms, my total repair bill of 320€ included: Radiator deep clean, System pressure test, ECU diagnostics, New thermostat The preventive thermostat replacement has proved worthwhile. Engine runs smoother overall now that the cooling system is working properly. Adding radiator inspection to my 20000 KM service intervals going forward. Still cheaper than what I feared when the problems first started. Good reminder that regular maintenance prevents bigger issues down the line.