Hi guys, I have a 2003 X Type I recently got with only 53,000miles, I live the car and it’s a one owner straight to me, I have a coolant light on, temperature is good and steady and there’s plenty of coolant, I replaced the radiator and the condenser but filled up the system completely. I couldn’t find this sensor anywhere, please help! Also do I need to bleed off air from the system as I couldn’t see any bleed off valve. Thanks in advance!

 

MIke, I seem to remember that the coolant temp sensor is on the left side of the engine (as you are looking at it from the front bumper), tucked down by the IMT valves (those black round disks on the side of the intake). It has been a few years since I have had my X-Type and don't recall exactly where the sensor is. Looking at pictures in the service manual, if you look where I say, you will see 2 silver tubes coming up to the top of the engine. These are the fuel rails. On the rail nearest you, there will be a metal block in this line with a sensor coming off of it. This is the fuel temp sensor. If you look just to the right of that, you should see a sensor pointing straight up at you. That is the engine coolant temp (ECT) sensor. Disconnect the plug, then you can remove the sensor (may get some coolant to come out, so, may want to drain out a bit of coolant first). Hearing that this sensor has failed is not a big shock to me. A few members here have had this same issue. Make sure to put on some sealant to make sure the sensor gets a good seal. Hate to see you create a minor leak.

Now, for bleeding the coolant system. Jaguar has a special procedure to do it and it involves crimping closed the line going back to the dash heat exchanger. Most have found that you can get the same bleed by simply letting the car run on its own. If you look at the overflow bottle, there is a line that comes out the back(top) of the bottle and runs to on top of the engine. This is the self bleed line. As you run the engine, a finite amount of coolant runs through this line and it pulls the air out of the engine. So, to fill and vent the engine, you simply fill the overflow bottle up (take it to slightly above full), start the engine and let it idle for about 5 minutes or so (let it get up to temp). During this time, you will see air bubbles in the expansion tank. If the level drops to the low line, add some more coolant (keep the cap off of the expansion bottle). Once at temp, you can rev the engine up to say 3,000 RPM and hold it there for 10-15 seconds. This will help push any bubbles that may be left around and back to the expansion bottle. Once you think you have very few bubbles coming out, turn off the engine and rest the cap on top of the coolant bottle. Let the engine cool. Top up the coolant bottle and then install the cap. In 50 miles or so, you may need to do one final top off, but that should be very minimal fluid. The big thing is not installing the cap with the engine hot and not opening up the expansion tank later to allow the tank to reach atmospheric pressure with the engine cold. The cooling system works best if it is under a slight pressure when the engine is up at temp. Just be careful with the expansion bottle as that little line coming off the back/top is easy to break off and then you have a real mess on your hands.