Hi,

I have a 2003 XJ8, just bought it yesterday.. It is overheating whenever I drive uphill in long runs, also while driving it home on the Interstate.

Any ideas of what this problem might be? It does not lose coolant.

Thanks in advance

 

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If you are saying the temperature gauge is indicating overheating you are very close to losing the engine. It's a glorified idiot light and doesn't move from center until about 230 deg. Stop driving until the problem is resolved.


It's possible the thermostat is not opening, the water pump vanes have failed, or the radiator is plugged because someone added the wrong coolant.


Get a code reader that will read temp. through the OBD port and check the actual temp. There are adapters that will work with a smart phone as well as stand alone readers.

 

Thank you for the prompt reply, @RJ237. Would this adapter work? It seems to good to be true.
https://www.ebay.com/itm/Mini-ELM327...-/232379432550

 

Welcome to the forum theo90,

Take the warning about overheating a Jaguar V8 engine VERY seriously. It is an engine killer.

Graham

 

hi Graham,

Thanks for your reply! Took the car to a mechanic, and although he is not specialized in foreign cars (specifically Jaguar),he confirmed the engine was running at only 160F, so not very hot. He suggested the gauge may be faulty.
Taking car now to a foreign shop to check more on this...thanks

 

Not common, but could be the sensor.

 

Hello all,
New to posting here but have used this resource for years. I didn't start a new thread only because it's very similar to the original poster. 2003 XJ8 VDP is now having a overheating issue as of today. Started running hotter in city traffic traffic with AC on and I could hear the fans running. I had to make a stop so I figured I'd let it cool off while I run my errand. Fans were still running when I shut it off at high speed for about 2 minutes which is out of the norm for this car since I've had it. Came back about 20 minutes later, temp gauge was still at the halfway point before I started it. Proceeded to drive in city traffic when the temp started to climb. Got to my next stop just as it hit the high mark and the light came on and the engine went into "limp" mode. Shut it off and checked under the hood, no coolant leaks found (yet), radiator hoses hot and slightly swollen. Fans still running at high speed. Waited awhile for it to cool then checked the coolant level in the resevoir. A little low but I believe that was because as I was loosening it, coolant went to the overflow tank and leaked from there. I left it to cool again then came back about another 30 minutes and started to drive home. Took the precaution of staying off the highway as it was still running above normal temp and spiked twice (pulled over, shut it off) during a 20 mile drive. Prior repair history for the cooling system was replacing theT-stat and water distribution pipe (cracked). It was winter time when it steamed over but did not overheat and that was around 40k miles ago. I want to properly diagnose this before throwing money at it which will probably happen anyway.

 

If you replaced the thermostat 40K mi ago I would start there, it's not expensive and they do tend to fail in the closed position. At least put it in a pan of water and heat to boiling to see if it opens fully.

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Finally got around to replacing the thermostat. I confirmed that it failed by placing it in a pot of boiling water. Five minutes in and it refused to open. I suffered a couple of minor mishaps along the way of replacing it. One of the bolts broke off for the water distribution pipe. Lucky for me that enough of it was left to twist out with vise grips. Losing a bolt for the thermostat housing was another. It's still somewhere behind the headlights but couldn't find it. Put it the new one, went and picked up some replacement bolts and put it all back together. Filled with coolant and burped the air out then the test drive. I let it idle first to check for leaks then drove it a few miles. No issues, temp normal. Came back home and checked for leaks again then took it on the highway, no temp issues at all.