Hi all. I have a 2003 X308 Vanden Plas which I absolutely love. Yesterday I took it for a long ride (Great weather in Maryland USA) and noticed the cooling fan was constantly on even when I stopped for Gas/petrol which was unusual. I also noticed the temp gauge would go up almost to the red light mark and then come down and up again in an erratic manner. I did also smell some coolant. I stopped to let it cool off thinking maybe a gremlin as these cars do have most times. I drove home and the same symptoms. Car was driving great by the way with no hesitation on pick-up. I'm thinking maybe thermostat, housing, water pump, or head gasket? I need some help here. In the meantime I'm not driving her until I get this sorted😊

 

I think all of those items would be good to change (save for headgasket of course) if they haven't been done. That said, the erratic nature of the temps seems to indicate a potential thermostat that is funky. The in dash gauge is horribly buffered, so I recommend you buy an ELM obd plug and monitor your temps real time with OBD Fusion (free app).

Given the cost, I'd do the pump, thermostat and housing with some fresh coolant and then monitor your temps closely.

 

Thanks for the advice. I'll start with those and see how it goes👍

 

Check out this gadget from one of the XK members. I put one in a few years ago because I live in a high altitude area and the ECT starts going up rapidly when I'm going up the hills. The gauge is spot on now and squeals when you hit 236F, so I know it's time to stop the aggressive driving. 244F is the number to avoid a possible blown head gasket.

https://www.thejagwrangler.com/xk8--...realgauge.html

Good luck with your current issue.

 

Mike- also change the outlet pipe AJ85885. They do eventually crumble allowing the hose to blow off, and they come with a new temp. sender.

 

Be very careful around black hard plastic coolant lines. They can break by looking at them.

 

The key is to know the exact engine temperature: real time readings from the OBD would provide this. If it is overheating, Then change the front end cooling parts; since the labor is the same for any one, may as well do them all: belt, maybe belt tensioner too, water pump (I like AC Delco), stubby pipe, cross over pipe with temperature sensor, thermostat and thermostat tower, refresh coolant, and check the hoses. There are lots of threads on each of these subjects in addition to YouTube videos. If you are going to do this work yourself (a full day's job) read everything you can. Or find a really good independent (lots of dealers will no longer work on these old guys: mine won't).

Sometimes the fan switches go bad: do a search. Check for foaming at the oil fill and dipstick (head gasket). Let us know.

And to reiterate #6: be super careful around those black plastic hoses . . . truly fragile

 

Thanks for this. Super helpful!

 

on the coolant tank there are two plastic hoses that connect on the front of the tank. The lower one goes to the radiator top; the lower goes to the overflow tank. If you reverse them, the car will spew out coolant. Easily swapped in the wrong positions! Know be experience.
I'd guess by you description the thermostat is faulty.
Also, the plastic water manifold that the temp sensor screws into has a tendency to rot out. When you remove the part, check where it connects, especially near the large hose. If it looks worn thin or soft, you might want to change that while in there. (It's made of something akin to bake lite.) Usually then develop a crack somewhere and sometimes they pop a hole. I've changed them on all four of my cars past and present.

 

So what happens to the higher one?

 

I had to read that twice but I know what David means, it's a classic mistake we've all probably made.

 

How it should look. Keep in mind this is a S/C car but, the premise is the same.

 

Thanks 😊👌

 

Thanks for the info - super helpful!👍

 

I meant the upper one goes to the overflow tank! Doh!