Hey guys I'm new here to Jaguar Forums and I was wondering if you guys could help?
So, currently I own a 2000 Jaguar xj8 vanden plas. And I've owned the car for over a year. At first it wasn't a problem till now. By once the jag hit 98,000 miles on the clock. I sent it to a very handy mechanic of ours for a oil change and a coolant refill. But before I sent the jag to the mechanic I checked the oil level and it was below minimum, it really need the oil change bad. And second was the coolant refill because the check engine light was on, and said the "engine coolant low". So I took it to the mechanic and had the services done. But about two days later I go pick the jag up and start heading home. And I made it home. But I came back to move the car to the back of the house were we park most of our cars. And I started it up like normal and I sat there for a good four to five minutes and suddenly the temperature gauge went to the top and the little red light came on. "And yes the car felt a little more warmer then usual and the cooling fan was on full" So I turned off the car and just left it there because i really didn't know what to do. So the next day. Down the street their is a friend of my dad who is a mechanic. And I asked if he could check and see what's wrong with the jag. So he came over and told me to start the car and just let it run, to see what it would do. And sooner "like four to five minutes" the car started again to overheat. So this mechanic told me it MIGHT be the thermostat that might be at fault. So fastfowerd to the weekend. I go to an auto zone and find the thermostat I need and a new bottle of coolant. The mechanic was able to replace the thermostat but to note that the thermostat was really dirty and also in the housing. But either way he cleared out most of the gunk "the gunk was noted to be a light orange which Is strange because it uses green coolant" and replace the thermostat. But not the end of the story yet so I drove I around and the first stop was good I turned off the engine and checked it. But I did notice a faint small of burnt or something. But I turned I on and started my next little test and six ish minutes into the drive the temperature when up just a little then down. "Note my speed was ranging 25 to 40 mph. So good so far it was untill when I was going back home I started to go a little over 40 almost at 50 mph was when the temperature rose all the way up and the little red light turned red. So I turned off the car and a minute later i turn the car back on the the temperature stayed in the middle. And I actually made it home. And now fastfowerd to today 11/8 it's been a little more the one week since I turned the jag on so I turned I on once every thing was good then I turned it on again, and then another time. And on the third time about a few minutes in the start I turned on the a/c and about a minutes later i hear a huge crash. And on the temperature gauge went all the was down and the red break light came on. So I turned the car off quickly and by then I've open the hood and didn't notice any the different. I tried I one more time and I worked as usually but I did have the a/c off this time.
So that's the jags story if you guys can help in any way, thanks. But if you guys have any questions I'll try to answer asap. And any suggestions are greatly appreciated. Thank you for your time.

 

It is a bit hard to read through your posting, but I think you should first concentrate on the following:

1. The gunk you already removed: I presume they mixed coolant types, and now you have the mess. It is not limited to the thermostat area, but probably everywhere.
You will need the system and all its components properly flushed, or whatever is needed to get it out,

2. The waterpump: as a result of the above, the proper functioning of the waterpump is questionable, and you should check / replace in the same time,

If you further invest a little in a OBD2 reader, and install a free program on your phone, you will be able to read engine temperatures in real time.
The car gauge is absolutely useless, and basically only warns if it is almost too late.

 

I would agree with the coolant contamination, you need to flush the system a few times to ensure that you have clean water running through.

 

These engines take the orange coolant, mixing coolant types leads to sludge. You will need an engine coolant flush, a bit like a liquid drain unblocker that can be found at any auto parts store, drop the coolant and follow the instructions, the coolant system may need more than one flush, but as others have said this is your main problem to attend to.

 

2000MY onward were filled with the Orange Colored Coolant from the factory as Sean B stated. The late 1999MY cars were filled with the Extended Life coolant as well (Check your VIN).

bob

 

I don't understand this "I heard a huge crash!" Where, why, when, how?

Is the oil level correct? Has the water pump been upgrade? Are all the hoses tight? Does this engine run correctly at all speeds?

Are the two overflow hoses crossed or parallel? My choice! They need to be crossed.

 

I fell into this thread because I had a question on coolant and I got it sort of answered. A thought on post style.

• You want your post to be easy to understand both to get the proper help and to leave a record that may assist others in the future.
• Stick to the facts that matter. That the guy who lives across the street is a friend of your dad may be a fact, but it does not matter.
• Observe the chronological order (but before I did this, I did that)

Thanks