Hello All

I have a bit of an issue with my 1999 XK8 and would very much appreciate some guidance.

I bought the car a few months ago very cheaply, with some known issues. Namely the 'restricted performance' warning apparently diagnosed to a cat-converter. I took the car to my trusted mechanic (of some 20 years) and he said actually both cats were shot, he took them off and showed me bits falling out of them, they also rattled like hell when they were on the car.

Unfortunately a day or so later the warning light came back on, so back to the garage, this time for some 'upstream O2' sensors .. This still hasnt worked. At the same time i was getting a red light warning saying ' coolant low'. on checking the coolant is absolutely fine, so a sensor was removed and cleaned, and put back in, this fault stopped for a good few weeks. in fact, both warnings had stopped, until the weekend, when both came back. Coolant is fine so im guessing the sensor will need replacing, but the restricted performance thing is a different matter.

Whilst i expected to have to spend some money, and am happy to do so given the overall condition of the car, i would like to get this fixed in the least painful manner. So i wonder if i should take the car to Jaguar (like wheeler dealers ! ), or a specialist and get a diagnostic done - will they have different / better diagnostic tools than my mechanic ?? then hand the diagnostic over to him to do the work maybe.

At the last visit to my mechanic he mentioned that if we still get problems he would get a 'jaguar' guy in to take a look. so thats an option..

would appreciate any other thoughts though..

all the best
Danny

 

Read the codes. Most generic code readers will suffice, doesn't your mechanic have one?

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They did not catch the 02 sensors when they did the cats? Usually for cats to go bad the 02 could be close behind for the reason the cats went, not always, but I thought they kinda went hand in hand.
Low coolant would be the sensor in the reservoir and not the one at the Tstat. I would replace the whole take which will come with the sensor. Eventually you will have to replace that tank so you may as well now. 120 bucks and a easy job to do yourself. When you check the coolant, is the fluid right at the bottom of the opening of the tank, if it is lower it does not take much to make that light go on.
Pull codes also if you have not.

 

If you have a droid phone you cant dowload the Torque App for like 5 bucks then buy the ELM bluetooth adapter from EBAY then you will always have your own OBDII reader for ANY car you own with obdii

 

There are MANY just looking at the list and guessing 60-80 codes that might cause a restricted performance, and they are all over the chart in what might be wrong. Guys above are correct either get a reader or go somewhere when the light is on and have them read and post here. Folks here will then be able to help narrow down where you should proceed.

 

I also have a 1999 XK8. I do not know about the cats as I have not had that issue (yet), but I have had the low coolant warning. I would get the warning, check the level and the reservoir would be full. Reading on this forum that they are prone to warnings even if they were just slightly low, I'd "squeeze" in a little water in the reservoir and all would be fine for a couple days...then the warning would return. So I filled it up at the thermostat (I was convinced it would break for some reason even though it's aluminum...) all good, then the warning again. THEN...I noticed the upper radiator hose. The clamp was loose enough to let coolant out under pressure, but not loose enough to slip over the fitting lip on the radiator. I tightened it, topped off the coolant level. That was 1 1/2 years ago and the low coolant warning has never returned.

 

I hade the same issue with a hose clamp, it was not on right and would let a little fluid out but not empty the system. If you put on new hoses as i did i would go back and recheck them a few times after a few drive cycles. If you get the clamp put on an angle, just a hair, it is not round to the house and tstat housing, LEAK will happen.

 

Had the same message (restricted performance) show on my '03 S Type V8. 62,000 miles. There was no difference in the actual performance. Took it in to the Jag dealer, they checked it all out and found the computer code showed that it was in relation to an injector bank, but when they checked it all out, said nothing was wrong. They feel it might have been a computer glitch, rather than an actual mechanical problem. They reset the computer and everything seems fine since. They never charged me anything for the service.