Have had my 2007 XK conv since it had 15K miles and it now has 67K. Dealer serviced and I've also done some of my own work on the car like replacing front rotors, pads and the thermostat.


I replaced the thermostat over a year ago as it was popping out P codes as the rubber seal around the thermo had failed and it wasn't allowing the engine block to get up to temp before opening (was still in one piece so nothing had fallen into the block).


A couple of months ago I was in slow moving freeway traffic in 108 degree outside temps and the cabin a/c fan slowed in conjunction with the red 'Engine overheat' light. I couldn't pull off the freeway (101/405 FWY interchange) and instead dropped the windows and put the heater on high heat and full blast. The 'Engine overheat' light rapidly went orange and then extinguished. Once I was able to get back up to normal freeway speeds 10 mins later the a/c worked fine with no overheating. As a long time owner of two previous XJS V12s and a Jensen with the Lotus 907 block, I am careful to watch for overheating as it doesn't take much to warp an aluminum head.


I checked the water levels and the coolant is fine and the level is not going down over time. I have also pulled the dipstick and there's no emulsified oil in the pan or water vapor in the exhaust emissions so I don't think the heads are damaged. I have a compression test system and could run a comp test if that would show up any potential head damage.


A couple of times over the last twof months, the orange 'Engine overheat' light has come on, once in slow moving freeway traffic while it was in the low 90s outside and a second time last weekend after driving it about 8 miles in 72-75 degree weather while we were in a stationary line of cars in a drive through.


I used the same approach to immediately cool the car down, switching the interior heater up to high to get the overheat light to go out quickly.


I've read various posts about potential overheating causes, from stuck thermostats to failing water pumps. The new thermo went in less than 10K miles ago and was OEM, so it doesn't seem like it would have had enough time to fail, but the water pumps appear to be another story. Mine is an early XK, built in 2006 with B00231 as the last 6 digits of the VIN.


Separately I have noticed a creaking/clunking noise has appeared in the front end. If I'm reversing slowly and apply the brakes, it will creak. If I then put the car in drive and apply the brakes again, it will creak. Seems like there is a worn bushing somewhere in the front however I don't see any uneven tire wear as yet and the front alignment was done earlier this year when I replaced the front tires.


Any suggestions as to where to look for the intermittent overheating cause and the suspension knock?


Thanks in advance


Chris
2007 Jaguar XK Conv
1995 Jaguar XJ-S 6.0 Conv
1983 Theodore Cosworth T-83
1976 Jensen GT
1957 Ford Thunderbird

 

Sorry to hear Chris,

When you did the thermostat, is that the only thing you changed?

I recently purchased my 07 after having a 97 for the last 8 years, and was hoping jaguar would actually correct this issue. I was looking through some posts and found some things that may help.

First you may want to check the outer assembly as one member found that an internal piece cracked and wasn't diverting coolant back to the radiator. Instead it would just recirculate the warm coolant coming back from the engine.

I saw a few sites have the outer assembly which includes a thermostat and sensor for $144.00.

From past experience with my 97 I would change out the water pump if I ever got an overheat indicator. The plastic impellers weaken due to overheating and tend to fail. Even the later generation pumps (I know this from experience).
Replaced mine with a later generation pump and that lasted about three years. Didn't explode like the first because I caught it in time but the outer flange holding the fins had separated from the assembly. First time it happened I was fishing fins out of the engine.

You would think after all these years Jaguar would wise up and loose some of the plastic. At least the housings, I believe the XKR's have aluminum housings but they left the plastic on the XK. I guess were stuck with the plastic pumps.

Saw Beck/Arnley has a metal impeller but some well trusted members don't recommend using the metal one's. Something to do with coolant and wear.

I know in the XK8 forum they recommend changing the thermostat every 2 yrs. I think that was actually a Jag tech bulletin. I replaced 4 thermostats ,2 pumps, and two new sets of hoses over the 8 yrs I had mine and reached 220,000 on the Odometer before I passed her off to my father to enjoy.

I'm at 38K on my 07 and pretty sure at 50K I will do the following:
New Water Pump
New outer assembly with thermostat and sensor.
Maybe hoses (probably)

Figure a few bucks in prevention is much better than a Jaguar in need of an engine.

Not much help with the font end noise here but you may want to get it checked at and indy if you have one near by. Or maybe another member has more experience on the newer models.

Also saw in the owners manual that 5-30 oil is only good for 94 degrees and they use it for fuel economy. They had 0-40 for up to 122 degrees so I'm thinking winter and summer blend on my end. You may want to look in the handbook, I'd post the specs but don't have them handy and hope the above is close.

Good Luck and hope this helps.

 

Did you ever solve this (I have exactly what you've described).. "Separately I have noticed a creaking/clunking noise has appeared in the front end. If I'm reversing slowly and apply the brakes, it will creak. If I then put the car in drive and apply the brakes again, it will creak."

 

No issues with cooling, but I have replaced of the thermostat. As stated by my colleagues; why take chances.

As for grunts and creaks I have learned over these years that all jaguars are hard on bushings and spring isolators...

FWIW.

 

I sometimes get a clunk when shifting into Park. Anybody else? If so, any idea what causes the clunk?