Hi, I've had an issue recently with my Jag XK 2008 4.2 80k with the cooling fans running longer that expected after commutes to and from work (20 miles). I've seen on here the likely suspect is a bad or sticky Thermostat. I have bought a replacement as well as a water pump as I've seen posts that recommend doing that at the same time.

Does anyone have a good guide or advice for doing this on a non supercharged XK? I've had a look on Youtube but can't find anything. I have also downloaded the manual (from link in this forum) so I can follow that but I have some questions that I hoping someone can help with.

1. Can I do this job without removing the bonnet / hood?
2. If answer to above is no then is it possible to remove the hood myself without help? (If so how)
3. Is it essential that I replace the throttle body gasket?
4. Do I need to drain all of the coolant prior to starting the job or is partially OK?
5. Is there anything else I need to be aware of prior to starting this job?

Thanks in advance for any advice.

 

Welcome to the forums Nick,

I've moved your question from General Tech Help to X150 forum. Members here with the same model will be able to help.

Graham

 

There is a thread here somewhere that gives a pretty good step by step, which I followed when I did the thermostat housing a few years ago now on my 2007 XK, I’ll see if I can locate it later.
Don’t need to remove the hood/bonnet. Think I drained all my coolant, as I was going to replace with new anyway. Didn’t replace the throttle body gasket.
Small hands really helps with this, as it is pretty tight in there.

 

1. Can I do this job without removing the bonnet / hood? Yes, but be sure to remove the struts to allow full access mode for the hood.
2. If answer to above is no then is it possible to remove the hood myself without help? (If so how) NA
3. Is it essential that I replace the throttle body gasket? not essential, but should be done at some point to avoid vacuum leaks
4. Do I need to drain all of the coolant prior to starting the job or is partially OK? partial is ok, but be prepared to lose several liters of coolant
5. Is there anything else I need to be aware of prior to starting this job? The bolts holding the water pump are very tight due to heat cycles, be very careful not to strpi them (I did and had to get socket type extractors which did a beautiful job, i would just buy them ahead of time)

 

See the stickies at the top of the forum for help with the water pump replacement;
XK/XKR - 'How To' / DIY Repair & Maintenance

SECTION 5 ENGINE
Water Pump Replacement - 4.2 NA

Still looking for that thermostat thread.

 

Ok, read this whole thread about your thermostat replacement:

https://www.jaguarforums.com/forum/x...rmostat-97933/

 

That's brilliant - really appreciate your help and advice. Thanks

 

If you buy the pipe outlet it comes with thermostat and temperature sensor already installed and does a complete fix I got code P128 so replaced the Thermostat only, 2 months later got the same code again inspected the thermostat and the houseing had cracked and was not holding the thermostat securely

 

As I thought the housing had broken internally as has so many others (sorry for the blurred picture) so I will need to replace both. I ordered the thermostat and housing anyway as well as a water pump, but removing the throttle body that joins onto the engine is a royal PIA to remove. I have managed to loosen all the bolts but just need to remove the union as shown in the 2nd picture before I can take it off. I have tried pulling on it and prising with a screwdriver but it doesn't appear to want to separate, does anyone have any ideas how it comes off? I can't find anything in the manual on this.

Thanks
Nick

UPDATE: I have managed to remove this by squeezing the neck to the fitting with some pilers while pulling - just need to figure how to remove belt and water pump now, hopefully that's in the manual. I'm hoping putting it back together again will be a lot easier.

 

I have managed to replace the Thermostat / housing and Water pump, its a job that I wouldn't like to do again in a hurry. Its a fiddly job that requires a lot of patience. Some of the bolt locations are difficult to get to. I did buy a smaller 1/4" socket set that helped a lot as well as some hose clamp pilers which are a must. Everything went back together ok with no bolts left over! I will keep checking the coolant level over the next week in case in drops a bit but hopefully it's all ok. I didn't replace the throttle body gasket or O -ring as unavailable at Jaguar dealer, but I cleaned them well and hopefully they'll be ok.

Thank you for all that helped, hopefully I can repay the favour in the future. Now time for a cool one!

 

Congrats!