A week ago I've noticed a radiator fan goes to higher and higher speeds, then I got 'engine temperature too high' warning and after that even the 'engine overheating' error (of course I switched off the engine immediately). After looking under the hood I noticed a leak near the expansion tank upper hose (one that goes from the engine). After removing the hose a broken nipple revealed. Well, that was disappointing, because there is no normal way to fix it without replacing a whole expansion tank. Anyways, I found a new nipple (made from metal) and temporarily attached it to the tank with a help of liquid rubber. The leak was fixed but of course the problem was much deeper, overheating continued and radiator was almost cool. Thinking that there might be a problem with a thermostat, I removed the hosing and saw a very sad picture. Photo attached. So the thermostat was broken as well as the housing. I found some pieces from a broken pipe, but not all of them. Already ordered this crappy plastic thermostat housing (assembled module - AJ811793). My main worry is that after removing the thermostat I started the car and nothing changed, overheating came up again (need to mention that I forgot to open the bleed screw so it might be air in cooling system). So the question is if there a chance that those remains from thermostat housing got deeper and damaged the pump? Or I 'just' need to replace that thermostat module?

I found these topics that are related, but would be great to hear from XF owners too.
https://www.jaguarforums.com/forum/x...ine-off-89439/
https://www.jaguarforums.com/forum/x...3-tips-114486/

 

There could be a number of things going on here. It's possible that the thermostat housing has found its way to the impeller of the water pump and damaged the vanes. Usually if the thermostat is stuck open, or in your case, disintegrated, the engine would remain cool. As you stated, if you didn't bleed the system, it's possible the water pump or a high spot in the coolant passages was air bound and you could have boiled the coolant since it is no longer under pressure and has no flow path. I would be nervous about what other damage the heat buildup may have done in spots without coolant. I would definitely remove the water pump and check its condition. Depending on mileage, I would probably just replace it since you already have it out. Check the condition of all the hoses, clamps, and the radiator as well. Hoses should be firm, but not hard or soft. Especially pay attention to the bottom radiator hose. This one is under a vacuum and if soft, the hose can collapse on itself and impede the flow. Definitely do a good coolant flush. Prestone makes a good, cheap Flush 'n Fill kit that you hook up a garden hose to flush the system. These are only $4 on Amazon and work great. Hopefully you find the broken pieces in the process. Once you get the cooling system sorted out, CHANGE THE OIL! It's probably been subjected to elevated engine temperatures and broken down in the process. While you're at it, check the oil level. Many people forget that engine oil isn't just for lubrication. It is also used to pull heat away from key engine components such as pistons and valve stems. One last thing to check to check is the accessory belt. A slipping belt will cause poor pump performance. With all that said, I think you already found your smoking gun judging from the pic. Good luck!

 

Thanks a lot for a clear reply. Already got Liqui Moly coolant system cleaner, will definitely try it. Also, thanks for noticing about oil, will do that. Currently I'm waiting for a thermostat assembly module, so will post here with pictures after I get it and try to replace it. Car mileage is about 50k miles, how is that for the pump?

 

Several members have had water pump issues with their '09 right around 50k. Not sure about the other years.

 

CTI, you don't say where in Russia you live, but things get pretty cold there in winter. Was your coolant OK to take winter temperatures ? Reason I ask, it the photos show a lot of damage. If it were me, I'd take off the water pump for inspection and probable replacement. 50K doesn't sound a lot of miles for trouble like this. Is this a V6 petrol or diesel ?

 

Fraser, I live in latitude of Moscow, so it isn't like supercold in winter. Also the car was in garage at nighttimes (not heated garage though). Never noticed any problems with coolant until this time (owning this car since october 2013). Even after fast and aggressive style driving, hardly even noticed the working fan. This particular trouble happened the next day after coming back from vacation (it was about 10°C when I left and about 20-25°C when I came back). First day it was okay I guess, so I suppose it was an instant breakdown. I will definitely take off the pump for an inspection. The engine is 4.2L V8 petrol.

 

Greetings CTN,
I am having the same problem with overheating on a S type 4.2 2006, 113k Km.
Can you confirm changing the thermostat housing cured all the issues. I am waiting for parts just now and just wait to confirm, I have it nailed.
reading other modal posts, it seems to affect all 4.2 v8 engines.

thanks

Bydand

 

Hello, bydand. Yes, changing the thermostat module cured the issue. Thing is, that if you are having the same issue with broken inner housing you have to remove the water pump to get the missing piece out. I was lucky to find this piece in the pump, leaving the pump itself unbroken. Also, you need to drain the coolant before these procedures (I recommend to change the coolant). Finally, after getting all done and filling the coolant again, you may need to get the air out of the cooling system. In my case, the air was blocking coolant somewhere in radiator. So, in order to get rid of the air you need to place a car uphill with the 'nose' up and push gas while standing still to spin the pump faster and make the air in coolant system go up. Good luck with your repair.

 

Ctn,

Thanks for getting back to me.
I am getting rather good at flushing and venting the system now, as had just changed out the DCCV when this happened and yes I will be doing all your suggestions as above.

Will be changing out the Thermostat housing and replacing hoses as managed to pop one on the TB to engine once they arrive from the UK.

Thanks again for your post which pointed me in the right direction.

Bydand

 

No problem, bydand, also, make sure that after removing hoses, you install them back correctly, so nothing will be in contact with the engine belt. I failed to do that with crossing two hoses in the wrong order and after a while one of the hoses that was very close to the engine belt got eventually worn out because it was contacting with the belt.

 

Ctn,

I bet I know which hose that was. The one from the thermostat housing to the DCCV valve. about Dia 19mm, I was working on the other end during the DCCV change out and it was a bit of an octopus.

The hose is also very close to the belt pulley if you do not align it correctly when on the DCCV.

I take a lot of photos when working on the car as it acts as a good reference, to refer back to when I forget which way around things go.

There are a couple of useful tools required when working on the cooling system.

1/. Draper expert 89793 Remote Hose Clip Pliers

2/.Washing up liquid.

The remote hose clip pliers make the removal and refitting of hose clips, if not easy, then at least manageable.

The washing up liquid, helps make the hose and hose clips slide on, and be able to twist when in position, so as the hose is straight, & in alignment with all the lettering and numbers on the hose.

Thanks again for your advice, & suggestions on this useful post.

Bydand

 

I was about the post the exact same symptoms with my 09, then I saw this thread. Problem is my impeller is in perfect condition and I cannot find the broken off plastic. Did you change the thermostat housing or just the thermostat?
Here are some picture of my 09 XF.
http://1drv.ms/1qEegMM


It's very odd that both pieces broke exactly the same way.

 

Edit:
After searching around it's not odd that we have the same problem, this appears to be a very common issue going back many years on the 4.2 liter AJ8. I called the dealership, they have 6 of the housings in stock but only 2 water pumps, guess that says it all doesn't it? I have 85k miles and figured I would change the water pump also since it's off, but I can't find the debris and don't want it to dislodge and destroy a new pump..

 

What very Nice photos.

You will have to replace the thermostat housing complete AJ 811793

I am sure the water pump can chew that bit of plastic no problem, I would be more worried about it causing a restriction somewhere.

I have attached the cooling dia for the 4.2 v8 see on page 9. its for the s type but same engine.

May be have a look in the pipework and try flushing/back flushing through the coolant system with a water hose to dislodge any broken parts of housing.

I was thinking of the lower rad hose which has the restriction to flow water through to the oil cooler, but that is on the up stream side of the pump/housing.

see the treads by cnr further up this post and some good comments on the XK board all to do with this issue.

Would you mind telling me what indication you had of this problem.

Now would also be a good time to change the serpentine belt, and check the idler, and tensioner bearings. (its an ill wind as they say)

checking my mileage mine would have failed at 68,484 miles.

 

Barrett motor cars of San Antonio, are quoting $81.64 for the housing on line. don't know if that compare with what you have been quoted.


Just a quick one, have you had any issues with the rear diff. Noise, leaks oil changed?. XF 2009 4.2 around about 50K

good luck.

 

Thanks bydand! I just uploaded more pics of tonight's progress, it's a tedious process getting to the bolts on the housing and the bottom of the throttle body. Everything is apart, waiting to be cleaned up and reassembled tomorrow. I will try to find any debris that I can, visually first then I am going to use the garden hose and blow out everything I can.


I found a surprise inside the plenum, as you can see in the pictures the bottom is full of oil. Is this normal or do I need to redo the PCV system? Any thoughts?


The new thermostat housing was $157 out the door at Autobahn in Ft. Worth, it was robbery, but they had 6 in stock...


Is there a process needed to purge the cooling system of air?

 

Funny you ask! I have an ongoing issue with the diff. I bought my car from Autobahn, at 75000 miles and nearing the end of my aftermarket warranty, I started hearing a lot of low rumbling from the rear at high speed and a clunk when going from forward to reverse of vice versa. Autobahn said it was normal, I knew better, so took it to Park Place. They diagnosed a bad diff, replaced the axels, drive shaft and diff. Now I have a loud clunk anytime the tension is changed in the drive train. Park Place cannot find the problem and I am just about at the end of my rope with them.

 

The reason I asked was that I was looking for a newer previously owned Jaguar, and one of the options was a XF 4.2 or XF 4.2 with blower.

Which were 2008/2009 low mileage and reasonability cheap. The only issues which were coming up on the various jaguar boards were the odd water pump, and the rear differential issues.

If you look two posts down someone else is also having issues? More of the same. Glad I gave that idea a miss.

https://www.jaguarforums.com/forum/x...ential-124070/

 

The vast majority of water pump issues are related to the 5.0L XF not the 4.2L. Search the forums for water pump and you'll see exactly what I mean.

 

Your are further ahead than I am, My thermostat housing has been delivered to the UK, which is unfortunate since I am in SA.

Both my Audi A4 and Volvo XC 70 had some oil carry over on the air manifold side when opening.

If you have no sludge waxy deposits in the take off hoses from the cam covers, and depending on what oil you are using. I don't think this is an issue.

I suspect you have been running hot so it will have thrown up more than usual oil mist. Are you running fully synthetic?

Any long freeway miles, spirited driving (hard not to) Just before stopping for R&R?

Is you oil consumption minimal between oil changes, leaks excluded?

If so I would not worry, its just carry over.

Venting the cooling system.

Topped off the expansion tank, my car was on ramps so the nose was up, see Cnt comments in the posts above.

Have a good look around for leaks all the time you are doing this venting, topping off.

Bring it up to normal temp at tick over, and keep an eye on the expansion tank with the cap off and bleed screw on the expansion tank loose.

Top back up to normal level and refit expansion tank cap. This should pressure up the system and some air will bleed off from the vent screw.

Then rev the engine lightly, max is only 4K.

When you have liquid coolant coming from the bleed screw on the expansion tank close it.

Take for a test drive, I live on a hill, so monitoring temperatures and hi temp low coolant level etc have a little drive. This vented more air out the system.

I put another two litres in when I came back after about 1 km. and bled the bleed screw again.

I will leave you to decide what and when to add the coolant to the water.

There is a drain valve on the left side of the radiator, your drivers side. I changed my coolant out completely, and will have to again now.

Montior the levels and coolant temperatures while your driving there after until you feel confident, all the air has gone from the system.

With may OBD reader half way on the coolant thermometer gauge was about 92deg C, getting hot and over 97 to 105 deg C.

regards


Bydand