I bought a used 2007 XK.

It reports "engine overheating" fairly predictably when idling or in slow traffic. I have not had a problem when on the highway.

I found the coolant low so topped it up. It didn't help.

I had the dealer look at it. They replaced the thermostat and said that the thermostat housing was cracked, so it was replaced as well.

Despite the repair, the problem continues.

I have now got myself an OBD scanner and driven the car with it hooked up to the OBD port. The car starts at <60 degrees (celcius), and the temp climbs to 100 and higher. At 120 is when the car reports a yellow warning message. I am stuck in traffic I find that putting the car in neutral and revving the engine RPM to 2500-3000 brings the engine temperature down to approximately 100. Similarly, when cruising the engine tends to like to run at 1000 rpm and can overheat. By manually shifting I can avoid the overheating message.

I have heard that earlier generations of this car had a problem with the water pump (plastic impellers), but it seems like this is not a problem on the 07 model.

I wonder what to try next. I dread bringing it back to the dealer. Granted there may have been a problem with the thermostat and housing, but given they returned it to me without resolving the problem I'm not a happy customer. Should I replace the water pump (or at least take it apart and see if the impeller is damaged)? If so, is this a reasonable DIY job for a mechanically inclined person to try on this car?

 

The t stat housing was probobly cracked externally and internally. When they break inside a piece of the inner housing usually goes down to the water pump and sticks in the impellors reducing the flow. Make sure they replaced the entire t stat housing. If they only replaced the t stat and cover the piece that breaks internally will not seal against the back of the t stat and cause poor coolant flow inside the engine and overheating. I always replace these now since theyre plastic and degrade.
You can pull the pump and clean the piece out and ide also look to make sure the entire housing was replaced.

 

After you topped up the system is the car still using/loosing coolant?

 

Thanks for the replies.

I think that the whole thermostat housing was replaced, as the cost for the part alone was over $200. If this still doesn't clarify what was replaced, what do I look for, and do I need to drain the system and remove the thermostat to tell what was replaced?

I never noticed the system losing coolant, and the dealer said that they did a pressure test and couldn't find a leak. I'm pretty sure that test was done before the thermostat was replaced, which would mean that it was not losing coolant. I suspect that at some point before I bought the car, it overheated and lost coolant at high temp, and nobody ever addressed the problem. I remember the cooling fans running after I turned the engine off when I test drove the car. The salesman said that was normal. I didn't know the quirks of the car and didn't question it. I know now that was a lie and the coolant was hot. The lack of a temp gague, and the lack of a message on the display panel (ie: it had not reached 120 degress when I turned off the engine) meant that I had no reason to doubt the salesperson's explanation.

So, if I go ahead and pull the pump, what do I need to have on hand? I presume I'll need at least a gasket and new coolant, if not a replacement pump. Where is the pump located?

 

Were it me - I would subscribe to AllData "one of our sponsors" before diving into this job. The front end of this engine is no big deal but it ain't like your old Chev 350 and the procedures to access and service the water pump need to be observed.

 

It is normal for the fans to run after shut dwon depending on what the ecu wants for engine heat and ac pressures. On high not normal, but low speed sure. Just because you paid for a housing doesnt meen it was replaced. But more than likely was, just sayin. I personally would go back and say the car is still overheating, it could also be a part warranty on the new part. You know what new meens??
N=never
e=ever
w=worked

 

Pump is at the front of the engine, and a new pump normally comes with its gasket, but you need to check. It is not usually necessary to replace the coolant, you can drain it down and store for re-use, however if it is due renewal, best to replace. Note that these OAT-type modern coolants last a long time, I believe it is around 5 years for Jaguar-recommended coolant.

 

Hmmmm... I always assumed that the timing belt would have to come off for a water pump replacement, making it a more complicated job. But I am aware that the AJV8 doesn't have a timing belt! I didn't realize that the timing chain didn't drive the water pump, though!

 

My understanding is that Ford used the Jaguar motor, with smaller displacement/hp in the 2002-05 Thunderbird. I wonder if the water pumps interchange? If so, a Ford part number water pump will probably be a lot cheaper than the Jaguar's. Has anyone checked this out?

 

okay first IF the water pump is bad it would be minutes to overheat without coolant flow. you can pull the bleeder off and start the engine to check flow. Itll pump out quickly. unless you just like spending money and changing parts to ease your mind

 

The water pump is external so only the main belt and one tension pulley needs to come off.

 

That's a good data point. It should help greatly when people are wondering about the waterpump. But then what about the possibility of pieces lodged in the waterpump like you mentioned? The waterpump would still have to come out in that case. How do you diagnose that one?

 

just takew it off and take them out of the impellors or the cavity behind the pump if there are any and reinstall the pump. steel shim gasket can be reused without issue too. Just loosen the 3 8mm holding the wtr pump pulley on then take the belt off only from the pump pulley nothing else and no need to take off the tensioner either. 5 8mm bolts hold it on and dont round off the heads by useing a wornout socket or 12 pointer. youll have to grind the heads off if you do and they do tend to seized alittle

 

This guy "Brutal". Can we clone him?

 

That sounds great! Will I need to remove the thermostat housing to get at the pump (that's part of the procedure I found on alldata)?

Also, I'm now hoping that I may not need a new pump. However, if I do find that the pump impeller has been damaged, I'd like to find a replacement pump that uses a metal one. (the jaguar replacement uses a plastic impeller). Any recommendations?

 

Do not use a metal impellor pump. They do not flow enough water. There s nothing wrong with the plastic ones. Ive seen metal ones that ive taken off put on by indies and the car overheat cause they dont flow properly. Theyre just a stamped flat blades not a nice curved one like the wheel of of turbo. Another case of oem being best. No you dont have to take off the t stat housing, you can work around it too. But i can also tell you that i would have taken it back again, if the hoses on the t stat housing are not put back correctly they wouldnt be able to properly bleed the system and it traps air. If thats the case. The throttle body coolant lines from the egr and the bleed hose from the housing to the coolant reservoir are the ones you have to pay attention to. If you have oither questions someone else will have to get. I have no work, made 10 hours for the week so far which is half assed hours for a day so im going home. Hell my 18yr old daughter making min wage is making more than i am this week, and people wonder why good techs eventually get out of the business
cheers

 

Brutal,
Asheville doesn't have a independent Jag/Land Rover shop??? Nice clean air and plenty of mountains to crawl up n' down.

 

I have a 2008 XKR Portfolio that has had the same issues.
First under warranty, replaced the thermostat last summer. Worked fine until this summer, it did it again. Under CPO warranty, replaced cooling fans.
After one week, so far so good. It seems when it is under warranty, dealer
is hesitant to do any extensive repairs. I am sure if it did not have coverage
I would have had a water pump replacement as well.

 

Don't know if I missed it but did you check to make sure the fans are coming on, as they should, at low speed and also have you checked the radiator to make sure it's not plugged ?

 

That would be too brutal altogether