2004 XJR

I need to replace the Auxiliary Water Pump. In addition, I am going to flush the heater core. I am a new Jag owner. While I used to work on BMWs quite a bit, working on Jags is a new experience. Are there any complementary preemptive projects I should undertake for the sake of convenience? Thanks

 

Replacing the auxiliary water pump should not be a big issue, but as you have to drain the cooling system I would look at how ll the hoses look like and replace the ones that do not look very good anymore. Furthermore, check how the hose connections of the radiator look like, these tend to disintegrate with time.

The one big job that is a sensible preventive measure is the replacement of the valley hose (if it has not been done before), but it I would not call it a project for the sake of convenience, as emptying the cooling system is nothing compared to the complete replacement job...

There are a number of threads regarding the valley hose replacement, here's one to give you an idea of the efforts involved:
https://www.jaguarforums.com/forum/x...valley-134108/

Best regards,

Thomas

 

Hi PowdyrdWyg,
If you are replacing the auxiliary water pump, you may want to look at the supercharger cooling pump as well. This is mounted very close behind the front bumper bar on the right hand side. It is very similar to the auxiliary water pump, but not the same. I believe Bosch make a compatible, but higher capacity unit that is also cheaper than the OEM pump. Failure of the supercharger pump causes Restricted Performance issues.
You might also check that your auxiliary pump is getting voltage, if it is not working. Both it and the supercharger pump are powered through relays in the front distribution box, on the right side of the engine bay. My supercharger pump wasn't bad, but the relay was. Changing the relay is possible, but it may be soldered into the circuit board, which makes it more complicated. I've done all this so let us know what you find.
Working on Jags (at least these ones) is very similar to other European cars of the same age. The workshop manuals are all available here on the forum. Look under the sticky posts at the top. Another great resource is JagRepair.com - Jaguar Repair Information Resource who have lots of useful information for these cars.

Pete M

 

After a cracked radiator tank, a cracked expansion tank, then a leaky water pump, I overhauled my cooling system instead of replacing the next weakest piece on at a time. Every last stinking hose. I almost skipped the valley hose because all of the accessible hoses actually appeared to be fine; no softness, no swelling or bulging, and they were probably OK to reuse. I balked at the valley hose due to the effort needed to remove the intake manifold for access, but finally bit the bullet and did it, and I'm glad I did, as that hose had not much time left. It was by far the worst hose on the car, very soft and quite well ballooned. That hose was absolutely going to be the next weakest piece of the cooling system and would leave me stranded somewhere when it blew. Oddly enough, the auxiliary pump is the one piece I did not replace, as I saw no need to.

You might look at replacing the main water pump as well as the auxiliary. It's EASY to get to, once the fan and shroud are out (which is more of a job than it ought to be...) and maybe the lower radiator hose (the one going across to the left side of the radiator.)

 

When I replaced the main water pump, I did not remove the fan. No need, there was enough space to work. What I removed, though, was the thermostat housing.

 

Mine was an XJ8, not an XJR, so no supercharger. I don't know what's different about that valley hose on the XJR, but what's in your picture is not what I had on my car. That upper part of the cooling system is different to clear the supercharger. Still, if the OP's main water pump is original, it's time, while he's in there.

Here's a shot from another thread of someone's 2003 S-type supercharged, and I've marked the valley hose I'm talking about. In my non-supercharged, that hose comes from the valley and turns 180 degrees to connect to the throttle body. I don't know where it goes in the supercharged cars, but I know it lives in a difficult thermal environment.

 

The picture I posted was to show that there is enough space for replacing the waterpump on SC cars without removing the fan. In the picture you can just see part of the valley hose,
Off course, being the same engine, in the X350 it looks like in the picture of the S-Type:



Best regards,
Thomas

 

Hi Thomas,
The original poster, PowdyrdWyg has as his tag a 2004 XJR, so this should all reference the SC engine.
In the SC engine there are two valley hoses. Valley hose 1 is for the coolant supply to the EGR valve, then a short loop from there to the TB, and then hose 2 is the return hose to the engine. The supply side is more usually degraded as the pressure is higher, but they are both subject to the same high temperatures.


SC Coolant diagram

Valley hoses

Valley hose to EGR, EGR to TB, TB return.

Pete M

 

Hi Pete,
I saw PowdyrdWyg's tag and what I posted refers to the supercharged engine.
Sorry to contradict, but there is only one hose routed directly underneath the supercharger, and that's the valley hose. The others are routed differently. I know that scheme and those hoses, the pictures I posted are from when I did the job myself on my SV8.

The following shows the rear of the supercharger before removal, and you can see only the one hose lurking underneath on the right side:


The other hose you refer to is not routed underneath the supercharger, but next to it on the left hand side, you can see it between the supercharger and the left cooler. I have routed it exactly how it was originally, and I am pretty sure that on my car the job was never done before:



Here's all the hoses I replaced at the time:


My car is also a MY2004 X350, so the routing should be the same as on PowdyrdWyg's car. As you say that both hoses would pass underneath the supercharger, it might be that on the X358 that you have the routing is different, or that someone changed the routing at a certain point of time.

Best regards,

Thomas

 

Yes you will be miles ahead to plan on replacing ALL cooling hoses as Wfooshee posted above. Yes there are a bunch! My 2005 STR had about 23 and your XJ's will be very similar if not identical. Otherwise you will be going back in again and again as the hoses individually fail and leak.

Also note this tip from Brutal one of our Jaguar factory technicians.
Slot the rear bolt hole on the blower after you take it off. Words of wisdom from a guy that ignored that great advice and of course had to go right back and remove the SC to fix a vacuum leak I created when removing and installing the blower.

It's in your picture here;




It is a real simple but useful trick!
Note that bolt is normally completely invisible because in this picture the SC elbow has been removed.

Were the EGR bolts much of a fight? They tend to get rusted solid and are difficult to remove.
.
.
.

 

I thought about slitting the rear bolt hole of the supercharger when I had it out of the car, but in the end I decided against it... call me mad,,,
No rust issues with the EGR bolts, everything came out fine.
Actually, I did not have issues with rusty bolts anywhere on the car, probably because it spent most of its life in Italy, where it did not see much salt on the roads. And here in Germany I limit the use during winter times to keep it that way.

Best regards,

Thomas

 

Hi Thomas,
Thanks for your input. I've reviewed the photos I took when I replaced my supercharger, and I'm sure both hoses on mine were routed under the supercharger. The alignment of the hose when fitted seems to naturally put it there. and when it reaches the back of the engine it also connects naturally to the TB or EGR. The connection on the thermostat housing is pointing down and back so that's where I fitted the hose. I will have a look at the manual to see it it shows it. I also used the pictures of an S-Type R rebuild for reference and they show it under the supercharger. It's a mystery.

Pete M

 

Hi Pete,

after looking, among other things, to this thread, where you also had some input

https://www.jaguarforums.com/forum/x...iagram-196243/

I think that my assumption about the change in design seems to be correct.

Here's why:
The hose you say is the second one that runs under the supercharger should be part no AJ811767. I do not recall having this hose in my car, it is also not to be seen on the picture with the hoses I posted. In the thread mentioned above, the pictures posted by jackra_1 of his 2005 XJR do not show it.

It's not the first time that the JLR parts catalogue is not helpful. In this case because it states that this hose is fitted to all supercharged engines of the X350 to X358 range.

But, if you look here

https://www.jagbits.com/product/AJ811767.html

the description is a bit different:
quote HOSE COOLANT FEED, WATER OUTLET TO EGR, RUNS UNDER SUPERCHARGER FITS 2007-2009 XJR FROM VIN H19623 ON AND 2006-2008 S-TYPE R FROM VIN N52048 ON. AJ88553 6R83-9Y438-BB 6R83-9Y438-BC (AJ811767) unquote

I think that this description is spot on and explains nicely why you have two valley hoses on your car and I only have one,

When I replaced the hoses on my car, I used the list published by WinterJag in this thread, which was spot on for my car (thanks WinterJag!):
https://www.jaguarforums.com/forum/x...ngines-189274/
He states for "...04-05-sc-engines..." and AJ811767 is not on the list.

What do you think? Mystery solved?

Best regards,

Thomas

 

Thanks, clubairth1. What does slotting the bolt hole accomplish?

I appreciate everyone’s responses. The point of this repair is to get my heater working again before it gets cold. Before replacing the pump, though, I need to confirm that it is not working and that there is no air in the system. I will look at overhauling the cooling system at a later date. My car has less than 90k miles, and all the hoses appear to be in good condition.

 

Hi PowdyrdWyg,
The intake elbow is bolted to the back of the supercharger, and normally the intake elbow is removed first. Access to the bolts from the intake elbow into the back of the supercharger is a little tight. There are also two very small bolts at the back of the intake elbow onto a mounting bracket, which are even harder to access. Only then can the bolt at the back of the supercharger be accessed for removal.
By slottting the hole at the back of the supercharger, it enables you to remove and refit the supercharger with the intake elbow already fitted. You can reach underneath the supercharger for that third bolt. This could save an hour's careful fiddling around with a head torch and mirrors.
I did this the hard way, without cutting the slot, and fitted the intake elbow after mounting the supercharger and tightening the three bolts to the correct torque. Interestingly, when I removed my supercharger, the bolt at the back was absent, but I suspect the PO had been at work. It fits with other discoveries I have made while working on the car.





Pete M

 

Good description from Pete M. Yes I also fought that bolt out and in 4 separate times and then slotted the bolt hole. Of course that was the last time I needed to remove the SC!
Yes I can see how a person would be tempted to just leave that bolt out too!
.
.
.

 

The auxiliary water pump is a Bosch, common in hundreds of vehicles, it costs a little and replacements are realy cheap, do not buy one branded by JLR, choose according to the thickness of the tubes and the square plug. The number is: 0 392 020 086, but it do not have to be identical. In fact, your pump is not broken, they last forever, only the brushes are gone, you can easily adapt them tfrom other devices by filing them a little. Replacing the electric part in the pump is also possible, the pump is divisible, you don't even have to drain the coolant, but whatever you prefer. Flushing the heater core is a waste of time, only a new one.

 

2004 XJR < 90k miles

So, I bled and topped up the system using the method posted by 34by151 on Jan 22, 2015.

- Coolant was just below “min” when I started, so I topped it up with Dex
- I used a mechanic’s stethoscope and could hear the aux pump whirring with the ignition switched on
- Unless minimal movement of coolant counts, at no point did I observe “signs of coolant flow” in the overflow tank, either with the aux pump only or with the engine running
- I never felt “pressure” (when squeezing) in any of the hoses, either with the aux pump only or with the engine running and at temp


There is no discernible increase in heat at 75 on the climate control; it’s just room-temp air. Turning it up to “HI” does produce heat but it’s less than my 2015 Jeep Cherokee (> 90k miles) that causes 1st degree burns at such a setting.

Next steps:

1. Does back-flushing the core really not accomplish anything? A post by motorcarman on Jan 8, 2018 suggests filling it with a flush solution (I have seen recommendations for the kind listed in the repair manual or white vinegar) and letting it sit overnight before flushing with water.
2. Others have recommended replacing the auxiliary water pump (which is not the pump for the supercharger), but first, mine sounds like it’s running, and second, if the engine is running and at temp, shouldn’t the primary water pump circulate the coolant through the core? What does the aux pump accomplish when the engine is running and at temp?

I don’t think the aux pump is the problem. So, the next step is to flush the core. I am new to some of this, so please forgive any incorrect assumptions.

 

Hi PowdyrdWyg,
It seems to point to a blocked heater core, which seems to be a common problem. If flushing it doesn't help, it is not an impossible task to replace it.
The purpose of the auxiliary pump is to maintain flow in the heater circuit at low revs. I think it was found that heater performance was insufficient at low rpm, so an electric pump was added. I can understand this, as my cruising speed of 100 Km/h equates to 1700 rpm, and my heater functions correctly.
At some stage before my ownership, the coolant in my car was converted from the orange (OAT) to the green (Ethylene Glycol) type. I know my water pump was replace by the previous owner, perhaps it was done then. If changing coolant types, it is important to flush the system completely, as the chemicals are incompatible and will form sludge if mixed together.

Pete M

 

Yes the problem is the heater core is above the engine. So until you get the RPM's up not enough to give good flow thru the heater core. The AUX pump makes sure the heater core is full so it can produce heat even at idle.

If flushing I would disconnect the heater hoses in the engine compartment and blast just the heater core. I don't generally do flushes but I have used this as I am a huge fan of Evapo-Rust and this is their version.
Evapo-Rust Thermocure-
Evapo-Rust Thermocure

I run it at least a week in the car in normal use. You can't over use this and when all the corrosion is in solution it won't attack anything else. But I have found these late model cars have zero or very few iron/steel parts. This is where all the corrosion and debris comes from. The last truck I did had 150K+ miles and still had 10+ year old factory Dex-Cool in it and I got zero junk out. The coolant looked the same as when I put it in the week before. So I think I kinda wasted my money but was glad to know the engine is now spotless!
.
.
.