I'm trying to replace all the heater & radiator hoses under the hood. They're all 20 years old and well overdue for replacement. While replacing the 'Spider/Octopus' hose I noticed the Aux hoses but didn't attempt to replace them since they aren't leaking yet. Since the Norma coupling on the 'Spider' hose was leaking I wanted to get it resolved first. But now that the 'Spider' hose is done I'm moving on to the hoses under the intake. I'd like to tackle the Aux hoses at the same time.

Anyway... While working under the hood I've continued to examine these Aux hoses and I'm stumped as to how to remove/replace one of the Aux hoses. (At least one.) The problem hose as I see it is hose #5 on the diagram below (and maybe hose #4 as well) ...


Auxiliary Heater Hose Diagram (Rear view)

The pump end of this hose is down under the firewall where I can't see it. I've tried to feel along the hose under the firewall but I can't find the end of the hose. How on earth do you access the clamp on the pump end of this hose? If I remove the Auxiliary valve (#3 in the diagram above) will that provide the visibility and access I need to get at this end of the hose?

I crawled under the car in the hopes that I would have better access from underneath but I don't see any access from the bottom at all.

I reviewed the shop manual & "Gus's" notes but I didn't see any information on how to remove this hose end. Gus's notes show removing the exhaust cat to remove the pump from below the car but I REALLY don't want to have to remove the cat. I'm not even sure I can. Access to the cat mounting bolts/clamps is one problem but removing them is probably impossible. I'm sure they're frozen solid and no amount of rust penetrant (Blaster) will help. Nor am I willing or able to drill out the remains of the busted bolts. I'm too old for that. And I don't even want to think about separating exhaust pipes that have been clamped together.

I'm hoping someone who's already tackled this hose has a better idea.

Thanks again for the help.

 

Cat, I have yet to see a way to get to the hose clamps for #4 and #5 with the pump in place beyond hiring elves to assist.

It is doable from underneath the car without removing the exhaust or the converter. You do definitely want to remove the aux valve as you will need this room. Having it out also get more light on the pump. Getting all four corners of the car on stands (so you can get far enough back to reach it squarely) helps. Track down 18" or so of socket extensions and a small head lamp so you can see up to it. When you are looking for it, it is almost exactly in line with the firewall and the bell housing. Be prepared that the rubber shock mounts that retain the bolts for it will probably break and will need to be replaced. Once its unbolted it comes out the top in the space where the valve would live. To my memory its retained with two or three 8mm bolts. If you have a helper they may be able to help guide the socket from the top while you work from the bottom, especially if you have pulled the valve body.

Hopefully some of that is helpful.

 

If you are tackling the hoses under the intake, you will have to have the intake and throttle body off, which will free up a LOT of space for access to the pump/valve. You might want to look into replacing the brushes in the pump as well at that time. They are known to wear off and let the pump die, but are cheap and easy to fix if you have access.

Best of luck, keep us posted.

 

I think it is helpful. I was able to see the hose ends (I think) when I was under the car but it didn't look like I would be able to get to it from below. I'll try the extensions (I have plenty).

A few questions though. There's an electrical wire that goes to the front of the solenoid on the Aux valve. How is that wire removed. The rubber block the wires feed into doesn't look like a connector.

And where are the rubber bushings? On the pump or the valve?

 

Do not try to disconnect the wiring from the front of the valve body / solenoid. That is the protection cover for wires leading in. Its connector is on the firewall above the valve. You should see a black connector and a white connector attached to the bracket that supports the unit. Unclip the connector, bring it out and then disconnect there.

To my memory (please jump in if I am incorrect), the pump has the same type of isolating rubber bolts that support the airbox (apologies as I can't remember the official name). As they age they tend to twist then split under the stress of removal. There are two or three of them and are relatively expensive from the dealer or parts house.

Also apologies if I am incorrect on how the pump is attached, there may be a running change that I am unaware of.

 

TropiCat,
The pump and valve are attached to a mounting plate secured with four 'instrumount' fittings - two at the top and two at the bottom. The latter can be reached from underneath using extensions as extheaterkid describes, although they may twist apart if the threads are rusty. Top ones should be fine as they're accessible.

The rest of the job can be done from above. The whole pump and valve asssembly will come out from the top with a little juggling after removal of the TB and coolant expansion tank.


Take a look at this thread from RaceDiagnostics:
https://www.jaguarforums.com/forum/x...41/#post752880

He removed the valve before extracting the pump bracket, but I found it all came out in one piece.

A couple of points:

• If you're replacing all the hoses, then I'd recommend cutting off the ones that attach to the heater pipes on the bulkhead. Saves a fight and you don't want any damage to those pipes...
• The replacement for hose #4 in your diagram has been re-engineered and looks rather different. I found it works OK but didn't route quite as nicely as the original
• Hose #6 is pricey as it includes a non-return valve
• Do consider replacing the brushes in the pump while it's out as fmertz suggests

Once the octopus connections and instrumounts were released I was able to remove the bracket complete with both pump and valve by pulling upwards and tilting anticlockwise (looking toward the rear). This gives better access to disconnect the two electrical connectors on the way out


Parts:

4 MJB6720AC
5 MJA6721AG
6 MJA6739AC

 

What he said ^^^. Yes it is impossible to replace those hoses to the heater pump (aux A/C pump) without removing the valve/pump assembly. I just had to replace my pump because the brushes were shot. I'd be surprised if your heater pump still works. My car actually failed safety inspection because the defroster didn't get hot - due to the pump not working. With the intake manifold and header tank removed, it's tricky, but the whole assembly on the bracket can be gotten out from the top. There are two nuts on the bottom of the bracket that can be got to from the bottom with long extensions without removing the cat.

 

Wow. After reviewing the thread recommended by michaelh I'm not sure I'm man enough for this operation. Since I need to remove the intake to replace the heater hoses underneath I'll take a crack at it and see how far I get. The throttle body is easy (not that I've done it half a dozen times) and the intake looks doable. But I'm willing to admit that I may be overmatched where the Aux pump is concerned. I'll have to see if I can find the rubber insulator/bushings parts before I get started. The last thing I need is to destroy one of these silly things and then find out I can't replace them. Yuck.

Anyway, thanks all for the ... 'encouragement'. I think.

 

The rubber mounts are still available from Jaguar, and they are likely to break on removal.

 

I was pleasantly surprised that this job turned out to be easier than I'd expected (which seldom happens). It may be that the A/C pipe on the 4.2L is more of an obstruction?
It also helps accessibility to the firewall hose connections if you remove both the coolant expansion tank and the bracket that attaches it to the car.

The 'Instrumounts' do have a hexagonal shape at the bottom of the threads that will take an open-ended spanner to hold still while the nut is undone IF you can get one on there:




The part # is MNA6730AB. Available from Jaguar today for the princely sum of $32.51 each
...but generally available elsewhere for around $4-5

Luckily, they all came loose for me, but I swopped bottom for top as the tops were in better condition and they are easier to get to.

 

More questions please. I crawled under the car again. It's harder than it used to be to crawl around under the car. It's also a chore figuring out where to place the jack stands, but that's another problem.

Anyway, after looking at things from the bottom again I tried to take a photo but I couldn't get the focus correct so please forgive the fuzziness...



Are the 2 nuts in the image above the nuts I need to remove? And do I have to put a wrench on the 'instrumount' nut before attempting to remove the attaching nut shown in the image above? (I suspect that's how you prevent these things from disintegrating when installing/removing them, but that looks impossible given the lack of access from below - with the cat in the way.)

I was able to get a socket on both of the nuts shown above (10 mm) but I had to use a 'wobbly' extension to get the socket on them. This leads to the inevitable question of how on earth I get the nuts back on when putting things back together. Without a straight line to the nuts I don't think I'll get them back on without cross threading them.

Also, are there 2 independent mounting brackets? One for the Aux Valve and another for the Aux Pump? Or is it a single 'L' shaped bracket that both the valve and the pump are both mounted to?

Thanks again.

 

I don't remember there being any washers underneath them but, yes, those are the two nuts that hold the bottom of the bracket. You may be able to get a wrench on the instrumount from above? The threads in you pic look exceptionally clean, so you may find the nuts undo without a problem - mine did so.

Confess here that I had the cat & middle box out of the way by this time, but I *think* you should be able to get a hand up there to start the nuts?

Valve and pump are mounted on the same bracket, part #10 on the snip below taken from JEPC. #10 is attached to another bracket (#13, which doesn't need to be disturbed) via the 4 instrumounts.

You may or may not find a #9 - 'Water valve heatshield' - I have yet to see one.

 

Michaelh, thanks a bunch.

A single bracket makes this possible (I think). Can I separate the 2 spider hoses from the aux valve & the 2 aux hoses from the heater core, then remove the bracket bolts above the aux valve, and THEN remove the bracket & pump & aux hoses as an assembly? Or do I need to remove the aux hoses from the aux valve in order to remove the bracket w/ pump attached to gain enough clearance?

And I don't have a heatshield over the aux hoses. I can see them clearly from above.

I think I'm ready to give this a go now.

 

That's what I did. You will see from RaceDiagnostics' thread that it looks far too bulky to come out in one piece, but it did for me. If you do run into difficulty, you can separate the valve from the bracket once you have the instrumounts undone. It's held from behind by a pair of 8mm bolts.

I elected to cut the heater core hoses away from the bulkhead as I was replacing them anyway, and the thought of damaging the plumbing behind the firewall scared me.

Do remove the coolant reservoir bracket as it will give you slightly better access to the bulkhead connections. It's two bolts, and the lower one only needs to be loosened as its location is slotted.

I wonder if Jaguar dropped it early in production?

 

Thanks michaelh. I didn't realize that the expansion tank bracket could be removed. I thought it was part of the master cylinder housing. I'll look into it. Any additional clearance will be appreciated. I'm hoping with the intake out of the way the clearance will be all I can get but if the tank bracket can be removed too that's even better.