This post is an attempt to summarize a couple of key points that, while almost all of this appears elsewhere in the excelent instructions available, these points do not all appear in any single document that I could find. Hope this summary helps you when you replace your first water pump.

1) Use Gus' Jagrepar.com for further instructions or as further reference.

2) When you order the water pump, don't order the O-Ring. At Jaguars direction, newly manufactured water pumps have a tapered molded metal housing that by design eliminates the need for the seperate O Ring.

You will need a gasket, make sure it is part of the item you purchase.

3) Our forum's concensus is: Do not order the metal fin impellers. The car was designed for the cavitation provided by the plastic impeller not the metal ones.

4) FYI, there is a TSB about the original water pumps (pre 1999 as I recall) having black plastic impellers that disintergrate. This is 2015. While pumps with defective black plastic impellers might still be in your car, I can't imagine any of those are still being sold. Back when they were, impeller color was important. The TSB references black plastic being replaced by white impellers. This is no longer true, new properly made pumps do and can have black impellers.

5) Tools:

5/8 inch socket used on the belt's auto tensioner. Move it counter clock wise to release tension.

5/16 inch socket. (this is good for both the water pump mounting bolts and the 3 bolts hoding the belt's pully on the water pump).

Torque Wrench - but don't forget 5/16 inch sockets are usually smaller. Be sure you have a way to connect your 5/16 socket to your torque wrench before you start.

Hi Tack Gasket Sealant (about $7 at Auto Zone)- this keeps the gasket centered and attached to the water pump as you move it down and around to install it.

Small flat blade screwdriver (used to pull the clips on the telescoping hood braces back just a little bit to release the brace from the hood/bonnett. Guard these clips with a spare finger while moving them - there are way too many stories of them flying off into the black abyss of your driveway).

3 foot long wood dowel brace to support the hood while you move from telescoping brace #1 to work on brace #2. The single brace will not support the hood and the unfastened brace will naturally extend fully - Since it is extended, it will lie on top of engine components that now have no clearance with the hood if it closed. Things will break, bend, and dent if the hood closed on top if it.

Note: There is a hole in each of the hood's mounting brackets that some use as a safety - insert a large metal screwdriver in it or something. Physics being what it is, I never got comfortable with that. There is just way too much leverage in a 6 foot long hood with 18 square feet of wind exposure for my comfort. I always picture the damage of an errant screwdriver end flapping around or the incredible pressure this would place on the hood bracket. I'm probably over cautious - but its up to you. I use the wood brace to prop up the hood.

[I hate to have learned things like this the hard way but I did so, a warning for you: DO NOT put one end of the wood brace on the plastic "Jaguar" covers even for just a second. IT WILL crack them with just the slightest pressure]

Find a soccer ball, basketball or something you can safely lay on top of the engine as a safety buffer if the hood manages to find a way to blow closed in the wind while you are working on it.

Installation Key Points:

Water pump to engine torque: 8 foot pounds + 90 degrees
Pully to water pump torque: 12 foot pounds + 90 degrees

Of course you can not fully tighten the pully to water pump bolts until the belt is back on but do tighten the 3 bolts as much as you can to get the pulley in place and in alignment. Here's why: It turns out that the tolerance is much tighter than you'd ever expect. If the pully has any front/back play or wiggle you will not be able to get the belt back on. The pulley must be in its proper position for the belt to fit over the lip on the pulley.

Hope this helps.

 

Most bolts on this model of Jaguar are metric.

 

Yes I was surprised too. 5/16 is not a common size in any of my kits, went through the metric sizes first. Anyway the size is correct at 5/16.

 

I'm still leaning towards metric on both bolt heads. Probably 8mm if a 5/16 happened to fit.

The bolts themselves are listed in the parts catalog as M6, meaning 6mm thread.

The five pump bolts are M6 x 50mm.

 

So is it the consensus that a gasket sealant should be used even if the gasket provided with the waterpump is the metal kind that has the silicone seals built into the metal. I was under the impression that these sorts of gaskets should only be installed dry?
I have all the parts to do a full cooling system refresh that I have been putting off for lack of time, i figured I should not use any sealants on the thermostat housing or water pump seals since these are modern seals in which sealants are frowned upon. Also,
as a side note, the dealer hose that I ordered came with two new tension clamps making it a much better deal than the uro one available and It appears to be of a higher quality rubber which surprised me since I assumed uro was currently manufacturing the factory replacements.

 

I did the WP and T-stat stuff on my 03 XK8, using all OEM stuff. I cleaned my surfaces well and just put it back together using no other sealant with the gaskets that came with the parts.

 

I keep two short bolts on my bench to use for the service position. Slide the bolts thru the holes, put a nut on each end (no need to tighten) and it will never come off while you're working. Metric or SAE both work well.

Unless you are outside in some wind, there is really no pressure on the hinge.

 

Mike,

The bolts are a great idea. I couldn't thing of anything thick and short enough. I'll remember that for next time.

John

 

Plums, I always appreciate feedback like this. Who knows, maybe my year is different. Just to keep things clear for folks who look at this string months or years from now, I tried 8mm (too small) 9mm (too big), 5/16 great fit. I checked the math 5/16 is in fact right between the two:

8mm = .314961 inches
5/16 inches = .3125 inches
9mm = .354331 inches

I don't thing anything could have fit better than the 5/16 inch socket on my 1998, but Plums your look up seems pretty specific. Thanks for letting us know. I bet different years used different sizes or something. This will help someone down the road get their tools lined up for the job. Thanks again.

John

 

John,
at the risk of being pedantic, 5/16 = .3125 inches actually corresponds to 7.9375 mm.
Looks like 8mm *should* have been a nice fit.

 

Starting from the AJ26, all Jaguar V8 engines are metric.

JagNoir is correct when he says:

"5/16 = .3125 inches actually corresponds to 7.9375 mm"

All sockets are made slightly bigger than the nominal size,
but the allowance varies by manufacturer.

Perhaps the 5/16" had more slop than the 8mm and the
bolt head had some crud on it, or the 5/16" was a 12 point
while the 8mm was a 6 point. Another possibility is that
the engraving on sockets can be hard to see and what
you actually tried was not a 8mm, but a 7mm.

A 8mm six point socket will fit a clean, undamaged water pump
bolt obtained from Jaguar.

Future readers should try the 8mm six point first and only go to
an alternative if that does not work.

 

Great discussion. We're all in the same place - this post is to help folks down the road. I think we nailed it men.