Bosch high flow supercharger intercooler pump. V8R Jags

[J44EAG]

That is the hope, David.

A lower temperature 80C degree stat has just arrived via ebay supplied from KMS. It is physically of identical prime dimensions to the standard Jaguar 87C OE AJ86484.

The unit supplied by KMS is made by OE supplier Febi Bilstein under part number 17898. That is very re-assuring. Febi also supply the air damper units as Jaguar OE factory fit items. 17898 is also fitted to the Audi S8 as an OE factory part.

Gates also manufacture suitable OE stats.
Standard OE 87C stat is TH14387G1.
Non standard low temp 80C stat is TH14380G1 for high temperature environment or special application.

Images show the new Febi 80C stat alongside the Jaguar standard 87C unit.

Time permitting tomorrow, I`ll fit the Febi stat. The results might be quite intriguing.

Mike

[J44EAG]

If found a few minutes late yesterday afternoon to remove the OE 87 degree stat and fit the 80 degree unit. Refilled the system and burped the air.

Took the car for a short run to the shop. Temp showed OK on the guage. Heater working reasonably well. Stopped at the shop but notes fans running. Still running when I came back to the car. Checked levels which were OK. Started up and the temp gauge rose to normal within a minute. Drove back to the yard again with fans running again. Engine just warm to the touch. Removed the filler cap and noted coolant being constantly pushed out of the tank. Clearly, the low stat has unbalanced what Jaguar call a precision cooling system. So the old OE stat will have to go back in this morning.

So a little experiment gone wrong. The 80C stat is full open below the natural, normal engine temp of 91-93C. I suspect it was fully open at around 88C.The OE stat doesn`t open until fully until 95C beginning to open at 87C. 87 is what is marked on the stat.

There we go. Attempting to drop engine block temps in this manner, doesn`t work. I`ve learned something more. When you are at the cutting edge of research, development and modification, one occasionally expects a disaster! This is one of them!!

Mike

[Brakebuster]

'disaster' ? no ,

just an experiment proving another course of action is required for desired results, a learning curve that's all

keep up the cutting edge developments m8

BB

[J44EAG]

I think we call it a dose of automotive dysentery!

So a very sickly car is back to normal again now with no ill effects.

For sale, one ten minute use Audi A8 80C thermostat!

Loads learned. Fit only the 87C thermostat.

Mike

[davidr]

Oh well. If you don't try you don't know.
Never mind. You've learnt something I suppose and no harm done.
Now you'll have to dream up another cunning plan.

[J44EAG]

It seemed like a good idea at the time....

Right, where`s that triple pass Chinese inter-cooler rad? I think I put it in the heads. Hope its not been pee`d on.

Mike

[ptjs1]

Mike,

I can't profess to understand the intricacies of the xjr cooling system but I'm not quite sure why you experienced those symptoms just because a stat would open earlier. I also can't see why the fans would be running more on a stat that's opening earlier?

Perhaps it's possible that the stat wasn't functioning correctly? Wouldn't it be worth testing the stat in hot water etc before condemning the theory? Also, I'd run the car with that 80 stat but with k couplers and a temp gauge on various areas (stat housing on either side, rad side tank, top hose etc) plus obdii monitoring the temp as indicated to the ecu. It may be your theory is valid but you just have a dodgy stat.

What you were trying sounds reasonable although i do think you may get reduced heat output as per a permanently stuck open stat.

Let's give it another try!

Paul

[J44EAG]

My Mummy`s going to have another head fit. I can see it coming.

You and I taking over her kitchen with temperature probes, cameras, endoscopes, computers, boiling water, pie charts and linear graphs and an oscilloscope. No wonder you never get invited to stay for lunch! When you came for tea, almost all removable bits came off the Ranger Rover and got put on her best wheelie bin. It took her two days to get over that.

Oh, and another thing. She wants to know why you were standing on an upturned builders bucket. I`m not sure she understood it was required so you could undo your RR header tank cap. I`ve tried to teach her preventative maintenance but I think its a lost cause.

Anyway. The honking XJR fault certainly points towards a dicky 80C stat.

Mike

[irishjag]

Mike
I have the front bumper off at the moment to attend to a few things including a replacing a broken headlamp jet, a broken parking sensor, investigating a problem with low flow from the windscreen washer pump and replacing HID bulbs..

So as usual with these things the number of jobs has grown, after taking off the valance and all the rusted fixings found the valance undertray and the left wheel arch liner broken and needing repair.

Also i noticed when I started the engine to move the steering to get at some of the fixings I found the source of a noise I've noticed when just the ignition is on. Its the supercharger water pump and it sounds like its on its last legs, not healthy at all.

So I'm thinking its time to replace it and replace with the Bosch unit you fitted.
I have to say I'm staggered (and a bit intimidated) by the complexity of this car. I think I've counted at least four rads at the front!
Bit more than the xjs and a lot less room!

So to my questions, I've read a bit on taking out this pump and one thing that's talked about a lot is the difficulties in refilling and getting the air our of the cooling system.
When you take out the pump do you pinch the pipes to prevent coolant loss or just let it run out?
Whats the procedure for refilling and getting the air out?
There is stuff about a fill/vent point on the supercharger and having to have the expansion tank above this when refilling by putting the car on ramps at the front?
Whats the spec of the coolant to refill?
Any advice gratefully accepted!

[J44EAG]

Hi Chris.

What you found as regards the corroded and broken parts is pretty common. No surprises there.

Two electric pumps lurk in the 4.2 XJR. Both look similar but are in fact rather different. Removing the header tank will reveal the aux heater pump which is a long way down in the depths and just to the rear and off side of the main cooler rad. Like all electric pumps, they don`t last for ever. If replacing, stick to the standard Hella Jaguar OE unit. That pump like the S/C intercooler pump, runs all the time the ignition is switched on.

As regards the S/C pump, again that is Hella Jaguar OE in standard form. Again it runs when the ignition is on. That pump is only accessible with the bumper cover removed. Its a fiddle to get off and is at the bottom of the inter-cooler rad right at the bottom left below the crash bar. I got a pair of small ebay screw hose clamps to crimp the hoses but space was so tight I gave that idea up and just dumped all the coolant into a large ice cream tub whilst I fitted the new Bosch pump from AVT. You will find getting the new and slightly larger Bosch pump in place to be a tight fit with the mounting clamp needing some mods and a longer bolt. I ended up using cable ties which made securing the new pump to the fixed part of the bracket somewhat easier.

I wrote an article for the magazine about this pump change job. It has sat with our Nigel for many months but is due for publication in the next magazine edition. (April 2018) If you can wait a bit longer, then you will see it at the end of the month.

Just let the coolant drop from the car and recover in a container. Refilling is not difficult. Switch on the ignition to run the S/C and heater pumps. Fill via the header tank although ideally there is a fill point on the top of the S/C cowhorn manifold but needs a 17 or 19mm hex driver to screw out. The fill is at the highest point but if required a bleed can be done by just releasing on of the inter-cooler hoses quickly to let the air out. Also note the bleed screw on the header tank. Just top the system up, squeeze hoses, top up, take for a run, adjust level and make sure the heater system has some heat occurring. Despite the fact that the main engine cooling and inter-cooling circuits operate independently, they share the same header tank. That is nothing to worry about. Just burp a bit of air out, check levels and the system will quickly settle down.

What you are going through is little different from what I spent my first eighteen months of ownership doing. 80k miles of overhaul needed and once done, the car is good to go again for another 80k.

Mike

Yes, the XJR/XKR and XFR 4.2 S/C units are a complex bit of kit. Great whilst they are going but sometimes painful when repairs are required. The price we have to pay for having performance cars.

[irishjag]

Thanks Mike

First thing is to source one of the Bosch Pumps.
Whats the spec/type of the coolant in the Xjr?

Regards

Chris

[J44EAG]

AVT on ebay. (Advanced Vehicle Tuning) for the pump. They are an Essex based company.

I use standard orange/pink antifreeze from Halfords specifically for ali engines. Do not use blue antifreeze which is for mixed metal power units. Spec for the antifreeze is in the drivers owners handbook.

Mike

[irishjag]

Thanks Mike

Is this the same pump;

https://www.amazon.co.uk/Bosch-03920220 ... B00BHKX9PA

Its following a link earlier in the thread and a good bit cheaper (99 sterling) than the one from AVT (125 sterling)
Probably doesn't include the Bosch connector plug but I can pick one of these up for not a lot

Regards

Chris

[J44EAG]

I really can`t be certain that it is the same pump, Chris. This one in the Amazon advert may well be for just the auxiliary heater circuit. Whilst both pumps look very similar, the heater pump is a much smaller unit. The best thing to do would be to contact that supplier and ask the specific question. Is the pump a heater pump or for the supercharger inter-cooler circuit? Otherwise t he guessing game will usually end in tears!

Quite frankly, I`d just get the AVT unit and be done with it. It will do the job first time around. Make sure you are buying for the Jaguar rather than for the other common AVT pump which is for a Merc. Part number matching with the Bosch gear is frequently a hapless task. The details are often kept well hidden.

Mike

[irishjag]

Fair point Mike.
I'll go with the Jag AVT one
Thanks