Auxiliary heating pump Information/discussion article xj350

[BillDag]

In the light of little information on the auxiliary heating pump I Have decided to post this as a information/discussion article so input is welcome.

A quick background, the heating on the drivers side (right hand) is be poor to non-existent.
Flushed the heater matrix little or no improvement.
Then found in the manual there should be water movement in the header tanks with the ignition on an engine not running. Remove fuses in turn to the auxiliary heating pump supercharger intercooler pump. Remove the air bleed plug on the top of the intercooler with the auxiliary heater pump fuse removed, I got someone to turn on the ignition and had water movement replaced bleed plug, so supercharger pump working.
After fruitless attempts at trying to discern whether the auxiliary heater pump was running by touching and listening with a stethoscope I still couldn't decide whether it was running or not.
So decided to remove it. (I decided to remove the front panel of the under tray so as to drain the coolant rather than have it go everywhere undoing in the hoses) gaining access to the pump is not that difficult removal of the header tank and the top radiator hose, the worst part releasing the hoses from their spigots.

On the bench the pump did not run so I decided to strip it, If there's interest I will described that with photos later (If I can find out how to post them). The fault the brushes worn out, made up new brushes and got the pump running, which is exceedingly quiet and smooth running no wonder is difficult to ascertain if it is when in the motor.

As there are alternatives/upgrades for the supercharger pump I thought I'd take the opportunity of trying to ascertain the performance of the auxiliary heater pump, results you can read below.

From my investigations there seems to be no substantial difference between any of the Bosch PAA series pumps. I can only assume the difference is in the impeller and scroll design to alter their outputs and may be the electric connection socket. How this account for a price variation from £32 to over £300 I really don't know? Further the assembly/part number only differs in the last three digits and as you can read below, these digits have little bearing as to the pumps output with the 039 pump having a lower output than the 034 etc.
Below is a link to the Bosch catalogue it is in PDF the pumps on page 118
https://www.silicon-ark.co.uk/datasheet ... otoren.pdf


I cannot find any information on the pump fitted to our car 086 or any alternative offered the only two suppliers making offerings of £163 and £146 respectively, not the end of the world I grant you but I do find it irksome when you see other models of these pumps being sold for £100 and more less.

I did read on another forum that Bosch only make four versions of this pump plus a 24 V version, which may be why I can only find information on five PAA pumps?

So could ours be the model 034 whose output would seem to be close to my first method of testing or the model 024 which again is close to my second method of testing.

As I said earlier your comments would be welcome, in the meantime I'll put my original repaired pump back in to check if the heater is working, if not it may mean heater matrix replacement (please no ) in any case I'm very tempted to purchase a model 034 at between £49-£55 depending on supplier.

Regards Bill Dagworthy.

Auxiliary heating pump on Jaguar X JR 350 2004.

Pump.
Bosch assembly number 0 392 020 086.
2R8H-18D473-bc.
On motor body.
PAA Y 12 V D 392 020 071.
Ford. 1W4H-18D-474- AA.

I can only find five PAA Bosch pumps with any spec associated with them they are all rated at 0.1 bar delivery pressure and one of these is 24 V.
Hence my figures against a 1 m head (0.098 bar).
Outlined below are the two methods I used testing the auxiliary heating pump from my car,I feel method 2 the more representative. As I have not be able been able to find any figures on the pump fitted to our cars (086) I feel this is the closest Iam likely to get without knowing resistance through the heater matrix (new) and the associated pipe work, leaving aside a proper test rig.

First method testing output. Discharge measured into a bucket
Pump inlet connected into bottom of a bucket water head 50 mm above inlet.
Pump discharge via 20 mm ID pipe standing upright 90° bend at outlet.
First attempt at 1 m head pump would not discharge/lift. Reduced head in three steps of 50 mm until pump discharge at 850 mm head.
Giving approximately 0.083 bar head pressure.
Average of two runs discharging into a bucket.
11 L in 45 seconds = 14 L a minute.

Second method testing output discharge measured into a bucket.
Pump inlet connected into bottom bracket.
Outlet vertical pipe pulled 90° bend at outlet height 13.5 mm ID the same ID as pump outlet.
Set at 1 m head (0.098 bar)
Average of two runs.
10.8 L in 1 minute 32 seconds = 7.2 L a minute.


Maybe of interest. Pump connected as in method two.
Outlet via 18 mm ID rubber hose and approximately 200 mm head 0.02 bar.
Discharge 12 L in 35 seconds approximately 20 L a minute.

The four Bosch PAA pumps I found information on being the same model as our 086 pumps as follows.

Part number 0392 020 039 delivery 530 dm3 hr (8.8 L a minute) delivery pressure 0.1 bar.

Part number 0392 020 034 delivery 750dm3 hr (12.5 L a minute) delivery pressure 0.1 bar.

Part number 0392 020 024 delivery 500dm3 hr (8.3 L a minute) delivery pressure 0.1 bar.

Part number 0392 020 064 delivery 1200 dm3 hr (20 L per minute) delivery pressure 0.1 bar.

The two pumps used for replacing upgrading supercharger intercoolers figures are as follows.

Part number 0392 022 002 delivery 1200 dm3 hr (20 L a minute) delivery pressure 0.3 bar.
Part number 0392 022 010 delivery 1400 dm3 hr (23 L a minute) delivery pressure 0.3

[BillDag]

Continuing investigation into no heat on driver's side.
Be for installing the repaired auxiliary heater pump I carried out some more flow tests.
This time only using 13.5 ID tubing as it is the same size as the pump outlet.

Results are below.
Retest of flow using 15mm copper pip (13.5mm I/D) Method of measuring discharging filling a bucket. level above Inlet to pump 150mm
(a) 1 Met head 11let in 60 Sec = 10.8 Let Min
(b) 1 met head 10let in 56sec = 10.2let Min
Average of two 10.5let Min

(c) 850mm Head 11let in47 Sec = 13.8let Min
(d) 850mm head 11let in 50sec = 13.2 let Min
Average of two = 13.5 let Min

Installed the repaired auxiliary heater pump. vented cooling system brought engine up to temperature 90° C.
As pointed out earlier the manual says you should see water movement in the header tank with the engine off but the ignition on so as to run the auxiliary heater pump and supercharged pump.
I removed the fuse the supercharger pump and filled the system then turned on the ignition sure enough lots of gurgling movement of water so the auxiliary pump is moving water. Carried on venting cooling system with both pumps switched on, I found that once the system was full there is water movement in the header tank but it is very slight. Run engine topping up as necessary and brought to 90°c temperature.
Measured the heat output of the heating system set to maximum on both sides of the car the figures are below.
Cabin heat set to max on both sides.
Ambient air temperature 20c. Output on each side.
Left Passenger Foot well vent 78c Left fascia vent 75c
Right Drive side Foot well vent 55c Left fascia vent 50c
Now those figures would probably keep you nice and warm but that's with an ambient air temperature of 20° C and in truth properly not looking for heating with the ambient.
But once the ambient temperature falls to 8° or 5° the best that you might get is an air off temperature of 40° to 30° which might not be enough.
Though that's a massive improvement on what I had before, but obviously there is still some restriction in the cabin heater matrix.
I haven't yet decided whether to try more flashing or to install a new heater core.
A new heater core is in the region of £150 so again not the end of the world, but there does appear a lot of work involved in fitting it so will investigate further.
Bill Dag
The irony is my wife does not like a lot of heat in the car Perhaps I should let her drive

[J44EAG]

My congratulations on a very well produced and detailed write up on the heating/cooling system, Bill. Perhaps an article for the magazine would be good?

The internal cabin heater matrix is indeed a twin cored unit with feed and return supply pipes becoming bifurcated at the core in order that both passenger and driver can vary the heat output within their own area of occupation. However that part of the matrix does exhibit well known issues as these cars have aged. The core pipes are of small diameter and are prone to blockage with coolant crud. Somewhat strangely, this blockage usually manifests itself in the drivers side of the core. I have such an issue currently with my own car. Access to the heater matrix is via the passenger foot-well, removing the glove box and various other components to gain access. That`s fine if you are a young and physically double jointed flexible owner who doesn`t mind a morning of severe contortion spent bent double in the foot-well of a car to remove and refit a new core. The independent Jaguar maintenance garage I use was on this occasion somewhat resistive to undertaking removal and replacement due to the awkwardness and painful nature of the work. In addition, at that time, (Feb2018) the heater matrix was not available from Jaguar but a new supply was expected to hit the shelves within a couple of weeks. Hopefully that is now the case.

The garage did manage to restore some of the drivers heat flow in my car but it still remains markedly less than the passenger side. After the garage intervention, I bought a couple of cans of rad flush with the intention of attempting a chemical clearance. This would have meant removal of as much coolant as I could get from the engine, pipes, radiators, etc, refilling with rad flush and water, running for a few hours, draining out the flushing solution and refilling with a fresh coolant mix. Not being as enthusiastic as I perhaps would have been a few years ago, I regret my sciatica and disc collapse has stopped me taking the idea further. I was also concerned that the rad flush solution might reveal perforations in the matrix and that I might end up with a cabin atmosphere that resembled a sauna. As a result, unless I now go back to the garage and have a new matrix installed, I`m likely to have a rather chilly winter driving period ahead.

Mike