# Leak from the water pump?



## Toxic (Oct 16, 2005)

Ok if im looking into the engine the fan at the front to the left has what looks like a round water pump attached to it. Is this the water pump that is replaced at the same time as the cam belt change? Because around the seal where it looks like the pump is screwed together there is a bright pink buildup like it is very slowly seeping coolant and drying on the outer rim. But not to the amount that you notice a loss in the bottle. Anyone know what this is? has a medium sized pipe coming from the top of it. Thanks


----------



## davidg (Sep 14, 2002)

Do you mean this :wink: [if so it is the secondary water pump]


----------



## Toxic (Oct 16, 2005)

Aye yes  thanks for that. Right where it joins together in the middle. It was the coolent colour around the seal. Looks like a very slow leak. I guess this will not cause too many problems? Audi would not have touched this in replacing the secondary air pump?


----------



## John-H (Jul 13, 2005)

That's the run on pump that keeps running for a few minuites after you turn the engine off, I think you mean. I had mine show exactly the same symptoms you describe. It's a slight seepage leak of the coolant which leaves the crusty purple stuff.

I took mine apart and cleaned up the gasket seals before putting it back together again. Seems to be OK now I think.


----------



## davidg (Sep 14, 2002)

John-H said:


> That's the run on pump that keeps running for a few minuites after you turn the engine off, I think you mean. I had mine show exactly the same symptoms you describe. It's a slight seepage leak of the coolant which leaves the crusty purple stuff.
> 
> I took mine apart and cleaned up the gasket seals before putting it back together again. Seems to be OK now I think.


John
Did you take the whole pump apart ?? ,,, looking at getting a new one as mine is rattling , slow , not runnig correctly .


----------



## John-H (Jul 13, 2005)

I took the screws out of the plumbed end. The rotor is driven by a rotating magnetic field from the motor and a magnet which is in the main body of the pump behind a sealed partition - so there are no wearing parts in the watery end and so there's no shaft to seal. This end is easy to take apart and clean however. You might find some debris has got in there. Take the pump off its pipes and take the screws out of the pipe fitting end. The rotor will withdraw against the pull of the magnet.

*EDIT 1:* I had to re-visit this repair so took some pictures. It seems that just cleaning and re-assembling still allowed a very slow leak. Then I found the underlying cause. It seems that the top housing sealing face can become distorted making it harder for the O ring to seal. This time I smeared a little Blue Hylomar gasket sealant onto the faces that the O ring seals against. Not too much to avoid the possibility of any oozing out inside. All faces were thuroughly cleaned with IPA prior to application.

After unscrewing the pump mounting the pump can be pulled high up above the reservoir, so when you take the pipes off you can avoid any fluid loss. Mark the pipe positions relative to the body to avoid twisting the pipes when re-assembled.










Push some rubber bungs into the pipe ends to seal.










After removing the four screws, here are all the parts in exploded order.










Give all the parts a careful clean. A little petrollium jelly on the shaft will help initial lubrication.










You might be able to see the sealing face distortion in the reflection off the sealing face. It was leaking from just below the top left screw.










*EDIT 2:* The Blue Hylomar failed. Not only that but the coolant leaked out and into the previously dry motor, where it caused the brushes to burn out. When I connected 12V to the motor it barely turned and was getting warm at the brush end.

I decided to take the connector end cap off which holds the brushes. This can be done by bending back the metal fingers (formed from the case edge) from recesses in the cap. The cap can then be pulled out with a little manipulation.










The commutator and brushes were filthy with the splattered deposits of brush dust, dried coolant and burnt carbon. The brushes did not move freely due to the dirt and were not making good contact. The commutator was black and burnt with a greasy looking goo.

I almost gave up with the pump at this stage but seeing as the cost of a new one is well over £100 I decided to clean it. Sorry, I didn't take pictures of the following stages but it's a pretty standard brush motor design.

The brushes in the endcap could be cleaned with a toothbrush and solvent. I alternated with WD40 and then IPA. Finally, when dry and clean, the graphite brushes moved free and easy. I added a couple of drops of 3-in-1 oil to the phosphor bronze commutator shaft bearing bush.

The armature and motor casing were also filthy. I decided not to separate the magnetic cup at the other end of the armature, as it looked pressed on and I didn't want to risk damage. The magnetic material, being ceramic, is quite brittle. I cleaned up the inside of the casing walls with solvent, rag and scraper, trying not to get dirt between the armature and the magnets on the casing wall. I sprayed through with IPA (it comes out down the side of the manetic cup) and finished off with WD40 this time so the hidden bearing at the other end would at least see some oil and not be dried out with IPA. The excess was shaken out and dried with kitchen towel.

The commutator was cleaned bright with fine glass paper, a fibre glass pen and sprayed with switch cleaner.

Now the tricky bit: The brushes spring into the middle because there's no commutator for them to press against. This makes it difficult to get the end cap back on. What you need to do is wrap little loops of cotton around the brush tensioning springs and pull them back, holding them against the endcap edge with your fingers. With the brushes pushed back, the end cap can be replaced so the brushes are positioned in line with the commutator. Before the endcap traps the cotton against the case edge, the cotton can be released and pulled out. The brushes will then spring against the commutator but no further. The endcap can then be pushed fully home and the metal fingers bent into the recesses to lock it in place.










I tested the motor with 12V and it now spins at high speed and takes little current showing the friction is low 

This time I thought of two options. One was to throw away the O ring and use silicone sealant to replace it. This is problematic as it's messy and there is a chance the sealant may ooze out internally and gum up the turbine. It would conform to the flange distortion however. There is also the problem of silicone release: The sealant needs to cure fully (24 hours)and then be flushed through, before contact with coolant or there is a chance silicone molecules may be liberated into the coolant. This should be avoided as silicone, even in tiny traces, can damage lambda sensors and cause them to fail. This is more of a problem with silicone on sump gaskets but the potential is there.

I instead decided to improve the sealing face. I had noticed that when assembled, the O ring was hardly compressed before the flanges met. This would be due to flattening of the O ring but also distortion of the flange face. Indeed, holding the supposedly flat flange on a flat surface showed it to wobble when it should be firm.

Ideally the flange should be spun in a lathe. Not having one to hand I lapped both the motor and turbine housing face on Wet+Dry paper, lubricated with soapy water and lapped with an even circular movement on a flat surface.

The turbine housing was reduced further in order to squeeze the O ring more on assembly.










This gives a nice matte, even and flat finish.










It's important to clean, wipe and wash all dust and abrasive particles in particular, away.

When loosely assembled now, with the O ring in place, the flange faces are held apart by the O ring (about 0.75 mm), ensuring that the O ring will be forced to conform to any irregularities in the flange seal faces when the screws are tightened.










I tightened the screws after lubricating the turbine with a little petrolium jelly. Do not over-tighten or you may split the resin. I tested the pump with hot water and it pumped well at a high flow rate.

As a further test, I sealed the outlet with a rubber bung and filled the turbine cavity with IPA. I then held a foot pump into the inlet and pressure tested the pump to 40psi, whilst at the same time inspecting the flange seal for a leak. There was none. IPA is very thin and would show a leak better than water.

The pump is now back on the car and working successfully without any leaks. I think now, with the level of refurbishment, it should prove reliable.

*It is certainly worth checking the pump still rotates at high speed, from time to time, otherwise your turbo bearings may suffer if it stops. It should spin for about 10 minutes when the ignition is turned off.*

EDIT 3:

Doh! Famous last words :roll: It stopped again and this time blew a fuse, which also stopped the airconditioning from working, as this fuse also protected the clutch electromagnet on the compressor via the fan controller.

Unfortunately, when I took the pump apart the motor was too far gone to attempt another repair. One of the brushes had overheated and completely melted the plastic and was in a horrible mess.










I couldn't understand how it had leaked, given the improvements I had made to the O ring seating. Then I found out why. The thin plastic flange had cracked providing a leak path under the O ring.










If you see any of this cracking on yours I'd suggest doing away with the O ring and sealing with Silicone Rubber RTV gasket jointing compound to form a gasket, such as made by Hermetite. Also break off the loose parts of the plastic so there are no hairline cracks and the RTV can seal. If you do this, let the RTV cure for 24 hours and then pressure wash through with copious amounts of water to clean off any silicone residual contamination. Silicone can damage your lambda sensors if allowed to come into the engine, so better be safe than sorry. The cured silicone rubber is not a problem - only the traces given off whilst curing.

There was nothing for it this time but to buy a new motor. They are somewhat pricey however at around £80 from the Audi dealer. I tried GSF as an alternative but they only had one for a Golf at a reasonable £40 but it had a slightly different connector and as I found out a lower flow rate.

The one you want is this one. Bosch Part Number 0 392 020 039. Audi Part Number U078 965 561:










You may be able to get one for around £50 from eBay if you don't have a Bosch distributor near you.

https://www.google.co.uk/?gws_rd=ssl#q= ... h&tbm=shop

I managed to get a 15% discount at Audi which brought the bill down to around £70.


----------



## davidg (Sep 14, 2002)

[smiley=thumbsup.gif]


----------



## Toxic (Oct 16, 2005)

doctor will i need to clamp the arteries before i remove the organ?


----------



## John-H (Jul 13, 2005)

Has anyone got the machine that goes "Ping"?


----------



## John-H (Jul 13, 2005)

I've updated the repair procedure which should prove more reliable. It's worth checking the pump from time to time to see if it's still spinning fast and not leaking. It does look after your turbo bearings after all :wink:


----------



## WEALY (Feb 4, 2009)

Does the 180 have this pump?


----------



## John-H (Jul 13, 2005)

It was only on the 225 I believe.


----------



## pinky (May 21, 2009)

Iv just got the new Bosch part £88 all inclusive and going to fit it in a min.
Do I have to worry about air locks?
Thanks.


----------



## John-H (Jul 13, 2005)

No, it should sort itself out. You are only likely to trap a little air in the pipes to the run on pump, as if you plug the pipes or hold them high whilst swapping then you are not going to be loosing coolant and letting air in. Once the engine runs it should circulate coolant through the system and air will naturally migrate to the expansion tank. Even if there were some air trapped in the run on pump it would soon get pumped out once it started.


----------



## pinky (May 21, 2009)

Thanks John 

Also I have fitted it now but I can hear any noise coming from it..I checked the no16 fuse and it looks ok..maybe a little dirty.
Do they make much noise?


----------



## John-H (Jul 13, 2005)

They are pretty quiet but you should be able to hear a little buzzing and possibly the odd air bubble going past providing the background noise is low. In your quiet garage there should be no problem hearing it but next to a busy main road you've no chance. It's about as loud as the motor that operates your electric mirrors.

If you still can't hear it then there may be a problem with the connector contacts being corroded. Often when the pump leaks, coolant gets into the connector and corrodes the contacts. Give them a clean with a small jewler's screwdriver, being careful not to bend the spring loaded contacts slack. Test here for 12V too with a Volt meter. If 12V is not present test for each contact voltage to chassis ground and continuity into the loom. Hopefully some scraping or contact cleaner spray will sort it.


----------



## pinky (May 21, 2009)

Need to find somewhere quieter then...had some right noisy birds tweeting when I was trying to listen.
The two pipes that connect to it feel warm..but could that mean that water is just passing through..not pumped through?
Had a funny one this morning as I could see wet dripping of the lower grill bit and I thought that it was leaking from somewhere else...was
just about to stick my finger in it and smell it to see if it was coolant..when I noticed a yellow tinge...it was cats pee...lol must be a first for being happy that it was cats pee.


----------



## John-H (Jul 13, 2005)

I forgot to mention that the pump only operates immediately after you turn the ignition off. Just cycling the ignition on and off sets it going so you don't need to warm the engine up first or anything like that. It runs for aout 10 minutes. Sorry if you knew this already.


----------



## DAZTTC (May 20, 2005)

Hi John i think mine could be broken Hark brought his tester today and all we could get was something like 0.25v ish no signs of it leaking. :?

DAZ


----------



## John-H (Jul 13, 2005)

Hi Daz,

Sounds like you have a bad connection somewhere. One of the wires should be ground and the other +12V. I know someone had a bad earth connection and managed to fix the earth wire on his. Did you measure between the two contacts or did you measure each one to chassis too? The +12V line might be ok but you have a bad earth. It could be a problem anywhere back to the controller module however on the +12V line.

John


----------



## DAZTTC (May 20, 2005)

John-H said:


> Hi Daz,
> 
> Sounds like you have a bad connection somewhere. One of the wires should be ground and the other +12V. I know someone had a bad earth connection and managed to fix the earth wire on his. Did you measure between the two contacts or did you measure each one to chassis too? The +12V line might be ok but you have a bad earth. It could be a problem anywhere back to the controller module however on the +12V line.
> 
> John


Measured between the two  will check again where's the controller module ?

DAZ


----------



## John-H (Jul 13, 2005)

It's low down at the front by the radiator on the driver's side I seem to remember - you'll see it has a number of electrical connectors going to it.


----------



## DAZTTC (May 20, 2005)

Thank John I've just got the front bumper back on so can't see it now :x I got my self a tester from Maplins  i still only got 0.27 then it was jumping up to 4.36 5.54 1.25 and back to 0.27:? so i gave in reconnected and packed up so i thought I'll give it one more tern of the key of and out and look up. The pump springs to life runs for about 10 minutes   tried it again and nothing. :x so i guess it must be the pump I'll get a new one. :roll: 
Edit Spoke to Ed at APS he thinks it could be a bad earth so i need to remove the front bumper again. [smiley=bigcry.gif] John do you think as you've said it will be in the control module ?

DAZ 8)


----------



## DAZTTC (May 20, 2005)

OK update been back out to the car open ignition on off it works and runs for 10mins Wylie it was running i disconnected the plug to test for volts its 12.79v  
10mins gone buy try again tern key and the pump starts again :? started car pump is still running.tern off no pump :? 
key out back in ignition on and no pump :?

John do you think there is some sort of time delay on this pump/controller module ???

I will leave it 1hr and go back out and try again at 6pm see if it works.If it dose will leave for another hour then pop out for a drive then see if it will work when i tern off??? we will see :roll: hope so.

DAZ 8)


----------



## DAZTTC (May 20, 2005)

Been out to the car ignition on can here pump running ignition off it still runs  next update in a bit when I've been out for a drive :wink:

DAZ


----------



## Hark (Aug 23, 2007)

DAZTTC said:


> Been out to the car ignition on can here pump running ignition off it still runs  next update in a bit when I've been out for a drive :wink:
> 
> DAZ


So what did you do to get it running? Listened to mine tonight, you should hear a buzzing shouldn't you?

Couldn't hear anything so mines playing up.


----------



## John-H (Jul 13, 2005)

Sounds like a bad connection - especially as you measured the connector and got erratic readings - so that's nothing to do with the disconnected pump! - so don't buy a new pump if this is the case as the fault is in the loom or controller.

I've just checked the wiring diagram and the pump is earthed to an earth connection that is common to the fans and controller module in the aircon loom. I'm not sure where this point is exactly but they are often a wire that comes out of the loom with a ring tag on it that is bolted to the chassis somewhere nearby.

It could be this ring that is making a bad connection (in which case all your fans wouldn't work) but as it earths a number of items, there is likely to be a crimp connection within the loom to which a number of wires wanting to be earthed are connected. The bad connection could be at this crimp and only be affecting your pump's earth wire.

Alternatively the wire could be part severed somewhere along the run back to the pump connector, or there's a corroded contact at the connector crimp or the spring contacts of that crimp contact where it connects to the pump.

Of course, you could have a similar bad connection on the +12V side of the connector anywhere all the way back to the controller. In fact fuse 16 could be loose, prior to the controller but your aircon magnetic clutch would be disconnected by a fault here.

*Diagnosis:*

With the pump activated (ignition cycled) if you are getting jumping readings across the pump's connector, keep the positive conncection connected here and connect the other meter lead to chassis - if it's now a solid +12V then you have a bad earth in the loom. If your tester measures Resistance (Ohms) then you could check between the earth wire at the pump connector and chassis for a short circuit. You can poke a sharp pin into the wire insulation, an inch behind the connector, to connect to the wire within. If the earth is good at this point then you know the fault is in the connector. If it's still bad you can keep probing with the pin all the way back to the common earth connection.

By the way, the manual says the control module is on the left side of the car but I'm not sure if that's because it's a LHD manual or if I was upside down when I saw it :roll:


----------



## ttpanos (Nov 8, 2009)

my  ,187 euro only pump ,from audi .


----------



## DAZTTC (May 20, 2005)

Hi John thanks very much for your help think i got it now i will check all the above and back to the J293 which is behind the front bumper passengers side between the number plate and the head light. The ground is number 2 sw=black bl=blue 
should be T10-connector 10 pin and T22a- 14 pin 
I assume the wires from the pump connector go into the headlight wiring harness then back out and to the J293.OOH get me
i almost sound like i no what i am doing. :lol: :wink:

Thanks again mate. [smiley=thumbsup.gif]

DAZ 8)


----------



## DAZTTC (May 20, 2005)

Tested from the run-on pump connector all the way back to the connector on the fan control module J293 ( part number 1J0919506k ) The wires are fine put every thing back and the pump will only run when its been left for a bit. But still will not run when engine has been terned off  So i think my pump is fine I'm going to get a new J293.

FYI the J293 is located under and to the left of the battery take the battery and tray out undo the two 10mm nuts that share the map sensor pipe bracket and the Module is free.

DAZ


----------



## pinky (May 21, 2009)

Finally have a working run on water pump...and my fans are now kicking in when in traffic...
all it was was the 30amp fuse nearest the engine on top of the battery cover 
Noticed that my aircon didnt get cold either..so its all linked.
Soooooo happy to hear that lovely little hum


----------

