aux water pump buzzing

[LukeManic 0]

Hi guys,

 

Just got in from work - was stuck in heavy traffic and the VR got hot, fans came in fine and she never went over 100c, put her in the garage and just before I turned the engine off I noticed a LOUD buzzing from the engine. I turned ignition off and the buzzing stopped - turned the ignition so only the dash lights would come on and the buzzing noise came back. Its never made this loud buzzing noise before - I understand the pump should make some degree of noise. Does this need replacing?

 

Also, as soon as I take the key out of the igintion the pump cannot be heard at all. Is this the way it should be?

 

Thanks in advanced.

[Supercharged 2]

Probably on it's way out tbh... best get a replacement before your heater matrix explodes!

[LukeManic 0]

Thanks for your input.

 

Can people confirm to me what is true here (been doing some research):

 

If I turn my iginition on the aux water pump can be heard, now some people are suggesting that it should also stay on for 10mins after the key has been taken out of the iginition regardless of whether it is hot or cold??? this true?

 

Mine doesn't stay on at all when the key is out - only comes on when the iginition is turn on.

 

Thanks in advanced.

[dinkus 10]

I was under the impression that it was only supposed to run-on if the water was hot.

 

Either way, if it's making a rattly grindy noise then it's time for a new one and they're not cheap :(

[Roger Blassberg 0]

As I understand it, the pump runs at all times that the ignition is on, and also together with the fans after a hot run with the ignition off. The pump normally makes a whirring sound and you can feel it vibrating if you touch it. It's reasonably easy to change, costs about £60. There are 2 different electrical connector shapes available, so make sure you get the right one or be prepared for a bit of amateur electrician work to splice a connector into the loom.

 

Best wishes

 

RB

[LukeManic 0]

Thanks for the anwers guys.

 

As for changing it myself, I've been looking how I will get to it and can see the plastic engine cover covers the pump's connectors, am I right in thinking I need to take the engine cover off to gain access to it? Also how is the pump held? Any help on this is much appriecated.

[Roger Blassberg 0]

Yes, you need to take off the plastic HT lead guide(s) which are held on with Torix screws. The pump is supported by rubber mounts (which may be perished) and the hoses themselves; it will become obvious as you progress. As I said before, make sure the electrical connector is compatible before you strip the pump off the hoses. And have a bottle of G12+ handy to top up the coolant afterwards.

 

Obviously you need to pull the plug leads off, so you'll need the special tool for that or risk damaging them.

 

Best wishes

 

RB

[LukeManic 0]

Again, thanks for answering.

 

Can I not just unplug the leads from the coil pack? Does this also require a special tool to do this?

 

Thanks in advance.

[flyferrari 0]

Hi,

 

I looked at doing this job as the next step in diagnosing my hot running problems (see my thread on this). The pump is £94 inc VAT from VW. The ones from ECP are cheaper but not enough to cover postage/possible grief from getting the wrong one. Unplug ignition leads from coilpack/dizzy noting which lead goes where.....I took several digital photos just in case!! They come off with fingers...no special tool required....any lay the ends out of the way. Remove the end piece of trim plastic.....its held on with three 8mm Spline drive screws (you might get away with a torx screwdriver but for a few quid for the right tool why risk it). You now have access to the pump. The hose connections are at the bottom and are held on with spring clamps. Once again the correct tool will make removal easy rather than risk broken parts/skinned knuckles using normal pliers. The pump is held on with two rubber supports(not included with the pump!) One of mine was b******d. After fitting refill and bleed the cooling system as described in the Bentley manual. Not especially difficult job.

 

Regards

 

Kevin

[LukeManic 0]

Kevin, your a star mate - very helpful, thank you. Thanks to all previous posters too, much appreciated.

[craigowl 0]

I did this job OK last August on my 1995 VR6 and I am no wizard mechanic. I got new pump from ecp for £68.15 incl VAT

 

Their part no is 201440740 - it is a Bosch.

 

Will look for more info.

 

PS I can confirm you only need unplug leads from coilpack end - no special tool involved.

Also, you can get enough coolant out of system by letting it flow out of coolant hoses attached to pump - no need to empty all coolant from bottom of engine.

[Kevin Bacon 5]

If I turn my iginition on the aux water pump can be heard, now some people are suggesting that it should also stay on for 10mins after the key has been taken out of the iginition regardless of whether it is hot or cold??? this true?

 

Yes.

 

It's ~ 10 mins, I haven't timed it with a stop watch yet :lol:

 

The VR cooling system really is not that complex but so many people seem to struggle with it.

 

I'll try and break the whole thing down into as few sentences as possible!

 

The 'heart' of the cooling system is the controller bolted to the nearside turret. It's a sealed box with a timer, relays and fuses. It's not DIY repairable and costs £120. They do pack up from time to time.

 

When it receives an ignition signal, the water pump is switched on (and stays on) and fan speeds 2 and 3 are available. Fan speed 1 is independant of the controller, and fan 2 can also operate if need be via the controller for up to ~ 10 mins after power down. Fan 3 is ignition ONLY and the black sender in the stat housing controls it. Fan 1 and 2 run from the sender in the radiator.

 

Fan 1 activatation temp - 90 deg. Slow.

 

Fan 2 activatation temp - 100 deg. Normal.

 

Fan 3 activatation temp - ~ 120 deg. Fast (very!).

 

Fan 1 and 2 will be working when sat in traffic, but mostly Fan 1. Fan 3 should NEVER come on under normal conditions. It's an emergency reserve and is twice as fast as Fan 2 and shifts LOTS of air. If it does come on, you have problems, but it's very useful to operate manually for hot summer days. You just need a length of wire and a switch on the dash.

 

When the ignition is turned off, the controller timer kicks in and maintains power to the aux pump. Why? Because the rear bank of 3 run very hot. When you power down the engine all the heat from the exhaust manifold soaks back into the head. The aux pump maintains flow round the block and through the heater matrix to prevent localised over heating. After around 10 mins, the aux pump powers down and power to Fan 2 is cut. Fan 1 can still work if necessary.

 

And that's it, in a rather big nutshell.

 

My opinion of the system is it's one big pile of over engineered and expensive tat. Fan 3 can be very useful if manually operated, but tbh, I have dumped all of it and I just run one 11" slimline fan triggered from the rad sender and the water temp never goes over 95.... not even when stuck in traffic for 2 hours.

 

I see many posts about folk fretting over VR running temperatures and the aux pump etc. Do yourselves a favour and ditch the whole lot. You'll thank me for it :lol:

[herisites 0]

Hmmm i used to get a loud buzzing noise just as you have described but it went away and hasnt done it for ages ... BUT my heater matrix blew the other day so im guessin thats probably why?

 

So i guess i should change my water pump as well as fit a new heater matrix (not looking forward to that!!)?

 

I didnt know it was the water pump buzzing as i always thought the water pump ran off the pullies etc down the side of the engine? Or am i being thick? :lol:

[Toad 0]

Sorry Kev, but I disagree. The controller unit is diyable, as I've done it... A common fault appears to be when the diodes on the switched ignition circuit become unsoldered from the pcb and rattle about, stopping the pump from running. You can open up the box and resolder them.

 

I did a thread on this a while back.

 

As far as the 10 minute afterrun. Some VR6s do after run for 10 minutes, some only after run while the fan is going. Think the later units only run with the fan.

 

My pump makes a hell of a racket, and is noisier inside the car than under the bonnet strangely... I'm going to wait for it to pack up completely before replacing it. These also can be DIYed, if you know what you are doing.

 

Edit, Herisites. There's amanual waterpump driven by the belts, and an electric unit next to your coilpack. one of the hoses from the matrix is plumbed to it.

 

If it has failed it could contribute to your matrix going, but I'd expect to see higher temperatures leading to greater pressure leading to matrix going pop. I assume that you haven't...

 

A lot of these components are just reaching the end of their servicable lives.

[craigowl 0]

If your pump has seized, herisites, you may need to replace its 5amp fuse, too, when you do the work.

It is situated in module in pic.

[herisites 0]

Edit, Herisites. There's amanual waterpump driven by the belts, and an electric unit next to your coilpack. one of the hoses from the matrix is plumbed to it.

 

If it has failed it could contribute to your matrix going, but I'd expect to see higher temperatures leading to greater pressure leading to matrix going pop. I assume that you haven't...

 

A lot of these components are just reaching the end of their servicable lives.

 

Ahh so im not being thick then :lol:

 

My water temps have never been high, i dont think i have ever seen it go above 110 degrees and thats when its really hot, general fast driving etc doesnt really go above 100 degrees. So do you think my matrix just went because its 12 years old then? I dont want to fit the new one and it goes again a few months down the line because something else isnt working properly!

 

Like i said though my aux pump hasnt made any noise for a good few months now, so does that mean its ok or should i think about replacing it?

[herisites 0]

If your pump has seized, herisites, you may need to replace its 5amp fuse, too, when you do the work.

It is situated in module in pic.

 

How would i know if the pump has seized? It hasnt buzzed for ages so i assumed everything was ok? Should i check the fuse anyway?

[Supercharged 2]

Thats actually a 30 or a 50amp fuse that big one depending on air con or not...

 

Only available in packs but I have some 50's if anyone needs one...

[craigowl 0]

Lukemanic

Here is some edited text and pics from write up I did last year.

Hope it helps.

 

I replaced auxiliary (electric) water pump on VR6 a couple of days ago.

Pump price to nearest £, including VAT:

Quote from VAG Advantage, Stirling – £93, but, when asked, he kindly offered about 10% discount if you can produce CCGB card.

 

Bought from ECP (Edinburgh) - £68 including CCGB discount on showing card. – identical to original Bosch unit.

 

 

After installing new pump, I took old one apart - it was seized - both the impeller and the electric motor.

 

You will possibly not know it is seized, because, from my experience, the car still runs OK and I had no overheating or coolant loss problems. Consequently, I would recommend those with VR6s check the pump’s 5 amp fuse, you will mostly not know if it has failed, except by visually examining it.

 

CAUTION - BE SURE THE RADIATOR FAN IS DISCONNECTED FROM THE POWER WHEN DOING THE FOLLOWING, IN CASE YOU MAKE A MISTAKE - IT STARTS SUDDENLY AND YOU DO NOT WANT YOUR BITS CAUGHT UP IN IT.

 

Tested in isolation, a new pump does make a slight running noise but if fans are on they drown it out.

 

I found you can listen to the aux pump in isolation by disconnecting the power supply plug to the (Bosch) radiator fan and linking the two appropriate terminals on the yellow coolant temperature sender as described in both the Bentley and the Peter Russek books. (I used a small U-shaped staple to bridge the brown wire’s terminal and the one diagonally across from it, i.e. the two terminals you are told to bridge in the books.)

 

By the way, I found there is no need to drain all the coolant from, say, the bottom hose connection (really awkward for me) or the “official” drain plug (can crumble, I believe!)- I merely drained coolant from a very accessible hose half way up the engine. (see pic)

 

………shows the extension I fitted to a cordless power drill (9.6v) to retighten the hose clips after refitting the two hoses to the new pump and the one from which I had drained about half of the coolant. After a lot of frustration, I found this to be a far easier task using this arrangement, compared to trying to screw up the hoses using an ordinary screwdriver. Wish I had thought of it years ago. I used a torque setting of 2, cautiously followed by 3.

[herisites 0]

craigowl - did you do a full write up on how to change it? If so do you have the link?

[C. Will Corrado G60 2 0]

herisites

 

My pump also made a lot of noise for a while then stopped. I imagine this has failed after reading this thread. I haven't noticed any over heating but do you think I should change this anyway?

 

C

[Kevin Bacon 5]

Sorry Kev, but I disagree. The controller unit is diyable, as I've done it... A common fault appears to be when the diodes on the switched ignition circuit become unsoldered from the pcb and rattle about, stopping the pump from running. You can open up the box and resolder them.I did a thread on this a while back.

 

Didn't see that thread, but how many people on here feel confident cutting open the controller (to remove the silcon bonded lid) and soldering diodes? That's why I said it wasn't DIYable. Maybe I should have worded it slightly differently.

 

As far as the 10 minute afterrun. Some VR6s do after run for 10 minutes, some only after run while the fan is going. Think the later units only run with the fan.

 

They should all do it. VW only have 1 part number for the fan controller which covers all Corrados and Golf VR6s.

As I said, Fan 1 is independant of the Controller as it's direct to battery via the thermoswitch. Fan 2 has it's positive current retained during the after run stage and if the rad thermoswitch is hot enough, it provides the negative switching and will also work. The pump runs regardless and is not 'triggered' by the fans, it's coincidental. If the water is less than 90 deg on switch off, the fans won't come on but the pump does.

 

If a VR differentiates from this, then it's not working as VW intended.

[Toad 0]

Sorry Kev, but I disagree. The controller unit is diyable, as I've done it... A common fault appears to be when the diodes on the switched ignition circuit become unsoldered from the pcb and rattle about, stopping the pump from running. You can open up the box and resolder them.I did a thread on this a while back.

 

Didn't see that thread, but how many people on here feel confident cutting open the controller (to remove the silcon bonded lid) and soldering diodes? That's why I said it wasn't DIYable. Maybe I should have worded it slightly differently.

 

If it's not working, then there's nothing to lose by opening it up (carefully) and having a crack with the soldering iron really.

 

It's a large component so even fat fingered people (like me) can sort it out. The only problem is wchich way round they fit, but I'll reopen mine and get some pics not I know it works.. as for the sealant, it's just a miniscule scrape of silicon round the edge. The awkward part is unclipping 3 edges at once to slide the lid off.

[plateletboy 0]

I've always been a bit confused as to whether the aux pump is supposed to 10 min over run or not...

 

Mine doesn't, but everything else does what it should... So i was looking into this and an american forum thread claimed that there were 2 types of control module, one that over runs, and one that doesn't..?!? I guess it could have been a VW USA thing at the time, and since then VW phased out the controllers to just one part number that we see in the UK??!? Has anybody else heard this..?!?

 

At the moment i'm not ready to spend £120 to check if the lack of over run is the module or not, so if its been thrashed i let it idle for a bit until i switch it off.......

 

pb

[Kevin Bacon 5]

When I replaced my controller, the stealer said there was only one type, so I just bought that. Maybe other countries had variations as you say. Maybe cold climates don't need the after run?.....or my dealer lied to me :-)

 

Put it this way. My original controller gave me grief with fan control and it also didn't run the pump on shutdown, but did with the ignition on. I replaced the controller, then every thing worked perfectly. In my mind, the afterun circuit has to work on shut down as that is the main reason for having the extra pump in the first place, although it does flow quite well for such a small unit, so is an 'assistant' to the main pump too. I have heard of people removing the aux pump with no ill effects though.

 

Unless VW 'changed' the design of the controller over the years, I would say if the pump isn't running on shutdown, something is defo wrong.

 

Toad - Useful info cheers. I didn't attempt to open mine but glad you did and discovered it's servicable.