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How-to: Ian Frechette's detailed guide to replacing the main coolant pump

Table of Contents
Detailed Guide to changing the water pump. (Mk3 VR6) Ian Frechette <frechett@rintintin.colorado> Fri, 27 Jul 2001 00:53:19 -0600
Re: Ian Frechette <frechett@rintintin.colorado> Tue, 06 May 2003 02:33:49 -0600

From: Ian Frechette <frechett@rintintin.colorado>
To: list@gti-vr6, VW-VR6@onelist
Subject: Detailed Guide to changing the water pump. (Mk3 VR6)
Date: Fri, 27 Jul 2001 00:53:19 -0600
My water pump pulley shaft was very slightly bent causing the pulley
to wobble which led to to a number of problems
with broken belts and pulleys and so forth with my non-springloaded
supercharger belt tensioner.   (Not spring loaded so it can't handle any
rapid changes in belt tension, such as that induced by a wobbly pulley).

Anyway.. I changed the water pump tonight.
Here's the process with some tips and tricks I've learned.

Tools you'll need or will be useful. 
- 12mm box/end wrench  (for exhaust downpipe nuts) 
- 13mm box/end wrench  (for downpipe bolts and bracket nut above motor mount)
- 17mm shallow socket  (driver side rear motor mount)
- 16mm deep socket     (passenger side rear motor mount)
- Two long 3/8" socket extensions .  This usually requires buying two
  normal sets of 4 extensions so get *one* of the sets with the wobbly end
  drivers.  This lets it drive the socket off angle which will be useful.
- 8 mm allen wrench    (front motor mount)
- 6 mm allen wrench    (water pump pulley bolt, and water pump bolts)
- 6 mm allen socket drive (can probably do without, but it's REAL handy
                           given the number of 6mm allen bolts we have)
- 8x80 metric bolt  (for the belt tensioner)  
- 2 jack stands
- 1 floor jack plus a short length of 2x4
- Crowbar and hammer.   (for loosening the old water pump)
- A good work light.. 
- A big wide pan, like one of those oil drain pans with a spout to
  catch the coolant when it gushes out.
- A gallon of G12 coolant (ouch this shit is expensive)
- A gallon of distilled water 
- WD-40 for the downpipe to cat bolts/nuts
- 3/8 inch torque wrench is useful, but folks have been known to
  wing it.  ;)

Steps (Note, with the right tools anyone can do this.)  Promise.

1. Park the car for a day so its cool.  Makes it easier
   to deal with exhaust and coolant and everything.

2. Put the car up on jackstands, so you've got enough room to
   crawl around under there to get to the cat.     Easiest from
   the front.

3. Spray the nuts that connect the exhaust header downpipe to the cat
   with WD-40 and let them soak for a while..   They're always rusty.  
   *Always*  If you try to break them loose without WD

4. Crawl under there and disconnect the cat from the downpipe.
   I usually find that I can loosen the nuts on the bottom two bolts
   but have to switch to loosening the bolt for the top one.

5. Remove airbox.. (There are instructions elsewhere for this.)
   I don't have one so this is simple for me.   If you want you can
   pull the intake tubing off the throttle body too as it'll
   open up the area to the rear motor mount, but it's not necessary if
   you've got the extensions I told you to get.

6. Remove the hex bolt for the front motor mount with an 8mm allen wrench.

7. Remove the 13mm nut from the top of the passenger side back 
   motor mount.  It just holds a little bracket on.  Stuff the bracket
   and trailing wires in the corner out of the way.

8. From your two sets of extensions (usually 4 extensions in each set)
   hook together a bunch of the intermediate lengths, and stick the
   deep socket 16mm on the end.  (2 3/4 lengths and 2 half is about right)
   Feed it down to the passenger motor mount bolt and take it out.
   It's *soooo* nice to work with the extensions  so that your socket
   driver is about even with the rain gutter instead of busting
   your knuckles way down below the intake.. 

9. Hook up the two long extensions with the wobbly end one at the bottom.
   Stand by the driver side fender, feed the 17mm shallow socket down
   underneath the coolant resevoir and ABS brake lines and stick it on
   the driver side motor mount bolt with your left hand, and keep your
   hand there.   With your right hand stick the extensions down as close
   to the coolant resevoir and firewall as you can get and feed it down
   and through the brake lines.  You'll find that it slips between two
   of the 4 brake lines and hits the socket at an angle.  That's what
   the wobbly end is for.  It'll snap right into place.    Remove the
   driver side motor mount bolt.   Leave the socket and extensions in
   place.   This is why I end up with two super long extension sets.  The
   driver side is such a pain normally, I just leave the extension and
   socket there while I work on the engine.

10. Place the 2x4 on top of the floor jack, and against the passenger
   side of the oil pan.   

11. Jack vigorously.  The passenger side of the engine should raise
   quite a ways up (like 5-6 inches).  The water pump pulley bolts should
   all clear easily.

12.  Use your 6mm socket drive allen wrench if you got it (or
   good quality regular allen with an extension handle) 
   and loosen the water pump pulley bolts with the belt still
   under tension.

13.  Put the 8x80 bolt into the hole in the top of the stock belt
   tensioner and screw it in until you've relieved the tension
   on the belt, and then some.   The belt should clear the 
   tensioner pulley easily.

14. Remove the belt from all the pulleys but the main drive pulley
   and simply shove it into the little gap to the left in front
   of the drive pulley.

15. Remove the water pump pulley bolts (they should come off by hand
   at this point).

16. Now you'll see the water pump bolts.  You should be able to jack
   the engine up another inch or so to clear the bottom water pump
  bolt but if you really aren't comfortable jacking further then
  use your regular 6mm allen and and handle extension for the bottom
  bolt.   Remove the 3 bolts.  (Again the 6mm socket drive allen is
  awfully useful here)

17.  Put your oil drain pan under the car.  Try to get as much of it
  under the water pump area as possible.     The coolant will go

18.  My water pump was frozen in place by general gumminess, so it
  took some work to break it loose from the block.  Hook the crowbar
  on the little tab at the top of the water pump and pry against
  the block.  It should eventually come out an 1/8th inch or so 
  at the top..   Use the hammer to knock it back all the way in.
  Pry again until it stops.. hammer back.. etc..   Each time it'll
  come out further (about 3 times), and finally loosen completely.

STOP STOP!! Don't pull the pump out yet.
The next step is messy, and we're trying to save some coolant. 

19.  Get your new water pump ready.  Be sure it has a new O-ring on
  and it's within arm's reach.
  My pump from Potterman came with it, as it should.

20.  Get a rag ready.. Pull the old pump out just far enough to
  get your finger and the rag under the edge between pump flange
  and engine block.  It'll start drooling
  coolant everywhere.  Wipe down as much of the edge where the O ring
  sits as you can. Try to get off all the dirt, and gumminess and oil
  and stuff. 

21.  Get the new pump ready.  Pull the old pump out and while it's gushing
  coolant all over, wipe the bottom of the opening with the rag and then
  quickly slide the new pump back in place.   You'll probably have lost
  at least a gallon of coolant by this time.  No real cure for it.

22.  Ok, now that the gushing has stopped and the new pump is in,
  Reverse the process.  Put the water pump bolts back in, torque 
  to 15 ft-lbs (it's really not much).     Put the water pump pulley back
  on, and hand tighten bolts.   Re-install belt.  As long as you
  didn't take it off the drive pulley it should go back on really
  quickly.  Make sure it's lined up on all the pulleys and loosen
  the 8x80 bolt on the belt tensioner to bring the tension back on.
  Now go back and torque the water pump pulley bolts now that
  you have some tension on it.  Torque to 18 ft-lbs.  You may still need
  to stick a screwdriver in one of the 3 holes in the pulley to
  keep it from slipping when you tighten the bolts.

23. Lower the engine back down slowly until it hits the rear passenger
  motor mount and then stop.  Jack it back up a quarter inch or so
  to relieve some of the weight on the mount.   Shine a light down the
  passenger motor mount hole and see where you'll need to move the engine to
  line it back up.  Give the engine a good shove in the right direction and
  keep checking the hole.  When it's close, drop the motor mount bolt
  back into the hole, and then wiggle (lots of grunts and groans) 
  the engine around until the bolt drops down into the hole below
  when it lines up.  
  If it's not moving much, then try jacking it up another 1/4 inch.

24.  Tighten the passenger side engine mount bolt.. Don't forget to
  take the jack out after the bolt is started.   Tighten to 44 ft-lbs.
  Reinstall bracket with 13mm nut on top of engine mount bolt.

25. Put driver side engine mount bolt back in place.  I find that
  this one always lines itself up just fine.  This is where you'll
  find that long wobbly end extension handy again.  Tighten bolt
  to 44 ft-lbs.

26. Put front motor mount allen bolt back in.  Tighten to 41 ft-lbs.

27. Crawl under the car and reinstall the gasket and 3 bolts between
  downpipe and cat (supposed to use new bolts, but if you loosened them with 
  WD-40 originaly, they should be usable again).   Bently says to tighten
  these nuts to  either 18ft-lbs (for M8 nuts) or 30 ft-lbs (for M10 nuts).
  I don't know which one they are.   24ft-lbs.. ;)

29. Re-install the airbox..

STOP!!! Don't forget your coolant is all gone.

30. Refill the coolant resevoir with a mix of 50% G12 (or G11 if appropriate)
  and 50% distilled water.  You'll find it disappears fairly quickly.  I
  recomend doing it a 1/4 or 3rd of a bottle at a time and alternating.
  When it's between MIN and MAX, start the car up and let it idle for a 
  minute.  Stop.  Check the level, and bring it back up to somewhere between
  MIN and MAX. What's cute is that sometimes it shows color and sometime it
  shows clear.  It'll take a while for the water and coolant to mix.  
  Bently says the level should be at MAX when at operating temperature
  and somewhere beteen min and max when cool.

31. Might as well start it at this point while it's still on jack stands 
  in case you forgot something..  It'll probably squeak some at first
  because the belt and pulleys probably have some coolant on them.  It'll
  go away soon enough.  Make sure everything is working, and pump is not
  leaking or wobbling, and everything's hooked back up and working.. 

32. stop the car and take it off the jack stands.

33. If you've emptied your G21 bottle or distilled water bottle
  pour your dead coolant back into those.  

Be sure to drive your car around some and check the coolant level.
It should range between halfway between MIN and MAX and MAX when hot.


It sounds like a lot, but it only took me about 2 hours.  I've had to jack
the engine up a few times before when dealing with the supercharger so 
that's why I know that some of the tricks with engine mounts and 
long socket extensions will save A LOT of time.  The extensions are
cheap anyway.

Most of tools you should already have, and the couple special ones
like 6mm socket drive allen, 16mm deep socket and 2 extension sets
will come in useful for other stuff.  

This may also be a good time to change your serptentine belt, and/or
water pump pulley itself (it does wear some).   Be sure to lower
the engine back down about halfway if you're going to install
the new belt.  It won't clear otherwise.


From: Ian Frechette <frechett@rintintin.colorado>
To: list@gti-vr6
Subject: Re:
Date: Tue, 06 May 2003 02:33:49 -0600
Matthew &lt;&#99;herrypop&#64;mac<img src=/i/dc.gif border=0 width=35 height=15>&gt; wrote:

>Hi.  I read your post to regarding the detailed guide 
>to changing the water pump on a VR6.  Thanks for taking the time to 
>post those instructions.
>I have a 1997 Jetta GLX (91k) with a bad pump and wondered if you've 
>revised the guide with any additional information since 2001, or if it 
>is more or less the same.

It's more or less the same, except that I don't bother to
detach the downpipe from the exhaust pipe any more.  Just 
remove front lower engine mount bolt, loosen to rears and raise the front 
of the engine carefully until you can get to the water pump.

I can't stress enough how convenient it is to have the proper 
long socket extensions for getting to the rear motor mount
bolts from the top.  


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