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VW / Audi Water Pump Replacement
 
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Pelican Technical Article:

VW / Audi Water Pump Replacement

Peter Bodensteiner

Time:

4 hours4 hrs

Tab:

$50

Talent:

*****

Tools:

All of them

Applicable Models:

 
Audi A4 (1997-01)
Audi A4 Quattro (1997-01)
Audi TT (2000-04)
Audi TT Quattro (2000-04)
VW Beetle (1999-02)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Passat (1996-00)

Parts Required:

New water pump

Hot Tip:

Patience!

Performance Gain:

Engine cools again

Complementary Modification:

Replace radiator hoses

Ah, the water pump. In a water-cooled car, it is critical to the health of the engine, as it is responsible for circulating coolant through the engine, as well as the radiator and heater core.

It's a simple part, really. In our 1.8T Audi engine, the crankshaft is equipped with a pulley that is connected via the ribbed serpentine belt to the power steering pump. In turn, the power steering pump is connected by a smaller belt to the pulley for the water pump. The pulley is connected to an impeller, a fan-like turbine that is the single moving part of the water pump, which is what moves the coolant.

With Audis and Volkswagens, mechanics almost always recommend changing the water pump at the same time as the timing belt (it's also convenient to do in concert with an alternator replacement or accessory belt replacement). Two primary reasons for this: 1) it's convenient to change the water pump when the radiator support is already in the service position and you're working on the front of the engine; 2) for a number of years Volkswagen and Audi used plastic impellers, rather than metal ones. These plastic impellers were prone to failure, which would lead to engine overheating. This exact failure happened to my wife's 2000 Jetta, which had the 2.0L, non-turbo engine. Only her quick actions, and/or the fact that the 2.0 was built like a tank, saved the engine from serious damage.

Your engine may or may not have a plastic impeller, but the water pump is relatively inexpensive to replace, and if you're "in there anyway," you might as well install a new one. Overheating is a good way to ruin an engine quickly.

There are two ways to go with this: replace only the impeller side of the pump--meaning you can leave the water pump housing in place on the engine and just replace the "face" of the unit--or replace the pump and housing as an entire, single unit. You can buy the replacement pump in either configuration.

If you decide to replace only the pump side, you'll need to remove the intermediate shaft pulley in order to gain access to some of the bolts that hold the pump in place. You'll also need to install a new gasket and sealant when you install the new pump.

If you replace both the pump and housing, you first need to remove the large brace that sits on top of the water pump and provides mounts for the power steering pump, alternator, and engine fan (I'll call it the alternator bracket to simplify identification). You will also need to loosen some support brackets and two coolant hoses that attach to the housing.

I would say that replacing the housing and pump is the more involved of the two options. In my case I replaced both, as I already had the alternator out, and because of my desire to be of service to you, valued reader! In the end, though either job is pretty straightforward. If you're able to disassemble the pulleys and belts of your engine enough to get to the water pump, you are qualified to replace the pump itself.

I also cover replacing the thermostat in this project. This can be done without moving the radiator support panel into the service position, or removing any part of the water pump. I replaced the thermostat while the pump was on the bench, but it's easily accessible under the car simply by removing the plastic undershield.

Before starting this project you should make sure the engine is cool and that you have drained the coolant (see the project on draining and flushing your cooling system). You should also place the radiator support panel in the service position, remove the serpentine and water pump belts, and remove the crank pulley and the lower timing belt cover, part of the timing belt replacement procedure.

If you are removing the water pump and its housing, you may be able to leave the alternator attached to the bracket to which it is mounted, but the electrical connections will limit its movement. In the photos below the alternator has been removed. It's also helpful to remove the intake hose between the intercooler and the throttle body, as it will give you much more room to work, plus it's easy to do.

If you have decided to replace only the face of your water pump, as opposed to the whole thing, housing included, you'll need to remove this pulley to gain access to three bolts hidden behind it.
Figure 1

If you have decided to replace only the "face" of your water pump, as opposed to the whole thing, housing included, you'll need to remove this pulley to gain access to three bolts hidden behind it. One of these bolts is just visible through a hole in the pulley, and two of the other bolts holding the face of the water pump are also visible. The stud in the upper right is one of the spots where the lower timing belt cover is secured with a 10mm nut--it's actually a hammer-head bolt that you'll have to take care not to misplace.

If you only need to replace the thermostat, you're in luck, as you don't need to do much to gain access other than getting underneath the car.
Figure 2

If you only need to replace the thermostat, you're in luck, as you don't need to do much to gain access other than getting underneath the car. From there, this is the view you'll see, with the thermostat housing mounted to the underside of the water pump, right next to the drain plug.

I elected to remove the water hose leading away from the thermostat because I was going to be removing the whole water pump anyway, but you could simply unbolt the housing, leaving the thermostat housing and the hose together.
Figure 3

I elected to remove the water hose leading away from the thermostat because I was going to be removing the whole water pump anyway, but you could simply unbolt the housing, leaving the thermostat housing and the hose together.

Even if you've drained the cooling system through the radiator and water pump drains, some coolant will spill out when you detach this hose, so have a pan ready.
Figure 4

Even if you've drained the cooling system through the radiator and water pump drains, some coolant will spill out when you detach this hose, so have a pan ready.

In order to remove alternator bracket, you must first remove some smaller supports that attach to it.
Figure 5

In order to remove alternator bracket, you must first remove some smaller supports that attach to it. Loosen the lower bolt of this support for the intake manifold using a 6mm Allen-head socket.

Once you've removed this bolt you can pivot the support out of the way.
Figure 6

Once you've removed this bolt you can pivot the support out of the way. I reinserted the bolt so that I wouldn't lose track of it.

Just inboard of this support is another brace, this time running between the alternator bracket and the engine block.
Figure 7

Just inboard of this support is another brace, this time running between the alternator bracket and the engine block. Use a 8mm Allen-head socket to remove the bolt on the alternator-bracket side...

The third and last support you have to worry about is this one next to the power steering pulley.
Figure 8

The third and last support you have to worry about is this one next to the power steering pulley. Simply remove the 13mm bolt.

The third and last support you have to worry about is this one next to the power steering pulley.
Figure 9

The third and last support you have to worry about is this one next to the power steering pulley. Simply remove the 13mm bolt.

It makes sense to number these six bolts to keep track of which bolt goes where.
Figure 11

It makes sense to number these six bolts to keep track of which bolt goes where. In addition, these numbers indicate the preferred order of tightening during reinstallation.

Once the alternator bracket is removed, it can be moved out of the way and secured using a zip tire or a wire if necessary.
Figure 12

Once the alternator bracket is removed, it can be moved out of the way and secured using a zip tire or a wire if necessary. It's easy to see the water pump and its housing in this photo (note that the timing bet is also displaced, as I was changing it also during this time).

The water pump should now lift away from the engine block easily.
Figure 13

The water pump should now lift away from the engine block easily. The circular O-ring stayed behind in this case--make sure you remove it and replace it with a new O-ring when you install the new pump.

This less-obstructed photo, with the old o-ring still in place, also shows the two hoses that were detached from the water pump, as well as the two electrical connectors for the alternator.
Figure 14

This less-obstructed photo, with the old o-ring still in place, also shows the two hoses that were detached from the water pump, as well as the two electrical connectors for the alternator.

Here's a close-up of that hammer-head bolt from <a href=# style=color:000080 id='In_text_1' onClick=PopUpMessage('In_text_1','images_small/Pic02.
Figure 15

Here's a close-up of that hammer-head bolt from Figure 1. This bolt is loose in this hole, so it will fall out if you're not careful. You'll need to remove it and place it in the same spot in the new water pump. A caution: you won't be able to do this after you bolt the pump and alternator bracket in place.

New pump on the left, old one on the right.
Figure 16

New pump on the left, old one on the right. In addition the hammer-head bolt, you need to transfer the thermostat housing and its mounting bolts to the new pump.

My new pump housing had a bit of casting flash in this main passage; not wanting to have the coolant flow inhibited at all, I decided to grind this off.
Figure 17

My new pump housing had a bit of casting flash in this main passage; not wanting to have the coolant flow inhibited at all, I decided to grind this off.

I chose a Dremel tool with a cylindrical sandpaper bit.
Figure 18

I chose a Dremel tool with a cylindrical sandpaper bit. The water pump housing is aluminum, and the excess flash was quite thin, so a stone bit would have been overkill.

In just a few seconds, the flash was gone.
Figure 19

In just a few seconds, the flash was gone. There was still a bit of a ridge there, the coolant now would have a much smoother path.

Next, remove the thermostat housing by removing the two 10mm bolts.
Figure 20

Next, remove the thermostat housing by removing the two 10mm bolts.

Another rubber O-ring gasket holds the thermostat in place.
Figure 21

Another rubber O-ring gasket holds the thermostat in place. I used a small screwdriver to peel it back a bit for removal.

With the O-ring removed, the thermostat pops right out.
Figure 22

With the O-ring removed, the thermostat pops right out. Make note of its orientation and install the new thermostat the same way.

The new thermostat goes in the new water pump.
Figure 23

The new thermostat goes in the new water pump. It's a relatively loose fit, even after you lay the new O-ring in place.

The O-ring is pressed into place as the thermostat housing is tightened down.
Figure 24

The O-ring is pressed into place as the thermostat housing is tightened down. Tighten the two bolts to 7 ft-lbs.

The O-ring for the block side of the pump housing sits in a round groove.
Figure 25

The O-ring for the block side of the pump housing sits in a round groove. Make sure you put a brand new O-ring here.

Here's that hammer-head bolt again, and you can clearly see why you need to make sure it's installed through this hole in the water pump before the alternator bracket is secured on top of it and you can no longer access this space.
Figure 26

Here's that hammer-head bolt again, and you can clearly see why you need to make sure it's installed through this hole in the water pump before the alternator bracket is secured on top of it and you can no longer access this space.

One issue I had, which may or may not be an issue for you, was that three bolts on the face of the water pump interfered with the toothed oil pump/intermediate shaft pulley, seen just behind my hand.
Figure 27

One issue I had, which may or may not be an issue for you, was that three bolts on the face of the water pump interfered with the toothed oil pump/intermediate shaft pulley, seen just behind my hand. The solution was to remove these three bolts, take off their spring washers, and reinstall them. Note that the water pump is not in its final position in these photos, but is simply resting underneath the alternator bracket.

Here it's easy to see the three bolts in question.
Figure 28

Here it's easy to see the three bolts in question. Removing the washers lowered the profile of the bolts and allowed the pulley to rotate freely.

Before securing the six bolts that hold down the water pump and alternator bracket, I reattached the two coolant hoses to the back of the pump housing and secured their clamps.
Figure 29

Before securing the six bolts that hold down the water pump and alternator bracket, I reattached the two coolant hoses to the back of the pump housing and secured their clamps.

Start with bolt #1, threading each of the six bolts through the alternator bracket and the water pump.
Figure 30

Start with bolt #1, threading each of the six bolts through the alternator bracket and the water pump. It takes a little effort to align everything, so don't tighten things down until you have all the six bolts threaded.

Tighten the six bolts down to 18 ft-lbs.
Figure 31

Tighten the six bolts down to 18 ft-lbs. Reattach the three support braces. The Allen bolts on the intake manifold support are tightened to 15 ft-lbs. The block-to-alternator support strut should be 30 ft-lbs on the bracket side and 18 ft-lbs on the block side. The bolt on the support that extends to the power steering pump should be tightened to 15 ft-lbs. Finally, reinstall and hook up the alternator.

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Comments and Suggestions:
jc Comments: have a 1999 audi a4 1.8 how do adjust the water pump belt
October 30, 2014
  Followup from the Pelican Staff: That is the timing belt. http://www.pelicanparts.com/techarticles/Audi_Tech/09-ENGINE-Timing_Belt_Replacement/09-ENGINE-Timing_Belt_Replacement.htm - Nick at Pelican Parts  
bill Comments: my 99 jetta is leaking from weep hole can I replace only waterpump face
May 13, 2014
  Followup from the Pelican Staff: Yes. - Nick at Pelican Parts  
TIHO Comments: Hi all,
I just want to say Thank You!
I did the water pump today, the information was very helpful.
May 9, 2014
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
LKA Comments: do you need to remove or touch timing belt if you are just doing the water pump?
April 29, 2014
  Followup from the Pelican Staff: No, not if you remove the entire alternator bracket. - Nick at Pelican Parts  
omar Comments: Audi a4 1.8 turbo water pump re pair cost
March 6, 2014
  Followup from the Pelican Staff: Not 100% sure, it depends on your location. I would call a few local repair shops for estimates. - Nick at Pelican Parts  
paddy Comments: Hi great help with pump housing but is it the same with the a4
1·8 non turbo 97 reg
March 2, 2014
  Followup from the Pelican Staff: This tech article applies to :
Audi A4 (1997-02)
Audi TT (2000-04)
VW Passat (1996-00)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Beetle (1999-02) - Nick at Pelican Parts
 
Ej Comments: How do you change the water pump belt only, do you have to remove the fan or is there a tensioner
May 21, 2013
  Followup from the Pelican Staff: Remove the water pump pulley and the belt will come off. There may be shims underneath the outer pulley so be sure not to lose them since they are needed to set the depth of the belt in the pulley when you reassemble it. - Nick at Pelican Parts  

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