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Diagnosing And Replacing A Faulty Water Pump On A 2003 Volkswagen Jetta

The water pump impeller is plastic on many Volkswagens. It gets brittle and can break into pieces or spin freely on the shaft and not push any coolant. We checked the sensor, felt the radiator and had a strong suspicion that was the case on this 2003 Volkswagen Jetta, but how do you tell without removing the pump? Since the car had overheated, we were going to replace the thermostat, and with the thermostat removed you can reach in and feel the water pump impeller and verify if it’s broken or loose. This article will show you how to remove the thermostat, check the water pump and replace the pump, if necessary.

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We bought another loaner. It’s a 2003 Volkswagen Jetta that’s loaded with heated leather seats, heated power mirrors and the 1.8L turbo engine. It’s got the premium stereo and it’s my favorite color, black. It only has 125,000 miles on it and it’s current on its timing belt and other services. I thought we were going to have to do a minimum of service to get it ready to use as a loaner, until I noticed the temp gauge reaching for the red.

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We all know why we recommend doing the water pump and all the rollers when we sell timing belt services. We even have a nice display to show our customers how it all works, and 90 percent of the time our customers will take our advice and do the complete service. Occasionally, someone will say, “Don’t do the water pump; I’m going to sell the car.” Guess what I bought?

The water pump impeller is plastic on many Volkswagens. It gets brittle and can break into pieces or spin freely on the shaft and not push any coolant. We checked the sensor, felt the radiator and had a strong suspicion that was the case with our new loaner, but how do you tell without removing the pump? Since the car had overheated, we were going to replace the thermostat, and with the thermostat removed you can reach in and feel the water pump impeller and verify if it’s broken or loose. This article will show you how to remove the stat, check the water pump and replace the pump, if necessary.

As with all repairs involving cam and crank timing or alternator removal, we will disconnect the battery. To reach the thermostat, you do need to remove the alternator, so let’s get started.

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DIGGIN’ IN

 

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1. Remove the two engine shields. Quick screws hold in the top shield and front shield (see Photos 1 and 2).

 

Photo 3

2. Disconnect the intake duct at the throttle body (see Photo 3), remove the four torx bolts and then remove the throttle body. We had to key the car on after we pulled the throttle to roll up the windows. That makes it necessary to run adaptation on the throttle after we are done, so roll the windows up before you disconnect the battery.

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Photo 4

3. To remove the alternator, we had to first remove the serp belt (see Photo 4) and belt tensioner, so remove the serpentine belt and the three bolts that hold the tensioner on.

 

Photo 5

4. Remove the two bolts that hold the alternator on and then remove the alternator, or just move it forward out of the way. We could now see the thermostat cover (see Photo 5).

 

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5. Once you remove the thermostat cover, you can pull the thermostat (see Photo 6) and check the pump impeller. Reach into the block and toward the front of the engine to feel the impeller. It’s usually very apparent if the impeller is loose or broken.

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6. So, it turns out that we do have a broken impeller and have found the source of our overheating, so now we have to remove the timing belt and replace the water pump. We will also install our

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new thermostat, but we won’t reinstall the alternator or throttle body until after we use our airlift and verify the thermostat O-ring is seated and won’t leak. Now let’s start on the water

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pump.

7. Unplug the coolant level sensor, and then remove the two screws and the two hoses to get the reservoir out of the way (see Photo 7). One hose is underneath the reservoir, so be careful when flipping it over (see Photo 8). The plastic can be brittle and crack if you’re too rough.

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Photo 9

8. The power steering reservoir needs to be removed next. We removed the one nut holding it in (see Photo 9), clamped off the hoses and removed the front hose. We laid it near the firewall to get it out of the way. Feel free to completely remove it, if you desire.

 

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9. Before removing the right upper motor mount, raise the car and access the crank pulley

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and lower timing cover. Remove the RF wheel (see Photo 10), then the intercooler duct

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(see Photo 11), and then remove what VW calls the belt cover. The intercooler duct is held in

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by only one nut (see Photo 12) and two clamps (see Photos 13 and 14).

 

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10. The right-side motor mount needs to be removed next. Volks-wagen recommends using a cross bar to support the engine from the top, but that can really get in the way. So, we use a good jack with a large rubber pad (see Photo 15) to support the engine before we remove the

Photo 16

mount. Be sure the lift is sitting on the safety before putting the jack under the car. Remove

Photo 17

the two bolts (see Photo 16) that hold the side bracket to the mount and the three bolts that hold the mount in (see Photo 17).

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Photo 18

11. Remove the two clips (see Photo 18) that hold the upper timing cover on, and then remove the bracket to which the engine mount was attached. There are three bolts (see

Photo 19

Photo 19) that hold it on and you may have to raise the engine slightly to get it out of the way.

 

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12. There aren’t really any ­special procedures to do a ­timing belt on this model, so just line up

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the timing marks. We put a dab of Wite-Out on the marks so it’s easier to see them (see Photo 20). We then remove the four Allen bolts (see Photo 21) that hold the crank pulley

Photo 22

on, and the four bolts that hold the lower timing cover on (see Photos 22 and 23). We can

Photo 23

Photo 24

now see the timing belt, tensioner and roller and the water pump (see Photo 24).

13. Normally, we are ­installing all new parts so we can unbolt the tensioner and just take the belt

Photo 25

off. A new tensioner comes collapsed, so once the new parts are installed and we make sure the timing marks are aligned, we just pull the pin (see Photo 25) on the tensioner and we’re good to go. It’s important to check the engine code to make sure you get the correct parts ­because VW and Audi made ­several variations of the 1.8L and 2.0L motors.

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14. We will reuse all of our parts (except the water pump) ­because they were installed 20,000

Photo 26

miles ago, so we need to collapse the tensioner (see Photo 26) to ­remove and reinstall the belt. The factory tool part number is T10092. It’s basically a 5mm x 0.8 bolt that is 60 mm long and a large washer. Either works well. Slowly screw the bolt in until the belt slides off the water pump.

 

Photo 27

15. Remove the three bolts that hold the water pump in and remove it. We can see the impeller came out in pieces (see Photo 27). Clean up all the mating surfaces and install the

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new pump (see Photos 28 and 29). Hook up your airlift and make sure the thermostat and water pump won’t leak (see Photo 30). If everything checks out OK, refill the cooling

Photo 30

system and double check for leaks. We don’t want a comeback because of a pinched or cut O-ring.

16. Everything looks leak-free, so we reinstalled our timing belt and checked our marks (see

Photo 31

Photo 31). Unscrew the tensioner to tension the belt, and then rotate the engine over two times and recheck the marks. If everything lines up, reinstall the lower timing cover and crank

Photo 32

pulley (see Photo 32). Install the belt cover and intercooler tube and make sure the rubber couplers and clamps are secure. Even a small leak can give you driveability problems and a check engine light. Torque the wheel and let’s finish putting it all back together.

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17. Reinstall the upper engine mounting bracket and the upper timing belt cover. Install the engine mount and bracket and hook up the power steering reservoir and coolant reservoir.

18. Reinstall the alternator and serpentine belt tensioner and belt.

 

Photo 33

19. Put the throttle body back on and hook up the air duct. We put the engine covers back on and we are ready to start it up (see Photo 33). The car runs great and I’m ready to send it out as a loaner.

We’ve done hundreds of these water pumps over the years and there are many variations of ­timing belt setups, depending on manufacture date, engine code and where the car was made. That’s why it’s so important to get the engine code when looking up the parts. The code is usually stamped on the cylinder head and is also on the engine sticker on the timing cover. You can also get it by running the VIN number.

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What’s most important is to educate your customer about the importance of doing the complete job. They may remember the low price they paid, but will quickly forget your recommendation to replace the water pump, or your warning that they will have to pay the labor again should the water pump fail. Worse yet, the tensioner or a roller could fail and cause a catastrophic engine failure a year after the timing belt was done, and you know who would get the blame for that.

So, get a timing belt display from one of your suppliers and save some worn out or broken parts to show your customers. It’s easy to sell the complete job with a little show and tell. 

 

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