This forum is a little light of DIYs so I thought I’d document the water pump R&R my buddy and I did today on my ’05 Cayenne S. The old pump was rattling at ~80K miles, and I figured it better to replace before it totally let go.

I dropped the car at his house while I went to pick up the pump and meet a guy for a lunch meeting. When I got back to his place an hour-and-a-half later he had already removed the front splash guard, drained about a gallon-and-a-half of coolant into a bucket, and removed the water pump. Pretty nice.

All work can be done on level ground. Best idea is to start with a cool engine, for obvious reasons. Tools/supplies needed include torx sockets and bits, a 24mm open-end wrench, ratchet and 3” extension, medium phillips and standard screwdrivers, large wrench (22 to 24mm or adjustable wrench) for the belt tensioner, water pump and gasket, distilled water and/or proper coolant, two gallon bucket or similar receptacle for drained coolant. You may need an OBD tool if you try to restart while throttle body is unplugged. Grab some old towels. Step-by-step was something like this:

Remove forward splash guard: Screws in with a combination of Torx and Phillips screws.

Locate drain plug under right (passenger) side of radiator. It’s blue and faces downward. To loosen, use the side of the standard screwdriver slid between the front skid-plate and break the seal. Open the cap on the radiator reservoir tank, place your bucket under the drain plug. You should be able to back it out with fingers from there. Drain about two gallons into the bucket and replace drain plug.

Under the hood, remove the shroud that says “4.5 liter” by lifting straight up. Remove t-shaped pipe that routes air into the throttle body by loosening the four hose clamps, taking out the collapsible sections, and using a torx bit (not sure of size) turn the plastic screws on top of the T-pipe a couple of turns. They are not threaded, so take a flat head screw driver and lift up on the screw from the bottom as you turn the head back and forth. Then grab the head of the screw with pliers to remove them. Note that there is a vacuum line that goes up into the bottom of the T-pipe. Squeeze the plastic release on the vacuum line to remove it.

You’ll need to get the dipstick tube out of the way. There’s one screw that’s obvious. The radiator hose on the left side is in the way too. Loosen the hose clamp and work the hose off the end. There is a smaller hose with clamp that’s in the way too, in addition to an electrical connection to the throttle body. Disconnect both.

The water pump is behind the top pulley on the serpentine belt. The pulley attaches with three torx screws. Go ahead and loosen those screws, with the belt still tight, but don’t remove.

Locate the serpentine belt tensioner. It is big and hex-sided. Using the 24mm open end wrench, lever back the tensioner with one hand and flip the serpentine belt off the top of the pulley. Now go ahead and remove the three torx screws from the pulley and remove. Once the screws are removed, wiggle the pulley back and forth to get it off the water pump.

You now should have pretty good access to the water pump. It is attached with eight torx screws. There are several other screws you may end up taking out unnecessarily, but no worries. Just put them back in once the pump is out and you figured out you didn’t need to remove them.

When you pull the pump, there will be about a quart of coolant behind it. (You should try to catch as much as you can in a big pan or an old trash towel, since it’s poisonous and dogs tend to lap it up.)

Actually, this is when I arrived. By the way, note that the gasket is a compression type, not very flexible, and will deform if bent. We found it easiest to place the gasket in place and then slide the pump in place. It takes a little negotiating, and note that there is a wiring harness at the top with a metal bracket that goes on the outside of the pump, with two screws that double-duty as water pump and wiring harness bracket screws. If you put the bracket under the pump, it won’t seal. At all.

Screw all eight screws back in place finger tight and torque down in a star pattern, as best as you can. I don’t know the torque specs, but Ryan said the screws he removed weren’t extraordinarily tight at all. Remember the gasket will flatten too much if you crank too tight.

Now you can replace the pulley. Once it’s tight, get the belt back in place. It was helpful to have two people here, so that one could pull on the tensioner and place the top of the serp belt on the pulleys, while the other gets underneath and aligns the belt on the bottom pulleys. After the belt is back on the pulley, tighten the 3 pulley bolts a little more.

Replace the big hose (on the left side) you took off to get out of the way.

Here is the kicker. If you don’t do this, you’ll probably be fighting with air in the cooling lines. Remove the other big radiator hose (right side) that goes into the top of the radiator and fill with your coolant mixture. Do this by sticking a funnel in the hose and pour about 1 gal of coolant in the hose. I had just had my coolant completely flushed and replaced when the rubber hoses under the manifold ruptured (about 6 months ago under CPO warranty), so we reused the coolant captured in the bucket. You can tell when the rad is full; the water will fill up into the hose. Replace the hose and reposition hose clamp.

Reassembly from here is the reverse of the removal. I just used the distilled water to replace the coolant lost, since it was pretty fresh and it doesn’t get that cold here in Dallas. If you turn the key on during the job while throttle body is unplugged, the check engine light will come on. Use OBD tool to reset it.

All told, for the two of us, we probably spent five man hours. If we had these instructions before we started, it would have taken about 3 to 4 hours. It was definitely an advantage to have two people, but it’s not what I’d call a difficult job. The dealer here in Dallas wanted $838 for the job, plus all the whatevers. A good indy shop wanted just under $700. My buddy also found me a new Laso pump and gasket for $168 total.

After driving around for about an hour, I let it cool and checked the level. Only had to add another eight ounces or so of water, so I think the fill from the radiator hose trick paid off. Hope this helps. Sorry I didn’t take pictures, but it’s pretty clear once you’re in there. Good luck.

Ryan/Dave

 

Great write up!! Pics would have been nice though. Looks like you saved a bunch of money. I just had mine replaced under warranty because it was rattling like yours but at 30,000 miles. The engine is sooooo quite now.

 

Thanks for the great write up. I thought I'll post a couple of pics. Only thing I did different was not removing the right and left large coolant hoses. First time replacing the water pump since brand new, now have 150K miles! Yes coolant pipes been changed twice to aluminum ones and the T connector been changed, all by Walter's Porsche.

 

I did not remove the big hoses, therefore did not fill the coolant through the radiator hoses. Well, now I can't fill the system with coolant. Any suggestion or do I have to backtrack and fill thru the upper radiator hose?

 

Don't know, but I hear it's a PITA to burp a Porsche. Would be good if you post the resolution here. If you took it in for a coolant flush, it would resolve your problem: I bet a dealer wants $200. I wouldn't let JiffyLube or some drive-in quickie touch it. I'd try going back in through the hose and see how much you can get back in the radiator. At least you don't have to take the pump off. You should be able to take off the plastic shrouds and right side of the air hose to throttle body to access the rad hose. Fill into the hose, not the radiator. Do all this with a cold engine, then drive it and check level at fill tank. Good luck.

 

Thanks for the response, I'll have to do just that! Should have listen to you, but did not have the Porsche coolant at the time!

 

Well I just finished finally. Took me about 8 1/2 hours with no break. Wasn't easy by any means but seems to be working fine so far as it doesn't seem to be leaking. (Knock on wood) The hardest part was getting the hoses off. Also,the screw holding the oil dipstick was stripped so I had to work around it which definitely made it more challenging. Even with adding coolant to the hose before attaching I still had to add more after running for a bit. I've never attempted anything mechanical on my vehicles so I'm pretty happy with the outcome. Yesterday I went to the dealership and picked up the pump with the gasket. The parts dept looked up my VIN prior on order to give me the correct part but somehow I was still given the wrong gasket. The gasket that I removed was metal and flat and the one they gave me was rubber and had grooves. Luckily, I was able to reuse the gasket that was on there or else I don't know what I would of done given the holiday weekend. I'm going to stop by the dealership Tuesday to return the other one just to make a point.

 

Just did this job over the weekend. I had a knocking noise coming from the vicinity of the water pump; it was audible at idle when standing near the hood. Took me about 6 hours, it wasn't hard, but there are some frustrating parts due to the tightness of the space between the radiator fans and the drive belt pulleys.

I also replaced the drive belt while I was there (7 years old/83K miles). Replacing it added about 2 hours to the job and was easily the most frustrating part of the job. There are a bunch of quick release PCV lines and vacuum lines that needed to be disconnected, and doing that without breaking things is challenging. Especially when you're dealing with 7 year old PCV fittings that have become a bit brittle.

Pump:$175, gasket: $4, and Drive belt: $110. All sourced locally from an import parts place. I could've saved a little more by ordering online. Cheaper than the dealer though.

 

What water pump brand did you guys use?