Failing water pump

Pulling into the driveway last night I heard a rattling noise from the engine. IMS detector was not red, so good there. Did some reading here last night and figured it might be the coolant pump. When I went out this morning, there was a little puddle under the back of the engine. Mechanic is about 15 miles away. Safe to drive or should I call a flatbed?

If you can confirm it's the water pump (crawl under there and see if you can see it dripping from the bottom of the water pump...it may also look like it's dripping from the coolant hose, but more than likely it's the pump itself). If you can confirm, your leak appears very small at this point. I just replaced mine about a week or so ago myself. I noticed it dripping about like yours at my office, and drove it home (about 15 miles) keeping an eye on the temp needle, no radio to make sure I could hear if something happened, etc.,) and it was fine...fwiw, I never got above about 45 on that trip, as I took all local roads, and kept the RPM's pretty low. Good luck with everything. DS

When my Boxster's water pump started making noise and as best I could tell it wasn't even leaking, I had the car flat bedded 20 miles to a dealer to have the water pump replaced. The cost was IIRC around $100 vs. possibly very serious engine should the pump decide to come apart or the impeller blades shred themselves and the pump stop pumping. If the pump loses its impellers since the coolant isn't being pumped through the engine/radiators it is not flowing past the coolant temp sensor and then usually the first indication you have there's any problem is when someone drives up along side of your car with the horn honking and a frantic waving of arms to get you to look back and see the huge billowing clouds of steam coming from your car. Then the warning light comes on. But, too late. Sincerely, Macster.

agree 1000% with Macster's points above. Comes down to cost of tow vs. cost of new engine? IMHO, I will pay the tow.

Would you rather just replace it yourself and use the tow money towards the parts? These cars are fun to work on and a great experience if you have the time.

Free tow with AAA. Hasn't been to a Porsche specialist in a year, so just as soon have them do it and give the car a once over while they're in there.

the DIY for these water pumps looks a little difficult for the average person. i have noticed a trace of coolant on the outside of my pump, but its not dripping, just gathered on the lower part of the casing. Maybe this is a sign of the water pump on its way out and im trying to decide whether or not to try and replace it myself or have a local shop do it for me.

Don't star the car. a failing water pump can send plastic impeller pieces into the cooling system, which can block the very narrow cooling passages in the head, leading to blockage and cracked heads. Do not fool with this very serious condition.

Valid points, I assume like anything else there are different stages of failure. Although mine had leaked a bit of coolant during the day from when I first noticed it to when I parked it before removing and replacing it, the impeller was totally intact when I pulled it off, but obviously we have all heard stories of impeller fragment totally screwing up an engine. Glad AAA towed it for free, nothing wrong with that. Curious what your indy charges for the replacement, as mine was around $900, and dealer was about $950. @Akshun, I wouldn't say that it is beyond the average person's capabilities, I had the renntech writeup on it, as well as the youtube video of another guy doing it. For me, I couldn't get the coolant hose that connects to the thermostat housing off (others have had similar issues) so I took the T-stat housing off, and needed a new gasket for it which I didn't have readily available, that was the only part of the job that I had to improvise on, everything else was as advertised. Cheers, DS

just do it your self?

If the pump is failing you'll just send more debris into the cooling system from the pump impeller.. Then in a few months you'll end up with a cracked head from a localized hot spot created by the flow of coolant being blocked by said debris. tow it, don't drive it to death.

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When I talked to the techs about water pumps I was told they can leak, a bit. A tiny bit. I was told that a bit of coolant stain/dried residue on the pump casting is ok, but there is a limit on how much is ok. The techs did not share with me the details but indicated how far down or how big the stain was is important. But they both said there should not be any signs of wet coolant. If you are seeing coolant fluid under the pump that can't be coming from some place else the pump is leaking and should be replaced. There is a risk to letting this go. The issue is the pump can suffer a mechanical failure that has the impeller blades contacting the engine casting surfaces which can lead to a non-functioning pump with disastrous consequences. Or the shaft snaps again with very likely disastrous consequences. I have to stress this again that with older cars it is not always an engine blowing up that takes a car off the road for good, but letting a little thing like this water pump go until the engine suffers serious overheating. An older Porsche that needs a new engine from a failed IMSB is just as expensive to fix as one that needs a new engine due to an overheating that ruined the heads, or the block. And because of this expense just as likely to be lost for good. Sincerely, Macster.

Use AAA and get it towed ... tout de suite, mon ami! Mine broke on 25 Oct. It took about 15 secs and it feels just like a broken fan. I happened to be 300m from home. The impeller (seems to be made of carbon fiber rather than plastic but very brittle) broke in mainly 3 big chunks from the shaft and the tips of the impeller rattled against the wall and broke in a few small bits. Managed to catch a few of these bits right at the pump but I'll never be sure if a few more are lying in wait somewhere in the cooling canals. A new pump is in and the car is working great. Hopefully I won't get further issues down the road. You're lucky you had a warning. Put it to good use! Martin

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In case other readers missed the POST #16 above by the OP: he played it safe and got it towed.

Here is a picture of my failed water pump and impeller beside it for general interest. My car had 141k kms (about 87k mi) when it happened. Nice to hear he got it towed! Martin DSCN0458.jpg

Here's a pic of my Boxster's OE water pump after 172K miles. The pump was noisy, not alarmingly so, but enough. I can't say for sure but it does look like the tops of the blades had made contact with the casting surface but even if so when this occurred I can't know. It might have been when it was first installed (at the factory) or it might have occurred as the shaft developed play that I found upon inspection and sealed my decision to have it replaced. Sincerely, Macster.

Thanks for posting! Now I know how the impeller is supposed to fit with the pump shaft. Not sure as well about your mysterious blade tops. They look evenly made that way. Martin

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A higher res pic shows the top edges have been abraded some. 'course with pump in front of me one can see and feel the abrasions. But I never saw a new one so I can't say for sure the tops are really abraded or it is just some kind of poor finishing after the unmolding. Sincerely, Macster.

My new pump comes in on Wed. I'll certainly compare pics and finish. Doing mine pre-emptively, along with the AOS, low temp T-stsat and motor mounts. (left mount appears to have collapsed). Pump, 2 gal coolant, seals, washers, cabin filter, low temp stat w/housing, AOS, motor mounts, new coolant cap (mine has dried residue around it, even though replaced in '07 with new tank), and oil filler tube were $820 shipped.

Perry; If you don't mind, please post a photo of the new Water pump you will be getting so we can compare with Macster's. Would be appreciated! Martin

Mechanic said the vanes were fine--just the bearing was going. First mechanical problem (other than consumables and routine maintenance) in the three-and-a-half years I've owned her.

Good news, then, no worrys! Caught in time! BTW, what year and how many miles on the pump? Mine actually came today, and I'll post a pic when I get a chance, but I can tell you, it looks identical to Macsters, but the slanted part on his that has striations/abrasions is square and smooth, so his had no wear to speak of other than those abrasions. I wonder if just normal usage over that many miles would cause those marks? Not much to it for $260.

Not much too it for $260... well, the OE one in my Boxster lasted 172K miles. I'd rather pay $260 for a water pump every 170K miles (and labor for its replacement) that pay something less for a lesser water pump and the labor for its replacement more often. That labor cost is the biggie. Sincerely, Macster.

Failing bearings in the WP means that impeller contact with the crankcase is imminent.. When the impeller loses support due to a bad bearing the next thing that occurs is impeller failure that leads to the bits being pumped through the system. Thats why its imperative that WP replacement is done proactively, not reactively. The crazy thing is IF the factory would have specified a mileage point for WP replacement everyone would consider it a cardinal sin to drive a single mile beyond that point. Unbelievable.

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2002 69k miles

Well, yeah, but RallyJons only lasted 69k miles, (my 2002 has 49k miles, water pump appears fine, but it is 11 years old now) while the $40 one on my '99 Dodge Dakota (with metal impeller) has lasted 160k miles, so far, so you get my point. I understand machined alloy and a "high tech" composite impeller will always cost more, but for instance, I've installed the Stewart all SS & alloy units in BMWs and only paid $140 for them, and they are an AMAZING water pump. I hope the latest rev of the Porsche ones have better bearings.

The WP on my friend's 2001 Boxster just failed at 50K miles. Very small leak, then it started making noise. All impeller tips are cracked off. He's trying to figure out a way to backflush and get the pieces out of the head. He's got the transmission out... just did the IMS bearing replace (himself) as a preventative action. Any thoughts Jake?

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Until Jake has time to respond my suggestion would be to rig up a way to use a garden hose to back flush the engine cooling system and the radiator cooling system portions of the cooling system. All the coolant hoses will be have to be disconnected. The water pump removed along with the t-stat. Then forcing the water in the opposite direction of flow should have the debris coming out the with fresh water. Likewise with the radiators. Catch the water in a clean large can or bucket or something and observe the amount of debris approximates the missing impeller material.

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Thanks. I will relay the information.

How come I am seeing new water pumps at Parts Geek for half the price you paid for yours? Is there anything against installing these cheaper pumps. Any feed back from posters would be well appreciated along with Pros and Cons for these pumps. Thanks. http://www.partsgeek.com/gbproducts/...FYKK4AodwFAAvg

Hurdi, the Non-OEM pumps have a long history of failing very prematurely...like within months of installation...and they are a bit of a pain in the **** to get to. I just bought an OEM one from Sunset last month for like $240 with the gasket...and as it's genuine Porsche, 2 years warranty on parts, in the unlikely event it fails in the next 2 years.

Here are the pics of the latest Porsche waterpump -56. I swear, comparing it to macsters, mine looks to have the machined face at the impeller, more machined down, so the impeller looks like it may sit deeper in the cavity of the engine when installed. Note in particular the 2 machined fingers that go closest to the impeller. There's no doubt it is a subtley different casting. What thinks you all?

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OEM as in OEM supplier to Porsche? Would it be the Pierburg brand which on Pelican site is shown as OEM supplier but not "genuine Porsche", see link here http://www.pelicanparts.com/catalog/...WATpmp_pg1.htm

No, if you buy from Sunset or Suncoast, you only get genuine Porsche, what we normally call OEM or OE, I forget which is technically correct. Pelican can be genuine Porsche or an OE supplier to Porsche, but not cast or stamped with Porsche part numbers. Their "better", higher priced motor mounts are Rein, which they say is a supplier to Porsche. Who knows, really, though.

I just changed out the waterpump on my '99 996 C2 this weekend. There were no problems with the water pump; the changeout was strictly preventative. I'm fairly certain this was the original water pump. After 13 or 14 years and 65,000 miles, the water pump and impeller look good as new. I'm glad that all impellers don't explode into engine-destroying shards. While the old pump may have been fine, I was glad to find an intact impeller! The job took me all day, but the various DIY's, videos, and tips here were very helpful. I still have a problem with a water pump hose, but I think I'll start a new thread for that problem... Here are the old and new water pumps. The impeller materials look different on the old and new. Not sure what has changed.

Yours looks just like mine. I assume they use a better composite material for the impeller, after this many years and knowing there were impeller failures. Yours also looks more machined than your original. I will be doing mine after the Thanksgiving holiday, along with the AOS and motor mounts. Only 49k on my car, but like you said, everything is 11+ years old. I don't like to wait until something fails then have to maybe pay out the nose to get it fixed in a hurry. I was looking at replacing the hoses too, now I'm not so sure. What kind of shape was the one you took off?

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I decided to replace 3 hoses: The one to the water pump, the large one from the thermostat housing, and the small 90� hose that is on the rear lower right side of the engine next to the engine mount bracket. There are LOTS more hoses in this engine, but these were hoses I was already messing with, or that were easy access. The hoses looked cruddy on the outside, but it seems that this was mostly surface deterioration. The inside of the hoses were fine, and they still seem structurally sound. Removing the large thermostat hose made access to the water pump and thermostat easier, but I would NOT have been able to remove it without cutting it off. Can't do that unless you have a spare. Access to some of the upper spring-hose-clamps was tricky as well. Here was my parts list: Water Pump (996-106-011-56) $233.89 Water Pump Gasket (996-106-340-54) $6.14 Coolant drain plug and washer $2.73 and $0.26 Thermostat 996-106-125-53 $38.97 Thermostat gasket 996-106-326-50 $3.70 Water pump coolant hose 996-106-850-05 $32.03 Thermostat coolant hose 996-106-502-56 $37.55 996-106-233-51 Lower 90� coolant hose 996-106-233-51 $15.35 Coolant Cap (996.106.447.04) $15.96 Shipping $19.97

Dang, and I'm installing the lower temp T-stat, too. I have all those parts, except the hoses. Where did you get yours from. I got mine from Suncoast, and the prices seem about the same, except I got the the whole low temp T-stat, gasket, and housing from Pelican for a lot more, like $70, IIRC. I have to make another order, for a few other things, and I see you're not far from me, that's why I'm asking! Which one is the hose combo that you put in the other post that doesn't fit?

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Got my parts from Sunset Porsche in Oregon. I haven't heard back from them on the ill-fitting hose, but I have another post on the subject, and the consensus is that the rigid coolant line that connects to the hose needs to be replaced. I'll wait and see what Sunset says. If I need another part, I might get it from my local dealer. The hose that doesn't fit is 996-106-850-05. The hose I had to cut to remove is 996-106-502-56. If I had to do it again, I might not replace the 996-106-850-05.

FWIW, for the MKII, many of those parts have changed (with lower prices!!). I gave my vin ('02 C2 with 01/02 build) to Suncoast and the 996-106-502-56 has been updated to 996-106-832-03 for $16, and the 996-106-233-51 has been updated to 996-106-233-55 for $11.