[Cloud9...68]

Well, I'm hoping for the best, but fearing the worst (which is why I can't sleep and am up and this ungodly hour writing this). I may have to eat my words about the wisdom of going with a rebuilt water pump. After initially not getting any leaks, I put a pressure tester on the reservoir to see if there was any air left in the system, and pressurized it to 11 psi. And there it was, that sickening, stomach-wrenching dripping sound - a coolant leak, coming from the water pump area. I'm going to take off the belt cover after work so I can see the whole water pump, pressurize the system again, and pinpoint where the leak is coming from, but I fear it's the impeller seal, or possibly the gasket. If it's either of those, I will obviously be repeating almost the enitre belt change job I just finished. Ugh... At least I'll be REAL good at it by the time I'm done.



So, just a quick question. How much pressure should I put on the pressure tester? I did a search, and found that people have used 18-21 psi. Is this about right? If so, the fact that I'm getting a leak at 11 psi is not a good sign. Oh, well, at least I didn't find out about this leak at the track (I have an event on the 11th, so I need to get this thing diagnosed and fixed by then).



I'll let everybody know what I find. Thanks.

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[unknown4u]

maximum pressure about 1,5 bar.

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[Cloud9...68]

[quote name='rdhayward' post='50355' date='Apr 4 2008, 07:18 AM']Ungodly hour? I was just getting in at that time after replacing the lower balance shaft cover!



I, too, bought a remanufactured water pump and will be installing it today. I took Chuck's (at Paragon) advice on this one, as I initially intended to buy a new pump.



As for your predicament, maybe it's premature to panic. Have you run the car long enough (after installing the pump) to know if it's actually losing coolant? Often the newly installed pump just has to "break in" the carbon seal. Some old-timers would "dry run" water pumps for 15-30 seconds before installing coolant, because the coolant has lubricants that inhibit the break-in.



Just my 0.02 worth. I'll certainly be thinking about this myself by the end of the day![/quote]



I get up for work at 5:30, so starting a potentially depressing thread at 12:30 AM is not my usual routine. I feel surprisingly good now, despite getting maybe four hours of sleep as I was kicking around the sceranios in my head as to how to deal with this thing.



You're giving me some hope. I've never heard of a break-in period on a water pump, but there are a lot of subtleties and nuances regarding cars in general, and this one in particular, that I'm not aware of. Here's my sequence of events:



After finishing up the belt job, I filled the system with coolant, pressurized the system to about 10 psi to get the air out (didn't see any leaks), then started it up, letting it get to temperature (forgot to open the heater, though...), idling for a total of maybe 15 minutes. Shut it down, let it cool off for about 3 hours, the pressurized it again. Saw a few bubbles, but not too many, and still no leak.



The next night, I took it for about an 8-mile spin, hitting a max rpm of only about 4200. Looked under the hood with it running in my garage, and still no sign of a leak.



The following night (last night), I pressurized it again, at 11 psi, saw absolutely no bubbles, and this is when I noticed the leak, which as I said, seems to be coming from the water pump area.



So, what should be my next step? Maybe I should fire it up, let it idle for awhile, and if I don't see any leaks, I'll take it for a gentle spin for about 10 miles, and check it again. If still no leaks, I'll drive it again, harder this time, hitting maybe 5000 rpm to build up some pressure, and check again. If still no leaks, maybe what you're saying is right, and I'll continue driving it moderately for some distance (100 miles?), before really getting on it hard. If course, if it leaks at Step 1, I'll remove the front covers, pressurize it, and pinpoint where the leak is coming from.



Speaking of the pump, I noticed the impeller was quite stiff, and fairly difficult to turn. Is this normal? I also talked to Chuck (and Jason) at Paragon, who told me they have had no problems with their remanufactured pumps. OK, I'm off to experiment. I'll let everyone know how it goes.



By the way, before you install your remanufactured pump, be sure to tap out the two alignment pins from the bolt holes of your original pump, and tap them into the same holes of your new pump. Be very careful, as they're fairly tight, so make sure you support the bottom of your pump very securely before tapping them in. Good luck, and thanks for offering me a glimmer of hope.

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[Cloud9...68]

Update: I started it up, and very soon saw a puddle forming under the car in the same spot, below the water pump <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" /> . Thinking that if the WP seal really needs to set, it would probably help to give it a few revs, so I mopped up the puddle, got in the car, and brought it to a fast idle of about 2000 rpm for a minute or two. Nervously looked under the car and saw... Nothing <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" /> . Let it idle a few more minutes, still no leak, so I took it for a nine mile spin, hitting 5000 rpm several times, and overall driving at a fairly normal, around-town pace. The temperature gauge stayed close to 8:00 oclock the whole time. Pulled it in the driveway, looked under the car, and............ again, dry as Phoenix in June <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" /> . Let it idle a little longer, still nothing, shut it off, waited for the fans to turn off, and everything's still dry.



OK, this is starting to look promising. A break-in period for a water pump - whodda thunk it? Not me, that's for sure. I just hope I didn't damage something by pressurizing it (albeit at a very modest 10-11 psi, about half the maximum rating for the cooling system) before breaking it in. I'm encouraged by the fact that the coolant level in the reservoir is at EXACTLY the same point it was when the leak stopped, so I'm definitely not losing any measurable amount of coolant.



Well, I can say it's a heckuva lot nicer "fixing" this leak by driving the car around, vs. tearing the front of the engine off again. I'll keep driving it, popping my head under the car, driving it, etc., until I'm convinced things are OK. Thanks again, rdhayward. I'll be keeping my fingers crossed for the next several days, for sure.

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[RS Barn]

I was in the Autoparts industry before I started RS Barn. I have toured the largest reman facility in US.

I won't install a reman pump due to labor time to replace on a Porsche.

I check all the pressure caps now and find most leak at 12psi or so. The system is designed to run at 19psi.

I have never had a leak or breakin time on new pumps.

Good luck-Hope the leak stops.

Pete

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[Cloud9...68]

I agree this is very weird. It makes about as much sense as, oh, filling your tires with nitrogen instead of air and expecting them to leak less, but that's another thread <img src="/forum/images/smilies/968/rolleyes.gif" class="smilie" alt="" />



I never actually saw where the leak was coming from; all I know is that it looked like it was coming from the water pump area. I need to replace my power steering belt tomorrow, so I'll try to get up in there and get a better look, but I've now driven the car nearly 50 miles since installing the new pump, and it hasn't dripped another drop. I know leaks, particularly oil leaks, sometimes have a weird way of "healing" themselves, but I can't understan how a coolant leak around the water pump (if that's where it really came from) can do that. I'm open to any and all theories...

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[flash]

i think the cap is rated at 13 psi

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[Cloud9...68]

Well, I found the source of my leak, and thankfully it's not the water pump impeller bearing or gasket. It's strictly coming from the black plastic doohickey that connects with two allen head bolts to the front (facing the radiator) of the water pump. This piece connects a single small diameter hose, which runs across the front of the engine, between the engine and the radiator. The other end of the hose goes into the bottom of the reservoir. I took a picture of the doohickey, but wasn't able to upload it because the file size is too large <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" />



Anyway, the leak is coming from where this piece mates to the water pump. At this mating surface, within a groove inside the doohickey, sits a flat o-ring. I think that if I replace this o-ring, my leak will go away. The surface of the o-ring that mates to the water pump does look pretty rough and pitted.



Has anybody had to replace this peice before? I couldn't find it in either the workshop manual, or in my parts list. If anybody has a part number, that would really help. Do you think this is strictly a dealer item, or is there another source for it? Pete, any ideas or experience with this piece?



I have a track event next Saturday (4/12) that I would dearly like to go to. If for some reason I'm not able to locate this particular o-ring in time for the event, does anybody have any tricks I could use as a temporary fix? I suppose I could try turning the o-ring over, as the non-mating side looks much cleaner than the mating side. What about some sort of sealant? Thanks in advance.

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[xrad]

If you want it immediately, local autoparts/hardware store generally carry O rings. If not, home depot or the like often caryy large assortment of o rings.



If you want viton O's:



http://www.smallparts.com/products/descrip...CFQNEPAodHgNIMw



Try Pelican?



From and earlier post in this thread, H20 pump should not be hard to turn. Snug, but not hard.

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[Cloud9...68]

Congratulations! That makes two remanufactured pumps within a week of each other with no issues (at least so far!). Keep us posted if you run into any problems with it. By the way, did you tap in the two guide pins as I had suggested?



[quote name='xrad' post='50468' date='Apr 6 2008, 07:59 AM']If you want it immediately, local autoparts/hardware store generally carry O rings. If not, home depot or the like often caryy large assortment of o rings.



If you want viton O's:



http://www.smallparts.com/products/descrip...CFQNEPAodHgNIMw



Try Pelican?



From and earlier post in this thread, H20 pump should not be hard to turn. Snug, but not hard.[/quote]

Well... Given that this o-ring has a very specific shape (being flat, as opposed to round), I'd be a little nervous about putting in a standard round-walled o-ring available at a hardware or autoparts store. Hopefully either the local dealer (at a 1000% markup, I'm sure <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" /> ) or Paragon or Pelican can come up with one. I'll also call Pete at RS Barn.



I would say the pump's impeller was snug, as opposed to gunuinely hard, to turn. It's not leaking, anyway, so things seem to be OK with the pump itself.

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[Cloud9...68]

My brother has some magic, file-shrinking software, which he used to shrink the picture of the fitting the o-ring of which is leaking, so here's a picture of what I'm talking about:



As you can (hopefully) see, the surface of the o-ring is pretty rough and pitted. Hopefully, you can also make out the fact that the walls of the o-ring as very flat, as opposed to round like a standard o-ring. This is why I'd prefer to go with either the exact part from Porsche, or one whose dimensions match EXACTLY with the original.



If I can't find one in time for my track event next Saturday, what do you guys think about turning the existing o-ring (more like "square-ring") over, and applying some Permatex designed for cooling system parts? Thanks.

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