Opinion: 10year old OEM waterpump, 40k miles: reuse or replace? (tbelt job)

MarkRobinson · 02-08-2010, 01:24 PM

Just curious.

Also, Pelican has rebuilt units: heard from one source (ex-951 engine builder) that rebuilts fail more often than not, but I only have positive personal experience with 928 waterpumps. Comments?

Leave the OEM (new 10 years 40k miles ago) in place?

Replace with rebuilt from Pelican?

Replace with new OEM from Pelican?

Mark

racer · 02-08-2010, 01:33 PM

I would replace it from an age concern.

carlege · 02-08-2010, 01:57 PM

Quote:

Originally Posted by MarkRobinson

Just curious.

Also, Pelican has rebuilt units: heard from one source (ex-951 engine builder) that rebuilts fail more often than not, but I only have positive personal experience with 928 waterpumps. Comments?

Leave the OEM (new 10 years 40k miles ago) in place?

Replace with rebuilt from Pelican?

Replace with new OEM from Pelican?

Mark

Really? do you think they are making "NEW" pumps?

MarkRobinson · 02-08-2010, 01:59 PM

Yes, more than one source lists New pumps: $300-range. Appears to be common.

Mark.

oldass31 · 02-08-2010, 02:30 PM

Personally, if the car isn't overheating, there is no play/noise with the waterpump pulley, and the car doesn't have/won't have any performance bits put on, then I would leave the waterpump alone. Otherwise, I would buy a <i>new</i> waterpump. The only rebuilt parts I ever buy are parts that are easy to replace. Like alternators and throttle bodies.

MarkRobinson · 02-08-2010, 02:32 PM

Generally I agree, though I heard there was a "clutch master/slave cylinder" relationship here where if one's replaced (aka: t-belt), then the WP is soon to follow as the new tension takes it's toll. Course, my car is a turbo S with the mechanical tensioner. Hmmm

oldass31 · 02-08-2010, 02:53 PM

Quote:

Originally Posted by MarkRobinson

Generally I agree, though I heard there was a "clutch master/slave cylinder" relationship here where if one's replaced (aka: t-belt), then the WP is soon to follow as the new tension takes it's toll. Course, my car is a turbo S with the mechanical tensioner. Hmmm

This has struck a chord with me because two months ago I replaced the T-belts. (The PO could not tell me the last time they were replaced) Before I replaced the belts however, the temperature in my car was fine, but now, the car seems to be overheating (100+ C) in 5 C weather. I'm still in the process of venting the coolant and checking fan speeds so a relationship with the waterpump is one I didn't think of...crud.

white944cup · white944cup's Garage

I've always heard that new pumps are good for 90K miles. The original one in my 88 Turbo is now 21 years old with 68K miles on it and it seems to be fine. I checked it for leaks, shaft play etc. when I replaced the timing belt at 45K and when I recently re-tensioned at 60K and the pump seems to be holding up well. Personally, I would not take a chance with a rebuilt pump.....I have heard about quite a few failures, and the potential for disaster if the T-belt gets trashed far outweighs the cost savings of a rebuilt pump. Install a new one and sleep well at night.

Yellowb1rd · 05:26 PM

replace them both at the same time. The waterpump is driven by the timing belt, is it not? It's a prudent decision, because this is an interference design, and if the waterpump fails/seizes and the timing belt snaps, you're starting all over again, except with damage to the head to address on top of it. You replace them both at the same time, and it takes the ??? out of the equation.

oldass31 · 09:39 AM

Quote:

Originally Posted by Yellowb1rd

replace them both at the same time. The waterpump is driven by the timing belt, is it not? It's a prudent decision, because this is an interference design, and if the waterpump fails/seizes and the timing belt snaps, you're starting all over again, except with damage to the head to address on top of it. You replace them both at the same time, and it takes the ??? out of the equation.

Are you suggesting that if the waterpump seizes first, then the static waterpump pulley could cause the timing belt to break? I imagine in such a scenario one would see the coolant temp skyrocket and could pull over before the belt breaks. The pulley is not a sprocket design. If it was, then I would easily understand how a seized pulley would cause the timing belt to immediately break, but it's not. Also, the waterpump pulley is not on the driven side of the belt but on the return side so it should have a little extra slack.

I feel that if you properly tension the new timing belt on the low side of factory range, then the load on the waterpump pulley shaft isn't enough to cause any likely problems.

However, if I found myself in a scenario where the coolant suddenly skyrocketed, I would pull over but I would NOT wait for the car to cool and attempt a restart. A seized pulley could cause the timing belt to loosen the belt tension and cause the belt to jump teeth upon restart with the starter motor.

I think that a waterpump is a lot more likely to fail than seize and the only way a waterpump could break our timing belt is if coolant were to leak onto the belt for a period of time. I say check for coolant leaks at the 3000 mile belt retension to put your mind at ease.

jkb58 · 02-09-2010, 10:40 AM

Generally, the common failure with the 944 water pump is the seal failure. It will start leaking coolant down the face of the block. Seal failures may have some dependance on age.

Bearing failures that end with the shaft/pulley seizing are going to be much more likely due to mileage, not age. If the shaft seizes, it will overheat and tear up the timing belt in very short order.

Yellowb1rd · 11:19 AM

Nothing good can come out of trying to cheap out by putting off the replacing of the waterpump. As the last post mentions, a seized shaft will tear up the timing belt in short order, and I don't think I'd want to deal with worrying about being stranded because I needed to shut off my motor - waiting for WARNING in the form of leaking fluid and high temperatures. Why take the chance? Since the timing belt is off, it's pretty easy to replace the waterpump anyway. The only issue is cost, but it's probably a good idea to pay on the front end as opposed to paying more in time and money on the back end. Consider it insurance, and insurance pays off when you need it. Also, insurance gives you piece of mind. You're paying a little extra time and money to not have to worry about being stranded, and damaging your expensive piece of machinery. This is what owning a Porsche is all about. We all had to be willing to make these decisions when we bought ownership into these fine vehicles. If you can't realize that, then it's time to buy a Ford or Toyota. It's just a no brainer.

oldass31 · 02-10-2010, 07:45 AM

Alright, y'all have convinced me. I need to replace my waterpump. So I replaced my timing belts about 120 miles ago and didn't replace the waterpump then because there were no leaks, noises, or shaft play.

PelicanParts says it is REQUIRED that I replace the timing belts if I replace the waterpump, but should I really re-replace timing belt parts that are 2 months and 120 miles old? To comply seems really extreme and paranoid.

carlege · 02-10-2010, 09:34 AM

Quote:

Originally Posted by oldass31

Alright, y'all have convinced me. I need to replace my waterpump. So I replaced my timing belts about 120 miles ago and didn't replace the waterpump then because there were no leaks, noises, or shaft play.

PelicanParts says it is REQUIRED that I replace the timing belts if I replace the waterpump, but should I really re-replace timing belt parts that are 2 months and 120 miles old? To comply seems really extreme and paranoid.

No dont replace the timing belt your reading too much into it

smokin_944 · smokin_944's Garage

I have been driving Porsches a long time and I have never thought that you replace the WP every time you change belts. For those with shop manuals, do a search or visit Clarkes. I change the pump at every second belt change. IF the pump leaked or was showing signs I would change it. Otherwise... Every 60k is plenty.

Yellowb1rd · 09:14 AM

Most of here have also been driving Porsches for a long time, myself included. Most of us have probably seen our share of stuff that breaks when it 'shouldn't have' too.

Replacing the water pump EVERY 30K may be overkill, but he's just changed his timing belt, and his existing water pump has ~40K miles on it. The next time he changes the timing belt, his water pump will be at the ~70K(assuming every 30K) mile mark, and that's just rolling the dice. If he changes it now, then he should be ok for another 60k miles (or two timing belt replacements from now) - so long as he periodically checks the water pump for excessive noise, and leakage of any kind, as smoking_944 alluded to. Also, this waterpump is 10 years old, and mileage isn't the only thing that affects parts like these. Time can too. If he replaces the waterpump now, he'll be back in sync with his belt. Preventive maintanence is never a bad thing, especially on a PORSCHE that is 20+ years old

TexasBlake · TexasBlake's Garage

IMO, 10 years on ANY water pump is a long time. I am not surprised when water pumps fail on any car that's 10+ years old.

rluciano · 02-13-2010, 10:21 AM

I agree 30k miles or 2.5 years on timing belt and double that on water pump. I went 60k on first timing belt. But with Texas heat, not again.

89-944NA · 89-944NA's Garage

Change the pump every SECOND belt change. Before you remove the cam and balance shaft belt, mark an arrow on the belt to denote the direction of rotation of the belt.

nize · nize's Garage

rebuilt pumps can work like new, or fail very quickly. are you a gambling man? do you feel lucky?

personally, i would replace the pump with a brand new unit since it sounds overdue.