Boxster Can't Hand-Turn New Water Pump Installed

[JNC]

My 1999 Boxster (90K miles) started leaking massive amounts of engine coolant. I removed the old water pump - WP (had plastic impellers and was original since metal gasket had to be cut) which had a failed shaft bearing determined by excessive shaft play once removed.

I ordered an Ebay replacement water pump (Parts Master - China) that came with metal impellers. The replacement water pump fit up very well to the bolt holes and block and seemed identical to the old pump (except difference of impellers stated above). However after installing the new WP twice without the belt installed, the new metal impellers were striking the engine block, thus not allowing hand-turning of the WP, from one impeller to the next. I inspected the old plastic WP impellers and noticed that they had some wear mainly across the top of the impellers, but also some on the ends, although none were broken or mangled, only smooth wear. I also noticed some some smooth black plastic marks across approximately one/half of the round opening on the engine block where the old plastic impellers apparently wore some onto the block over time or maybe from WP bearing failure.

After the new WP was removed after twice installing, I noticed scuff marks on the ends of several of the metal impellers from my attempting to hand-turn the installed new WP. I also noticed scuff marks on the engine block from the attempted hand-turns where the 2 flow seal 'posts' are located on the block.

Question: Do you think that a slight filing the ends of the new metal impellers, until I can hand turn the water pump installed, without any restrictions, will correct this problem? I don't want to deposit metal filings into the coolant system, causing engine failure as I have read about here.

Also, given the time I've spent resolving this, I've forgot where the 2 long WP bolts (out of the 7 total) go back...I think they go into the holes where the WP bolt holes has ferule extending out of 2 of the WP holes?

[Steve Tinker]

You are gambling big time using "unknown" Chinese suppliers - I bet they'll run a mile when their pump grinds through your block....

DONT use metal impeller water pumps - even if they fit initially, any slight wear on the shaft will cause the impeller blades to wobble & grind away your aluminium block = new engine !!

You are messing with one the cars major systems - why would you go cheap when the downside is total failure and huge $$$. A genuine Porsche pump costs peanuts in comparison.

I won't even comment on the filing of the impeller blades to make it fit.....

[jcb986]

Call Sun Coast In Florida...they have good prices on parts. I would go with the original equipment here.

[ketsa]

Originally Posted by JNC

Also, given the time I've spent resolving this, I've forgot where the 2 long WP bolts (out of the 7 total) go back...I think they go into the holes where the WP bolt holes has ferule extending out of 2 of the WP holes?

That's right, the longer bolts belongs to the shuffle pinned holes.

[JFP in PA]

You just discovered why you should not buy stuff like water pumps based upon price alone; you typically get what you paid for…… Rather than fuss with the knock off pump, I would either return it, or throw it in the trash. We have never had any luck with aftermarket water pumps on these cars, and the ones with metal impellers can chew the Hell out of your engine case when they fail, filling the cooling system with metal filings. Not a good thing on an engine with a lot of very small water passages……….. Get an OEM pump.

[MileHighBoxster]

double oops.

[MileHighBoxster]

That's why I let my dealer handle important repairs. Finding the best price on parts that are correct, is prudent. Trying to find the cheapest parts, is not and may cost more in the long run.

[pothole]

My guess is that the pump they sent is for the 987/997 series / M97 engine.

I replaced the pump on my 986 last year with an official Porsche part and had exactly the same problem. The pump bolted up to the block perfectly but the impeller caught the block.

Turned out I had been supplied the wrong part. I had noticed the part number on the box started "997" when most parts for 986's start "996", but assumed that some parts were cross compatible and in those cases they'd ceased supplying the earlier part.

But no, it was the wrong part.

What was really scary in my case was that I actually fitted the pump and belt and had turned the engine over for 30 secs to circulate the fresh oil I had popped in. The only reason I found out about the wrong pump was because I had a tiny weep around the gasket and I removed it to see if there was dirt or some other issue. Took the pump off to find the ends of the impellers slightly shaved! Thank god the impeller was plastic.

Anyway, bottom line is that the pump from the 987/997 series will bolt up nicely, but the impeller is a tiny bit bigger.

[JNC]

Thanks to you all for providing me with such important info. I'm reordering a new OEM water pump today with the plastic impeller. Thanks again!

[JNC]

Installed Porsche OEM water pump today with ceramic impeller...fit great and turns well without any obstructions. Had bought an Autozone replacement drive belt (Dayco) which also didn't fit (too short), so from aftermarket water pump & belt drive aftermarket parts problems, decided to order a new belt from SunCoast....fit perfectly and works great. I've learned from this all the risks of using aftermarket Boxster products!
Thanks all!! This is a great website for technical support!