Engine change problem. Water pump impeller chewed up....Where's the pieces? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Byron in Atlanta · 01-01-2011, 01:41 PM

Hello all...I am in the process of installing my new/used engine after throwing the rod in August. I was thinking that I would reuse the water pump from my blown engine as it only had a couple of thousand miles on it. When I removed it, the impeller was chewed completely up. It seems that when the engine blew, metal pieces from the engine case, rods or pistons entered the water channels and destroyed the pump. Any suggestions on how to clean out the cooling system short of removing everything?

JFP in PA · 01-01-2011, 02:11 PM

Actually, I'd go the other way around; your water pump may have came apart (on the track, if memory serves), and the bits blocked some of the water passages to your head and more importantly, the oil cooler area, and that is probably what started the fatal chain of events leading to your rod failure. Not that uncommon, this is why Jake is suggesting changing out the water pump every three years, even if it is working fine...........

Getting all the bits out is a major pain, probably will require total disassembly unless you are very lucky.

Jake Raby · 01-01-2011, 04:55 PM

If one of those pieces, as small as a pencil eraser gets in the right cylinder head capillary, you'll have a cracked head.

You must disassemble the entire cooling system and clean every part.. A flush won't cut it.

If it were mine I'd change the radiators and throw the old ones away.. Gotta take this seriously, if not you'll pay the price the hard way..

Topless · 01-01-2011, 05:09 PM

Quote:

Originally Posted by Byron in Atlanta

Hello all...I am in the process of installing my new/used engine after throwing the rod in August. I was thinking that I would reuse the water pump from my blown engine as it only had a couple of thousand miles on it. When I removed it, the impeller was chewed completely up. It seems that when the engine blew, metal pieces from the engine case, rods or pistons entered the water channels and destroyed the pump. Any suggestions on how to clean out the cooling system short of removing everything?

Yikes! Agreed that your woes are not over. Impeller grenade fragments have lodged themselves in every nook and cranny of your cooling system. Hard to say at this point whether it was chicken or egg (failed rod or failed impeller) that went first. Was your replacement water pump a factory Porsche part or aftermarket?

tnoice · 01-01-2011, 05:49 PM

I may be missing something but I think he did change out his water pump, because he stated that it only has a few thousand miles on it.

Topless · 01-01-2011, 06:05 PM

Quote:

Originally Posted by tnoice

I may be missing something but I think he did change out his water pump, because he stated that it only has a few thousand miles on it.

Yes yes, understood.

Inquiring minds want to know if when the WP was changed, it was replaced with a Porsche factory part or an aftermarket supplier (i.e. less expensive/less reliable) part. My car is at 92k and I will be replacing my wp soon as a preventative measure. Knowing the source of potentially unreliable replacement water pumps is of keen interest to me, and probably other Boxster owners as well.

Jake Raby · 01-01-2011, 06:11 PM

They all fail.. No matter if its OE or not.. No brand is better or worse than another in my experience.

This is why it should be changed on a regular basis.

Byron in Atlanta · 01-01-2011, 06:18 PM

and have the radiators vatted. I will have to further evaluate replacing the radiators as I am out of MONEY! The water pump was 8 months old at the time of the explosion, and was an after market unit from NAPA. The car was not running hot prior to blowing up so I am pretty certain that it was engine parts that destroyed the impeller and not vice versa. Thanks all for the input.

mikefocke · 01-02-2011, 06:57 AM

OEM water pump supplier to Porsche that was much better than the others. One he sold. I thought he said that on a forum a while back. Recent experience now says that isn't right? Or is all he is now saying that they all eventually fail?

Gforrest2 · 01-02-2011, 08:54 AM

Quote:

Originally Posted by mikefocke

OEM water pump supplier to Porsche that was much better than the others. One he sold. I thought he said that on a forum a while back. Recent experience now says that isn't right? Or is all he is now saying that they all eventually fail?

Same recollection here. When I change mine out, I want the most robust replacement.

JFP in PA · 01-02-2011, 09:26 AM

Quote:

Originally Posted by Byron in Atlanta

and have the radiators vatted. I will have to further evaluate replacing the radiators as I am out of MONEY! The water pump was 8 months old at the time of the explosion, and was an after market unit from NAPA. The car was not running hot prior to blowing up so I am pretty certain that it was engine parts that destroyed the impeller and not vice versa. Thanks all for the input.

If your engine had already “detonated”, and was in the process of stopping when shrapnel got to the pump vanes, you wouldn’t be searching for the vanes, they would still be near the pump, along with the chunk(s) of metal shrapnel that tore them loose (which also would not have have had time to been reduced to small bits and dispersed). If the vane debris totally disintegrated and made it all the way to the radiators, they had to have time to do so; the pump failed first.

Mark_T · 01-02-2011, 04:07 PM

quoting Mike "I thought Jake knew of a specific OEM water pump supplier to Porsche that was much better than the others. One he sold. I thought he said that on a forum a while back."

That's what I recall also. For some reason, the peeps at FSI becaome very evasive when asked which brand of pump that is, exactly. Seems to be some kind of a secret.

My car still has the original water pump - 12 years and 116K kilometres later. Because of all the dire warnings, I'm going to change it before I drive the car again in the spring. The fact remains, however, that it has been in there three times longer than recommended and has not detonated.

Hard to know what to think sometimes.

insite · 01-03-2011, 10:14 AM

Quote:

Originally Posted by JFP in PA

If your engine had already “detonated”, and was in the process of stopping when shrapnel got to the pump vanes, you wouldn’t be searching for the vanes, they would still be near the pump, along with the chunk(s) of metal shrapnel that tore them loose (which also would not have have had time to been reduced to small bits and dispersed). If the vane debris totally disintegrated and made it all the way to the radiators, they had to have time to do so; the pump failed first.

i completely disagree. let's say it took ten seconds from the start of the problem until the motor quit turning. at full tilt, byron was likely averaging 6,000 RPM's.

the water pump pulley is a little smaller than the crank pulley. let's say it's 15% smaller. this means the water pump would have turned 1.18 revolutions for each crank revolution.

at ten seconds, we're looking at over SEVEN HUNDRED rotations of the water pump during the failure. this is enough time to circulate the entire contents of the cooling system MANY times over. the missing debris is in the radiators.