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A common failure

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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?




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 OEM 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.

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
... I'd remove all of the hoses, tubes and even the radiators to make sure they're clean of residue.
Don't even think of reusing your oil cooler on the new engine (it'll be full of metallic pieces).
Happy Boxstering,
Pedro

Pedro Bonilla 1998 Boxster 986 - 284,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna
as the car was running well and not overheating when the engine failed. Even if an impeller on a water pump disintegrated, I expect that the overheating would be much quicker than the time needed to spin a bearing or throw a rod. I tend to think it was oil starvation that caused the problem. I definitely plan to throughly clean the cooling system and have the radiators vatted.
... an Accusump System.
I'm installing mine next week.
That should take care of the oil starvation.
Happy Boxstering,
Pedro

Pedro Bonilla 1998 Boxster 986 - 284,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna
My Accusump is sitting in a box in the garage. Do you know where I can get some pictures of a Boxster installation? LN has a couple of pics, but nothing showing the hole through the firewall. I would love to exchange some photos etc on doing the upgrade.
... where you're going to tap into the oil where you drill through the firewall.
I don't like tapping next to the filter using a spin-on adapter because you have to use a shorty oil filter which I don't like.
Also I don't like routing the oil line to the bottom of the engine.
I'm working on offering a simpler way of doing it which will also use a shorter oil line, but I'm a few weeks from having the prototype ready.
I'll post here once it's ready.
Happy Boxstering,
Pedro

Pedro Bonilla 1998 Boxster 986 - 284,000+ miles: http://www.PedrosGarage.com
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

Racecar spelled backwards is Racecar
"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"
"If you wait, all that happens is that you get older"... Mario Andretti
"Being second is to be the first of the ones who lose" ... Ayrton Senna
Just going to buy a gross of shorty filters! I will share here too my experience. FYI...sending you a PM on engine mount question.
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.

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
If the impeller was completely gone, I would be more inclined to agree with the diagnosis that the water pump impeller broke apart. Normally when we are talking about water pump failure, we are talking about bearing failure. The bearing in this water pump is perfect. The fact that just the vanes are chewed off is what led me to conclude that the engine bits from the exploding case destroyed the vanes, and not vice versa. Truth is, there is no way to be sure what really happened. It's all water under the car now!!! the finger smiley

My two concerns now are how to adequately evacuate the cooling system of debris and will it be best to go with a OEM water pump vs. after market?
But both the OEM and aftermarket pumps with plastic impeller assemblies tend to fail by shedding vanes, leaving the impeller disc pretty much intact. As the result, the pump bearing does not die in the process. In the process of shedding the vanes, bits of plastic end up in small cooling passages in the heads, and perhaps more importantly, the oil cooler. If they sufficiently block the passages , steam pockets and cracking often quickly happens, followed by hydro locking and/or intermixing. If the oil cooler gets cut off from coolant, the oil temps skyrocket, particularly under heavy load conditions (e.g.: on the track), the oil breaks down (particularly 0W weight oils) leading to spun bearings, broken cranks, and a complete boat anchors where a perfectly good M96 used to sit. As I have mentioned elsewhere, your photos do not show the level of gouging type damage I would expect if something significant got into the pump area and tore up the impeller, your pump looks like several I’ve pulled out of street cars when the plastic impeller crapped out. I really think that you were happily belting around the track when some bits from your dying water pump cut off the coolant somewhere important, probably at the oil cooler, and the rest you already know.



Edited 1 time(s). Last edit at 01/03/2011 01:24PM by JFP in PA. (view changes)

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
Raby is seeing so many non-IMS failures that are water pump related he is recommending preventative replacements. There is no one making a metal impeller vanes pump. Raby thought of it but too expensive. He uses OEM, not aftermarket. This on $24k engines.

Cum grano salis.

Chacun a son gout.
From my diesel days of working on my boat the raw water impeller pieces would always be down stream in the heat exchanger area. If this was in a boat I could help but in a Porsche I'm clueless!!
and you should replace the oil/water heat exchanger the engine coolant passages will be free of any water pump impeller debris.

Sincerely,

MarcW.
I'd replace the oil cooler, the radiators and the heater core; it is often difficult, if not impossible to get all the debris out, and if some breaks loose in the future, well...................

“Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
If not then I agree with you. The old one should be replaced.

I'd back flush the radiators and heater core. Any debris should come out without any trouble. The OP should catch whatever comes out to try to get a feel for how much stuff comes out.

Also, I'd note the flow of water. If subdued or if it appears to be restricted, replace the radiator or heater core.

But otherwise, the back flush should remove whatever water pump impeller debris was caught in the units.

But of course it is always up to the OP. It is his car and he must do what he believes is right. An argument could be made that even a new heater core, and two new radiators given the cost of the whole operation, is insignificant.

Sincerely,

MarcW.
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