roperin

I replaced my water pump at 42,000 miles, it was ok even the bearing was ok. I bought a metal impeller pump replacement part from DC Auto and it looks good, it was made in Stuttgart, so i thought that was good news. IT'S BEEN IN THERE FOR 6,000 miles now and so far so good. It was about $106 , cheap. I replaced it because I was seeing higher temperatures in summer but it was the damn hose, tiny pinhole where the hose has a 90 degree turn.

sandersd

If your bearing does ever fail, the metal vanes on the impeller disk might not shear off as they did in mine without taking chunks of the block with them. I think I prefer the plastic impeller OEM pump for that reason, even if it does cost $150 more than a cheap one.

Hope yours holds up well.

Dharn55

Here is a diagram of the coolant flows. Not too detailed but it might help.https://rennlist.com/forums/images/attach/pdf.gif

sandersd

Service manager at dealer says no issues with blockages as the vanes are chopped up into really fine pieces when the pump goes and are distributed throughout the system. Also Porsche has no procedure for flushing system as a result of water pump impeller damage and advised it is safe to install new pump.

Be nice if the pieces were not there but realistically, short of disassembling the entire system for cleaning and inspection, there's no way to remove them.

Flat6 Innovations

Really? Ask him how many cracked M96 heads he has personally repaired. Follow that question up by asking him how large the capillaries inside these cylinder heads are at their smallest points.

Just like they NEVER have a mileage or time in service replacement for these water pumps. Everything that the dealer offers was a PROJECTION when these cars and engines were new, what actually happens in the field isn't taken into consideration.

You must do what is required. The engines that we see here with intermix have almost always had a new water pump installed just a few weeks or months prior to the cracked head episode that lands them here. SOme disassembly is required and beware that these tiny pieces can easily collect inside the capillaries of the cylinder head and lead to a localized hot spot that then leads to a crack that will propagate between the oil and coolant passages and lead to intermix.

These jobs are never repaired by the dealer, because this sort of intervention is not recognized at a dealer level. They will only recommend "engine replacement", so they generally do not understand the dynamics of the episode.

Their is a way to avoid these issues, but it takes effort and getting dirty. Trust me, you can't afford NOT to remove those pieces. This year we have seen more engines die from this than all other modes of failure combined, to include IMSB failure.

sandersd

So what is your recommendation as to what must be disassembled? How far does one go?

sandersd

No comment?

wyovino

Here comes the Water Pump Guardian

Jake - just to clarify: When you said that most engines with intermix problems had recently replaced water pumps. - do you mean water pumps replaced due to failure?

KNS

I think Jake is saying that after suffering a water pump failure the car is put back on the road with a new water pump (and without getting any old bits of the previous water pump out of the engine).

With those little pieces still in there, the engine soon after gets a cracked head having nothing to do with the newly installed pump.

Dharn55

I agree with Jake that if the impeller has disintegrated the pieces can cause real problems in the engine, and the heads in particular. In the case of my intermix in2008 the pump impeller was intact,so the heads do crack from other causes.

I think you would have to remove the heads and back flush each of the passages, which would require knowledge of exactly how the passages flow. As there are multiple paths of coolant flow just back flushing the system in general probably won't work. Not sure if this can be done with the heads on. Then also back flush the cooling passages in the engine block itself. You want to make sure no pieces are left where the coolant flows from the pump to the heads. Probably want to flush out the rest of the system, pipes, hoses, radiator, tank, in case any pieces made it through the larger passages, they could get recirculated and end up in the heads again.

With all this it sure seems like replacing the pump every 40,000 to 50,000 miles is a cheap preventative maintenance routine.

As with many of the means of failure in these engines, they may only happen with a small percentage of engines, but if it is yours it really hurts. And if you think about it, if only 3-5% fail due to water pumps, and the same due to IMSB, and the same for chain failure, and for cylinders going oval, and for liners slipping, etc.etc., this could lead to a significant percentage of failures overall. IMHO!

sandersd

With all due respect this is all just anecdotal evidence. Maybe it will cause problems and maybe it will not, but one would have to do controlled studies to confirm objectively. Since Porsche has no contingency for this type of failure one could assume complications to be negligible. Agreed if it happens to me it will certainly be unfortunate.

The pieces could have been blown out under pressure with the coolant so my concern may be unnecessary. If I assumed there were pieces lodged in the heads, even if the engine were cleaned some debris could have lodged in other places, only to work loose later. One would have to completely disassemble the entire engine and cooling system and visually verify all the pieces were removed to be sure. Who's going to do that? Replace the radiators? They certainly can't be inspected.

I'm not going to disassemble the engine and cooling system. I could never justify the expense to pay someone else to do so, even if it were a realistic option. It's a risk I am forced to accept. Whatever happens, happens. C'est la vie.

Flat6 Innovations

Sorry, wasn't around the computer.. Putting together an R&D trip together... 6,000 miles in 10 days with a two day class thrown in the mix in Alberta Canada..

Other than removing the coolant console at the front of the engine and retrieve as many pieces as possible, there isn't much more you can do at home.. Worry less about the radiators than anything else.. You want the crap to stay out of the heads at all costs. The issue is the coolant path takes the debris straight to the heads from the impeller housing. A cooling system "Guardian" is already available and we use the arrangement on our turnkey engines.

In my M96 complete mechanical classes and M96 Engine Rebuild school we hear a lot of stories about this coming from other shops as well. The issue is the worst on 2000 and 2001 models, by far. I'll post some video on our facebook page tomorrow, if I get a chance..

Shark Attack

wrong type of anti freeze over a period of a year or two. American AF breaks down the plastic in the system. It makes is soft and breaks easy

seanmcr6

whoah whoah whoah.....two day class in Alberta? When is this? Where is this? how do I get in on this?

sean

chsu74

Why don't you piece the propeller together and see size of missing pieces before chasing yourself into a frenzy?