gpjli2

Current CR blackballs 06 997, not for major engine problems (the IMS failure that we all obsess about), but for "engine cooling". I searched this and other forums for evidence of water pump/cooling failure without any luck. There is an article by Jack Raby who recommends WP replacement at regular intervals (3-5 years) to avoid engine failure resulting from detonating water pumps. For those of us planning to keep our cars past 5 years or more then we should know about Porsche and water pump failures. Since it seems a replacement can cost 1000$ w labor and fluids it is not to be undertaken lightly. There also is a question regarding plastic or metal blade units believe it or not. Any one out there that can shed any light on this issue? Any high milage pros like Mac or others had first hand experience here?

cvazquez

1- Recommend not using distilled water or diluting the coolant with H2O
2- Stay with the Porsche coolant concentrated version type coolant
3- Add Wet Wetter from Red-Line to top off system
4- If replacing water pump get the Porsche and not generic water pump. Also change thermostat to Pelican low temp thermostat. I did on the Boxster and can see that its running cool. I can also attest to this because I've tracked the Boxster during June at Sebring Florida

gpjli2

I've read that OEM unit is the way and also to specify metal gasket. Find it strange that CR's P drivers have reported hi #'s of cooling failures and you don't read much on the boards about it. Thanks for the advice.

Macster

Well, I hate to disagree with Jake regarding his recommendation based on what's he's seen. Thus I would not dismiss his recommendation out of hand.

I do not have a number of cars to go on: All I have to go on is my experience with my 02 Boxster. Well that car and other cars I and my family and friends have owned, but even so not nearly as many cars as Jake has seen.

As an aside: The only water pump I can remember going bad besides the one in my Boxster was my sister's Camaro (I can't even remember the MY now) that developed a bad water pump which I replaced for her.

My Boxster's water pump lasted over 170K miles and didn't come apart but got noisy, and it was a very subtle noise too. Took some effort just to id it was coming from the accessory drive area and not from inside the engine.

By removing the belt and starting the (cold) engine I confirmed the noise was not inside the engine.

Then a wiggle test of the various idlers/tensioner rollers and accessory drive pulleys id'd the water pump as the likely source of the noise. Of all the accessory drives it was the only one that exhibited any play. And not much. I had to go around and test each drive pulley several times to be sure.

Also, the relatively new belt had a sharp (inside) edge on it too which indicated a pulley was slightly out of position and the belt was rubbing. The water pump has some white residue on its casting that looked like a coolant leak so I had the pump replaced. My 'guess' proved to be right. The replacement pump has nearly 80K miles on it.

Later, techs told me the water pumps can leak a tiny tiny amount and still be ok. Porsche issued guidelines (to the techs) that describe the location, size of the stain of white residue. I asked but the techs refused to share the guidelines with me. They did offer that there should never be any signs of liquid coolant.

Anyhow, if one is not attentive to his car's sounds a noisy pump can escalate into one that comes apart.

Based on what I have seen there's not a lot of clearance between the impellor blades and the cavity in which they whirl about. Any clearance represents an internal leak which lowers the efficiency of the pump.

If the pump bearings become bad, develop play, this can allow the shaft to be pulled out of position by the tension of the belt. I note because the belt had a sharp edge the pulley was already pulled a bit out of position and since the impeller is of course attached to that same shaft it must be out of position too. If it gets far enough out of position this can result in the blades contacting the engine casting and the blades will almost certainly break.

And not just a tiny bit. This can quickly go nuclear and the pump can lose all of its blades.

The water pump quiets down, spins just fine, but does not push any water through the system. Trouble ensues.

My (admittedly informal) automotive mechanics training, such as it was, was by professional mechanics and what I picked up from them was to let the car or the engine tell you what it needs.

One can spend a fortune on replacing components based on some time or miles number. There is also the risk the new component can be bad, prematurely fail.

IOWs, let sleeping dogs lie.

OTOH, this was years ago and for was mainly based on the mechanics' experience with USA cars like Chevy, Dodge, Ford.

Must point out too that Mike Miller who writes for Bimmer mag strongly advises preventative water pump and IIRC even radiator replacement for BMWs. I won't make this post any longer by saying why I agree with him, but I do.

Back to you: What to do?

I can't say other than you have to make up your own mind and do what you feel most comfortable doing. I'm willing to I guess roll the dice a bit and to continue to do what I've done and so far it has worked just fine for me.

But my method may not work for you: I might just be lucky. One thing that occurs to me is I'm rather attentive to my cars' behavior and sounds. Thus I am more likely (I hope) to spot things before they turn nasty/serious. If you're of a similar type... you might do as I do. However, if you're the type of person nasty/serious car problems seemingly come out of nowhere you might want to adapt some preventative component replacement program. No shame in that. We're all different. I can't pick stocks.

As for a low temp t-stat... I don't know. Again I hate to disagree with Jake but I did an experiment with my Boxster last summer. With a data logger in the car I took it out for a spirited drive in the mountains around my area. It was a rather hot day and the coolant temp at times reached 226F. (Oh, I had the A/C off too.) Of course the radiator fans came on. I purposely pulled over to the shoulder rather than keep driving to see if the coolant temp would climb any higher. It did not. While I sweltered in the heat (A/C off remember) the coolant while for a while was at 226F it never got any higher. Once moving the coolant temp quicky dropped to around 200F.

The (replacement but factory) t-stat in my car is a 190F t-stat; which is I believe the temp at which it opens (I always test t-stats before installing them, but I suspect this one was just unboxed and installed when I had the water pump replaced) and I note that early in my drive the the coolant temp quickly rose to over 190F and said t-stat was fully open at this point.

Thus I do not see how a lower temp t-stat in this case could have helped any.

The limit to how cool the coolant is kept is the car's cooling system's rate at which it can shed heat.

It occured to me that one thing that one could do would be to add more cooling capacity: more radiators (a 3rd radiator -- which I note is what Porsche does when it wants a car with more cooling), larger radiators, or come up with a way to run the radiator fans on low speed all the time of course without interfering with them being run at high speed if the coolant temp ever climbs above 216F (which is the temp my info says at which the fans are switched to high speed).

I note my Turbo runs quite a bit cooler than my Boxster. The Turbo while it has a more powerful engine has a 3rd radiator. I do not know if the radiators are bigger. The Turbo's aerodynamics are better: The car flows more air through the radiators. It takes some heat to cause the fans to come on.

Again, what to do. I'm loathe to drop in a lower temp t-stat. I've covered alot of miles and my cars have seen some real hot temps; back in 02 (July) 116F in the Boxster in southern AZ and the Turbo a few years back went through some 119F temps in northern AZ (note to self: stay the heck out of AZ in the summer!); and neither car suffered any because of the heat.

I don't have it handy to quote from but I came across a chart that listed various engine temps and wear rates and below 200F wear rates increased. I know heat is the eneny of engines but some heat, not too much, but some just enough, can be quite beneficial and promote engine longevity.

So. Do it? Or don't do it?

Sorry, but you'll get no do it or don't do it from me. Just listen to all inputs, think about it, and make up your own mind so you will chose a course of action you feel you can live with.

Sincerely,

Macster.

Jay H

Keep in mind that these vendors that write articles are also selling replacement products... The vendor you mention above is very knowledgable on the M96 motor...but Porsche has a larger R&D section than these vendors. Take what you read with a grain of salt.

Macster's writings hit the nail on the head (as usual). Be attentive to your car. Listen and inspect or pay a knowledgable tech to go over the car at regular intervals.

I would not start replacing parts before their design life is up just to replace parts... You can sometimes cause other issues by messin' with a very good part that does not need attention.

gpjli2

Thanks for the perspective gentlemen. I am a "don't fix what ain't broken" believer in general. At 6 years and 30K miles I will keep my ears open. Preventative maintainance is a slippery slope

irish guitar

My '06 went south at about 26k miles. The were telltale noises in advance.

McCulla

Had the water pump replaced on my 05 997 at about 30K miles. Leaking.

No HTwo O

I asked Sunset Porsche about this last year, and here is what the parts guy told me:

2010
997/987 water pumps sold- 9
996/986 water pumps sold- 71

2009
997/987 water pumps sold- 5
996/986 water pumps sold- 53

I may replace the water pump in my Boxster this fall after the driving season when I also plan to do an early coolant flush and replace the serpt. belt. I think an OEM pump is only about $200.

FiatCoupe

Water pump on my 2007 C4S wore out at about 50k miles. Tell tale signs were that the water temperature would start to creep up past 175 when sat in traffic. Water temp was okay when moving. No leaks. Fixed under CPO warranty but was told typically they are about $1600 to replace.

McCulla

lucky I had my replacement done under my extended warranty, I remember a figure north of $1000.

Luxter

Have a look at this site and read buyers guide #5 in particular.
http://www.hartech.org/buyers.html
It is a long read, but ... it also deals with 160*F T-stat and why it makes sense to have it installed in certain situations.
Far more info than LN Eng. web site and well documented. Engine thrust sides, changes to head gasket, overall condition of coolant, etc, etc.
I just replaced my water pump, installed 160*F T-stat and added 3rd rad.
And going to replace coolant with fresh mix. Mind you after almost 7 years of service coolant looked not too bad at all.
Cheers,
=L=

rickmdz

My water pump was replaced under warranty at 36k miles last year. Porsche tech told me it was a fairly common failure in these cars. My car is a 2006 C2S.

aaks38

anyone here know whats involved in replacing the water pump, ie does the engine have to be dropped or can you access everything by maybe only having to remove the rear bumper cover?

Spokane5150

All car and motorcycle manufacturers design their engines to run at a specific temperature to meet EPA Standards. Even boats and lawnmowers are starting to take pollution standards in mind when designing motors. That's why 2-stroke motors are going away. In order run efficiently, the engine needs to run at a specific operating range to burn off unused gases. You start trying to drop the temps outside the efficiency range then you're asking for problems in my opinion. If you've modified your engine and you're running more HP and you're on the track a lot then you may need to add a radiator or somehow improve cooling especially if you're still running a stock motor. All the sensors, cats, emission controls and ECU are designed for a specific temperature. There is major science behind operating temps for these cars (not race cars) and the way the intake flows and the way the exhaust gas flows during operating temps. If you try to lower that temperature then I think you could take the chance of losing efficiency and ruin some of your emission devices like catalytic converters. I'd add/improve a radiator if I was overheating but that's about it. Debated subjects below:

See link:

http://autos.yahoo.com/maintain/repa...ques019_2.html

http://www.lnengineering.com/lowtemp...hermostat.html