Water Pump and Thermostat

[Pdwight]

At some point in my future a new Water Pump and low temp thermostat is in my future now that I am almost 70K miles

My question is why are some water pumps advertised for $400 with composite impellers and there are some with metal impellers for 90 bucks ??

I could understand a 15% difference in price but not 300%

[JFP in PA]

Originally Posted by Pdwight

At some point in my future a new Water Pump and low temp thermostat is in my future now that I am almost 70K miles

My question is why are some water pumps advertised for $400 with composite impellers and there are some with metal impellers for 90 bucks ??

I could understand a 15% difference in price but not 300%

That's easy: You will replace the metal impeller units several times before you replace the OEM pump once. Metal impeller pumps also can be devastating to the engine cases when they start to wobble with wear. Do a search, been covered several times.

[Pdwight]

OK , Thanks ...in the BMW world ( I reside there also) the Metal Impeller pumps are what everyone uses to replace then the OEM units grenade...and they do often.

[Pdwight]

Are these Junk ???

Porsche Boxster 97 04 911 99 05 Water Pump w Impeller USA | eBay

[jdraupp]

If they weren't im pretty sure a lot more folks would be using them. My advice is to use an oem pump. Dont necessarily need the Porsche pump, go to pelican and get the kit with the low temp thermostat for 330 bucks. Youll have peace of mind knowing youve got a quality part keeping your investment from melting. Im not sure the water pump is a place you want to compromise.

[braszuca]

Hi.new here.just got my boxster 2000 25cdays ago i think the water pump is gon.going to try to replace my self.i di check the overflow tank, and is ok.after i park the car for couple minits i was able to see the dripping under the car just berrind the passenger seat.any one can help me with a link to show the best way.tks alot.

[DennisAN]

Many resellers discount the OEM Porsche water pumps. Here's one for $285. 2000 Porsche Boxster Roadster H6 2.7L Engine Cooling Water Pump - 99610601156 - Water Pump - ES#2224253

[seningen]

Originally Posted by DennisAN

Many resellers discount the OEM Porsche water pumps. Here's one for $285. 2000 Porsche Boxster Roadster H6 2.7L Engine Cooling Water Pump - 99610601156 - Water Pump - ES#2224253

Do not install any water pump with a metal impeller.



I would also seriously consider not using anything but OEM.

Get it from Sonnen, Sunset or Suncoast.

I once bought 6 ebay water pumps. Installed 2 in two cars at same time,
first one failed at 1K miles, second one did not actually fail - but I proactively removed it and it already had play in the shaft at about 300 miles.

I threw the other 4 in the garbage.

Frankly it's not worth the $100-$200 to play roulette. The OEMs aren't great,
but they seem to last ~30k miles.

I did read where someone was looking to put a wire mesh as part of the gasket --
this could catch impeller debris if it wasn't too small -- but I don't know if that
was just internet speak -- or whether the poster actually did it.

YMMV, but I only use OEM now.

Mike

[mavis.d]

Forgive my ignorance but what are the benefits of a low temp thermostat?

[Pdwight]

I have work on many different types of cars but this is my first Porsche, the low temp Tstat is completely open at 160 degrees and simply lets your engine run cooler. Cooler is always better on engines and the factory one opens partially at 185 deg...if I read this right.

[Brad Roberts]

The engine will NEVER run cooler than it currently runs. The Tstat does nothing to cool the car. It simply opens earlier. Nothing more.

Pierburg only for the water pumps. Gamble with the rest of the crap out there. See a good price on a water pump? Call and specifically ASK "what kind is it" If they cannot tell you? Then buy it from another source. DO NOT ask for the Pierburg. Ask them what they sell.

I'm fortunate enough to be 30min from the only authorized water pump rebuilder Porsche has in the USA. I've seen ALL the failures. ALL of them. Porsche actually comes to him 2-3 times throughout the year to go over the latest issues.

[Pdwight]

Looks like they can be had for under $250

Porsche Water Pump - Pierburg 99610601156 | FCP Euro

this is the first search I did. I will go this route when I do mine. Brad you are certainly a big help for us novices.

Thanks
Dwight

[mavis.d]

Originally Posted by Brad Roberts

The engine will NEVER run cooler than it currently runs. The Tstat does nothing to cool the car. It simply opens earlier. Nothing more.

Why fit one then?

[smitty986]

Originally Posted by mavis.d

Why fit one then?

If you want a very good explanation about low temp thermostats from an acknowledged expert do a search on the 911uk forum for LTT or bazhart.

[NewArt]

Braszucca, lift the mat under the coolant tank. Is it perfectly dry down there? Check the cap. The overflow hose runs down where you are describing.
Re: the low temp thermostat, I put one in and have noticed absolutely no difference in running temperature.

[Pdwight]

Well FWIW Brad is right, I was not thinking....I did this to my E36 years ago when I replaced the radiator and water pump and it runs in the same place...but I do have a little better peace of mind.

[JFP in PA]

Originally Posted by Brad Roberts

The engine will NEVER run cooler than it currently runs. The Tstat does nothing to cool the car. It simply opens earlier. Nothing more.

Sorry, but that is not correct. Yes the thermostat opens sooner, but in doing so changes the steady state operating temperature because the function of the stat is to set the minimum operating temperature.

It has been repeated documented by our shop and others that the steady state temp drops significantly, as does the oil temperature (often by 25F).

[Brad Roberts]

NO argument

Show me. Show me the test case, test scenario. I have 4-5 years of AIM and Motec data logs showing ZERO decrease in water temp. My logs are 25-30min logs and multiple 3-4 hr logs. With and without 3rd radiator, with and without BoxsterS water lines. With and without standard coolant (with/without water wetter)

I *know* you know better than to read the gauge for this. Show me


We are racing. I have steady state consistent lap times in all sorts of different weather. I'm suspecting what your seeing only pertains to certain circumstances.

[epapp]

The only time the low temp tstat would lower temps of the engine is when you are cruising on the highway and there is much more cooling capacity (because of a low ambient outside temp) than there is engine heat being transferred into the coolant. The tstat would stay open lower than the normal 186 and allow the engine to 'feel' the cooler coolant temps, probably stabilizing around 167, 169.

As soon as the engine starts putting out more heat than some specific amount (which isnt hard to do, in 90F weather my temps go up to 200 even at 70MPH), the lower degree tstat will just dampen the heat up cycle because of the coolant flowing around earlier in the heat up cycle.

City driving, hot weather driving, idling in traffic etc will all still produce the same steady state temperature, because the low temp tstat only allows wiggle room in the scenario that I described.

[JFP in PA]

Originally Posted by Brad Roberts

NO argument

Show me. Show me the test case, test scenario. I have 4-5 years of AIM and Motec data logs showing ZERO decrease in water temp. My logs are 25-30min logs and multiple 3-4 hr logs. With and without 3rd radiator, with and without BoxsterS water lines. With and without standard coolant (with/without water wetter)

I *know* you know better than to read the gauge for this. Show me


We are racing. I have steady state consistent lap times in all sorts of different weather. I'm suspecting what your seeing only pertains to certain circumstances.

For someone that says "No argument", you definitely come across as someone spoiling for one.

That said, I would fully expect that a 160F stat is not going to do much for a car being flogged on a track. First of all, racing is never "steady state"; on the track, everything is changing all the time (air temp, RPM range the engine is seeing, the number of cars holding you up at any given moment, load on the engine etc.), which only adds to the confusion when trying to reproduce results; and the thermal load conditions that car is seeing is totally different than that of a what street car sees. And as my comments are directed at street use, which is where the low temp stat was designed for, they do not apply to a car used in track applications.

On several customer's 986 (we done this with both base and S cars, Tips and manuals), fully instrumented (read not using the factory displays) when equipped with the OEM stat and running at a steady prolonged speed (target speed of 40-50MPH) with an ambient temperature in the 68-72F range, we have tracked coolant and oil temps over extended driving periods. Nominal coolant temps tended to be in the 210-215F range under these conditions, with the oil running 20-30 degrees or so warmer. With no other modifications, the same cars produced steady state coolant temps of 175-180F by switching to the 160F stat, with a concomitant drop in the oil temps as well.

Will the street driven car heat up and turn the fans on if it gets stuck in traffic? Yes it will, but it will take it longer to do so, and will cool back down to the lower observed steady state temperatures once air flow over the radiators comes back and the car returns to cruising speeds.

So does using a 160F thermostat result in lower coolant (and oil) temps on a 986 driven on the street? Most definitely. We have also tracked UOA's on some street cars, before and after they were switched to the 160 stat, and observed slower oil degradation over time, which is probably attributable to the oil seeing consistently lower temperatures as well.