Water Pump

[cvhs18472]

My 98 Boxster is very quickly reaching 60K and I would like to replace the water pump this winter. Is it worth paying the vast difference to get the pump from a dealer, or has anyone had good luck with an EBay seller. Thanks in advance for you thoughts. Ed

[JFP in PA]

Considering the amount of work you are going to have to do to replace it, why not give Sunset Porsche a call (they are the lowest cost dealer out there) and get the correct one. Would also be a good time to swap out your T-stat with a 160 F unit……………….

[23109VC]

what is the benefit of doing hte 160 degree thermostat?

does it make the car run faster by making the car run cooler? i've heard of guys claiming that on other cars.... but h aven't heard any definitive proof that it does that...

if the car runs better/faster/more efficieintly/etc on a 160 thermo why didn't Porsche put one in from the factory?

[JFP in PA]

Originally Posted by 23109VC

what is the benefit of doing hte 160 degree thermostat?

does it make the car run faster by making the car run cooler? i've heard of guys claiming that on other cars.... but h aven't heard any definitive proof that it does that...

if the car runs better/faster/more efficieintly/etc on a 160 thermo why didn't Porsche put one in from the factory?

Besides potentially saving your engine by keeping it cooler, as well as substantially lowering oil temps ( a HUGE plus); yes is makes slightly more power by improving volumetric efficiency to the tune of picking up 5 HP. LN Engineering, who developed the 160 F stat in conjunction with Jake Raby, has data from dyno pulls on their website……………..

And Porsche does use lower temp stats in their "performance" engined cars such as the GT2, GT3, and Turbo cars................

[jmatta]

I have the 160 LN stat in my Box S, so I'm biased. This has been debated many times on this and other forums, but the bottom line is the car's coolant temp is reduced by some 20+ degrees, thereby reducing oil temps at the same time.

As for why Porsche didn't design this like the GT3s, turbos, etc?
I think the answer lies in that the typical use of a US Boxster driver is shorter trips as a daily driver vehicle. The higher temps help burn off containiments in the oil, at the cost of higher heat, oil breakdown and engine wear. JFP, Raby and Navarro have dissected these engines and know their faults and weaknesses...I trust their judgement in the "everyday" real world.

I want my engine to last a long time (I'm approaching 16k miles). I change my oil at least annually (3k miles) and use only high quality synthetic and OEM Porsche coolant.

If I were changing my water pump, it wouldn't be with some knock-off.

[Franco]

Hi, I replaced the crappy OEM pump with one bought on ebay, it has been 2 years since and haven't had any problems.

I paid about $125.00 shipped.

[Lil bastard]

I have to disagree with those urging oem replacement.

While I usually always go oem, the waterpump is simply inferior to several of the remans or aftermarket ones out there using a metal impeller instead of the oem plastic one.

Not only is coolant flow reduced and debris forced through the system (possibly clogging it) as the impeller degrades, but it also throws the shaft out of balance shortening the life of the bearing, seal, and the pump itself.

The pumps with metal impellers don't cost any more, in fact, they're usually less than oem.

[cnavarro]

Originally Posted by JFP in PA

Considering the amount of work you are going to have to do to replace it, why not give Sunset Porsche a call (they are the lowest cost dealer out there) and get the correct one. Would also be a good time to swap out your T-stat with a 160 F unit……………….

If you call Suncoast, they carry the low temp thermostat as well. One stop shop if you did want to go that route.

[gschotland]

I recently purchased an OEM pump from Suncoast for about $200 delivered. A good enough price to make me not think much about the $70-80 "savings" buying one from an iffy seller on eBay.

[Lil bastard]

Originally Posted by gschotland

I recently purchased an OEM pump from Suncoast for about $200 delivered. A good enough price to make me not think much about the $70-80 "savings" buying one from an iffy seller on eBay.

Sorry, but IMHO, the 'iffy' part is the oem replacement.

[pk2]

Originally Posted by JFP in PA

... Would also be a good time to swap out your T-stat with a 160 F unit……………….

------------------------------------------------------------------------------------------
I always thought tolerances in an engine were optimized to operate best at a specific, predetermined temp. Motors are made of lots of different alloys any metals. They all expand at different rates. In this case, the state of the alloys at 180 degrees is where the engineering is done and optimized.

Just in a piston and rod assembly, you have 5,6...10 (?) different alloys all expanding at different rates and amounts as they heat up. The engineers decided 180 was nice and designed the parts, taking into account they're expansion, to fit best when they are all at 180. At 160, your goung to have different tolerances. Maybe the rings have expanded but the cylinder hasn't caught up, more compression, more hp, what ever. But harder on other stuff that's not fitting right. Of course far to be it from me preaching tips for longevity, I've disregarded all common sense pushing mine towards a D-chunk.

I could be totally wrong, after all you don't really have to warm up a car any more. But, justifying this change because a GT runs at 140 is apples and oranges for the reasons above. The engineers liked 140, for whatever reason, and designed everything to fit best at that temp and the accompanying degree of expansion of the various alloys etc.

Aside from that, the GT and Turbos are entirely different engines. Water cooled flat sixes yes, but I believe they were derived from the 959 which was based loosely on the old bullet-proof, air cooled 963(?).

I'm not saying don't do it, with a good explanation, I might even do it myself when the time comes. I'm only saying I doubt that the 180# was an arbitrary # for this motor. Probably very minuscule, but I don't think you do it without some long term consequences.

Coffee's gone, Saturday sermons over.

Regards, PK

[jmatta]

Jake and Charles have shown that the M96 engine actually operates at around 210*, not 180*. The factory t-stat doesn't even open until 185* and isn't fully open until around 205*. The LN stat opens at 160* and is fully open by 180*...cooler coolant and cooler oil; makes your engine last longer.

As far as the water pump; if I ever have to replace mine, I will compare the options and purchase the best replacement part regardless of cost.

[pk2]

jmatta

In all sincerity, why would Porsche knowingly put a thermostat in that they must know (if you do) is much hotter and is therefore going shorten the engines life ?( As if the motor wasn't a bit of a disaster as it was.) And if it's running at 210, why not say so instead off consciously papering over the dash gauge to read 180?.

Do you think they play the same hi-jinx with the GT and turbos that, as is stated in this thread , are supposedly running at 140?

Also , cooler oil sounds nice (especially on a hot day (grin)) but what difference dose it make...it breaks down sooner and might be harder on rubber seals but what else that isn't compensated for? These things have a pretty aggressive oil change regiment which should mitigate any oil degradation, and rubber seals arn't your fathers

This isn't rhetorical and I'm not being a smart a__, I'm truly curious.

Regards, PK

[Lil bastard]

Originally Posted by pk2

jmatta

In all sincerity, why would Porsche knowingly put a thermostat in that they must know (if you do) is much hotter and is therefore going shorten the engines life ?( As if the motor wasn't a bit of a disaster as it was.) And if it's running at 210, why not say so instead off consciously papering over the dash gauge to read 180?.

Do you think they play the same hi-jinx with the GT and turbos that, as is stated in this thread , are supposedly running at 140?

Also , cooler oil sounds nice (especially on a hot day (grin)) but what difference dose it make...it breaks down sooner and might be harder on rubber seals but what else that isn't compensated for? These things have a pretty aggressive oil change regiment which should mitigate any oil degradation, and rubber seals arn't your fathers

This isn't rhetorical and I'm not being a smart a__, I'm truly curious.

Regards, PK

Well, 60% of the heat produced in the engine (and some of the most critical heat, think bearings) is carried away by the oil, not the coolant.

In the Boxster, the heat exchanger transfers much of that heat from the oil to the coolant which dispels it from the radiators.

So, if the coolant runs lower temps, it does a better job of aiding the oil in shedding the heat.

[jmatta]

pk2, if you are curious, do a search on the topic. The merits of the t-stat have been debated time and again. The temp reading on your gauge is a joke.

Porsche is more concerned with burning off oil containiments (for those extremely long oil change recommendations) than engine longevity, hence their choice in operating temperature.

[Blue-S]

Some people seem to think that the Boxster cruises at 180 degrees because the temp gauge needle typically sits between the "8" and "0" of the "180" label when at cruise. I don't think that Porsche labeled the gauge so that 180 degrees is indicated when the needle is in that positiion...even if they might have made it deliberately misleading. The temp gauge has a blue-tinged tic in the vicinity of the "100" label, then an unlabeled tic, then a tic above the left side of the "8" in the "180", then another unlabeled tic, and finally a red tic in the vicinity of the "250" label. That being the case, the common temp gauge needle position at cruise (between the 8 and the 0) might be inferred as 200 or maybe more. I suppose that the unlabeled tic to the right of 180 could be inferred as 225...

The Boxster engine actually runs above 200 degrees at cruise, but (in stock form) has a 180 degree thermostat. This is possible because the Boxster's thermostat is on the INLET side of the cooling system. This is made clear by the cooling system diagram on page 19-2 of the Bentley service manual. So if the coolant returning from the radiators has to exceed 180 degrees to begin opening the thermostat, then the coolant leaving the engine (headed for the inlets of the radiators) must be significantly hotter than 180 degrees...and that's why an engine with a 180 degree thermostat actually runs in excess of 200 degrees at the temperature sensor location. This also explains why the 160 degree thermostat can result in cruise temps in the 170s - 180s.

[pk2]

Jimatta, Lil_bastard, blue-Thanks for your interest.

Jimmata, As far as an “ongoing debate” about water temp, I’ll check it out. If there’s anything definitive (Blu_s seem plausible), I’m in. If it’s another XYZ headers vs. stock, K&N vs. stock filter vs. cold induction …bla bla bla…and they all the add hp… I’ll figure it out, not that hard to take an accurate coolant temps.

(Blue_s) Interesting facts. With temps all over the place from heads to block to radiators, could the 180 on the dash just be a calculated average of pertinent areas?

But (lil_bastard), I just cut to the chase and got a read on the oil temp in my car (seems to be the real issue). Unless someone finds fault with my methodology, mine is 188f… under pretty harsh conditions. Don’t know if 188f is good or bad or how closely it’s linked to coolant temp. I’m confident it’s pretty accurate, and from what you’all say, it is the real bottom line.

Anyway, below are picks of my little measurements..
Details of methodology are below pics.


By Kroak

I drove moderately hard about 4 miles with a few final full boost red lines, gauge read 180, ambient temp 97f (if not on fire) and dry, 22% humid, asphalt 157f (proximity to oil sump, might matter). Intake temp 175f (forced induction, Eaton M63)*, internally stock original 2,.5L, 32k, an extra 50-80 hp (depending who you talk to (like these threads)) but, a significant extra load worth mentioning.

To measure the temp I used a laboratory digital laser pyrometer and pointed it at 1“ from around the middle of the bottom of the crankcase. Most all the oil, cooled, or back from circulation should be there after a short rest (3mins.). Plus aluminum is a very good conductor of heat; After 3 mins. Oil inside should be about the same temp as the bottom of the case I figure.

So I don’t know, if my methodology is right, is 188f to hot for the oil under somewhat extreme circumstances, what should it be?

Regards, PK

* I only took 1 reading on the blowers exhaust to intake pipe@175f . Like to take 5 or 6 to verify accuracy & repeatability but, trust me, it’s frigging hot..

[JFP in PA]

Sorry, but while your "experiment" was at a minimum "entertaining", it did not give you a single accurate reading of the circulating coolant temps, which are much higher. From the factory, the M96 coolant typically runs between 210-215F when the dash gauge indicates 180 (the dash gauge is both inaccurate and non linear in its function), measured by the actual sensor in the coolant, which is pretty accurate when temperature tested out of the car. Changing the OEM thermostat to the LN 160 degree unit lowers the engine coolant and oil temps significantly; the coolant to 175-80, the oil by as much as 20-25 degrees. Oh, and rather than use a non contact infrared pyrometer to "attempt" to determine coolant temps, we also actually added aftermarket instrumentation (calibrated gauge units) to confirm the numbers, which they did. Getting the oil temps is a bit more complicated, requiring adding a remove oil filter mount to accommodate the test instrumentation.

If you really want to know the temperature of your coolant, connect a OBD II scanner with PID capability to your OBD II port and set the unit to coolant temperatures; then take your car for a ride. Under cruise conditions with a ambient temperature in the 70-73F range, let us know what you find…………………
…you just might be surprised as well................

[pk2]

JFP_PA,

Glad to entertain. I'm all for running cooler.Indeed, I'm on the verge of h20 injection/intercooling. But as blue_s stated, the reason for allegedly running it hot was to burn off oil (theory?). We have the most stringent emissions standards in the land...might not fly.

But, the point made here several times is you want your coolant cooler so the oil is cooler. Well, they don't seem so directly related. Obviously my oil temps of 188f (assuming good methodology) are lower then the 210 every body is talking about & the oil has it's own cooler (no?). So again, begs the question,Forget the water, How hot should your oil be?

The Digital laser pyrometer can indeed be "entertaining" at frat parties especially, drawing a laser bead on your friends crotches and zapping temp readings...laugh riot. But actually, it's a very accurate scientific instrument. I snagged it straight from the family biz/laboratory's where it's used daily while they accelerate, smash and other wise mess with atoms and ions at thousands of degrees and at the speed of light(not exactly frat. stuff). Also, can't think of a better place to take a read, can you?. (if ya do I'll do it).

Anyway you make some good points. OBCII reading sounds interesting, I'll try it. but you realize your taping into a pretty primitive sort of sensor, electro mechanical, through Porsche's apparently less than honest electrical system.

You'all are probably right, you've made some compelling arguments.... And god knows I can use all the cooling I can get. A blower generates lots of top end heat (I know, have 2 EGT sensors). But, so many people swearing they feel the unsubstantiated but advertised 5-10-15 hp with their new ebay headers, greasy air filters, what ever. Ya gotta be more skeptical the more logic is defied. So when someone here said the thermostat is good for another 5 hp...Ya gotta think "oh god, here we go". But as the science trickles in it seems compelling.

Thanks again, PK

BTW; In my BMW3.0 coup days, we used to just drill holes around the perimeter of the thermostat. They were really accessible so trial an error was easy.

[Blue-S]

Originally Posted by JFP in PA

From the factory, the M96 coolant typically runs between 210-215F when the dash gauge indicates 180 (the dash gauge is both inaccurate and non linear in its function), measured by the actual sensor in the coolant, which is pretty accurate when temperature tested out of the car.

When you say the dash gauge indicates 180, where is the needle pointing? Is it straight up, between the "8" and the "0"? I contend that the tic mark above the "8" is the 180 degree position, and the common cruise position (straight up, between the 8 and the 0) is intended to indicate HOTTER than 180 degrees. The gauge is certainly non-linear, and was apparently not designed to provide a precise temperature indication. If they had used a more serious-looking font, maybe they could have placed the number markings in a centered position below each respective tic mark. Maybe they should have just left the numbers off of the gauge altogether...