The biggest "trade off" in that article is that it assumes (incorrectly) that the car is going to take longer to warm up leading to additional engine wear, which simply isn't true. Cold starts in a situation where oil takes forever to circulate can result in some level of increased component wear, but the assumption is that the oil is not going to be able to do its job, which would only be the case if high single weight non synthetic oils are involved, or if there were some organic issue with the car's oiling system.

If you step back and think about it, when an engine running 5W-40 oil lights off on a 30F morning, which thermostat is in it is irrelevant as neither would be circulating the coolant at that moment, and the component wear rates are a function of the oil, not the thermostat. As the car with the 160F stat reaches 160F coolant temp, the coolant starts circulation to the heater and the oil cooler, where it warms the oil, helping it to do its job more effectively (take a look at the recent thread about which is more important in an engine, oil temp or coolant temp) . Because the 160F stat is open sooner, the common owner comment is that the car warms up quicker, which is more of a perception that a real fact due to movement of the temp gauge and more cabin heat sooner. In reality, up to the point where the 160F stat opens, both a 160 stat car and a 186 stat car were warming up at the exact same rates, so there is no actual difference in component wear. But because the 160 car is now warming the oil up to operating temperatures, the oil should be circulating more easily and warming up the critical lubricated components.

We have a lot of customers running the 160F stats under all kinds of climatic conditions; I have had the privilege to see the insides of several of these engines and have not seen any evidence of increased wear, sludge build up, high levels of fuel contamination in the oil, or any of the legion of other low temp stat related bugaboos that some people claim result for using them. And as we offer customers UOA's as part of their regular service, I have seen a lot of test results confirming that the oil is happier when the 160F stat is in the engine.

Probably one of the most telling points on the 160F stats is that Porsche uses them as the OEM stat in their max effort engines (Turbo, GT2, GT3). It is also interesting to note that the very late model Boxster and Caymans run a new "thermal management system" in place of a conventional thermostat that keeps the engines cooking at over 225F until you put your foot down, then the system switches to try to quickly lower the coolant to around 185F for as long as you keep your foot in it; then when you lift, the system takes the coolant back up to 225+F. You can read all about this new system in Porsche's own literature on the late model cars.

So as I asked in my poll thread. Porsche designed a new water called engine in the 90s and did not separate the heater circuit from the radiator circuit (thermostat)?

Yes, we have seen this both on cars with full instrumentation (after market coolant and oil temp gauges), but have also seen it using PID scanners as well.

The steady state I refer to is the equilibrium temperature the car settles at when running at a steady highway speed (50-60MPH) on an average day (say 68-75F air temp). I think that you are overlooking the heat transfer capacity of the cooling system in these cars, and the throttling effect of the stats; stuck in traffic, a car with a 160 stat will eventually get warm and kick the fans on, but it takes longer than with the 186 stat. Once either car gets moving, both will settle back to a steady state condition, with the 160 stat car settling at a lower temp (usually around 175F or so). This is the impact of the heat transfer capacity of the cooling system. But the car with the 186 stat settles at a much higher temp, often north of 210F. If you put both a 160 stat and an 186 stat in a beaker of heated water as I mention earlier, you would note that at around 170F the 160 stat is wide open, while the 186 stat is still closed. As the water gets hotter, eventually the 186 stat starts to open, but is not fully open until well past 200F, restricting the coolant circulation up to that point; so it is "throttling" the coolant flow. So even though the car has the capacity to transfer the heat out of the engine at steady state, the throttling of the 186 stat restricts the coolant flow and keeps the coolant hotter at the same speeds and air temps.

The inaccuracy of the dash display is actually two fold; it is inaccurate across much of its "band width", but it is also non linear (it does not "sweep" equal amounts for an equal amount of coolant temperature change). On a car showing 180 degrees on the dash, it is not unusual for a PID scanner to read 210F, yet both the scanner and the dash are getting their information from the same sensor in the engine. In essence, the temp display is little more than a "not over heating/over heating" idiot light replacement.

Thanks for the great explanations Jeff. Makes perfect sense to me.

http://pic Hi, i believe my water pump on my 986 is bad, lost allot coolant last friday temp. indicator was blinking, checked underneath and suspected the water pump, there's allot of stain around the hose under the pump. pressure checked it to about 10-15 psi but no leaks visible. also noticed when the engine temp get to about 186 deg. the engine blower doesn't come on then about 200 deg. the radiator fan on both front comes on. thinking about doing this water pump and thermostat replacement on my own. did you have to remove the front engine mount to replace the water pump?
where did you get the parts?
Thanks
Ferdie

We are a shop, so we have parts deals through multiple sources. While removing the engine mount is not necessary, many doing this on the ground find it gives them better access.

Water pump/ thermostat
 

Hi, i believe my water pump on my 986 is bad, lost allot coolant last friday temp. indicator was blinking, checked underneath and suspected the water pump, there's allot of stain around the hose under the pump. pressure checked it to about 10-15 psi but no leaks visible. also noticed when the engine temp get to about 186 deg. the engine blower doesn't come on then about 200 deg. the radiator fan on both front comes on. thinking about doing this water pump and thermostat replacement on my own. did you have to remove the front engine mount to replace the water pump?
where did you get the parts?
Thanks
Ferdiehttp://986forum.com/forums/uploads01...1370206897.jpg

water pump
 

bad water pump? http://986forum.com/forums/uploads01...1370207475.jpg

Possibly, I would also replace all your hoses and clamps too.

Thanks I'll do that, i took off the belt and moved the pump wheel and there's a movement and rattle
i'll order the parts tomorrow at pelican. and prep it for replacement i'll just leave the engine mount. I think I can replace it like that.

While you're in there, you should replace the engine mount. I haven't done mine yet, but wished I did when I recently did my water pump. The engine mount is about $130 i think or you can just buy the rubber insert which I think is $35 and press the old one out and new one in. I hear it's a good maintenance item to do.

Also, not to take away from Pelican, but I called Sunset Porsche up in Oregon and I got the pump for about $269, gasket for $7, and coolant for about $18 each. My prices may be 1-2 dollars off, but they are much cheaper than any dealer i've seen. Oh and no tax.

Thanks for the info i'll check into it.

When you get the pump out check the plastic vanes. If pieces are missing, pray they're not stuck in the small passages in the heads, creating hot spots and potential for cracking.

This is why I've proactively changed out my WP.

Thank you Clickman, i just ordered the parts that i need and should be here tomorrow.

Water pump/ thermostat
 

finished installing new water pump and thermostat, changed the belt, oil and flushed the coolant. everything went smooth everything is working great. ordered parts from pelican water pump $256 and thermostat $54. Thanks to Wayne Dempsey 101 projects for the Boxster, and to Pedro's Garage and thanks to everybody for the tips

OK, so I have a question..my car is a 2001 base...
I would like to add the center radiator, S oil inter cooler & low temp stat but can't do it all at once right now.
Would I gain much by just doing the stat & inter cooler right now and the center radiator once I get the parts for the rest pieced together?
I would flush the system & replace the coolant since I have no idea how old it is or if it's the right coolant (the stuff I have in there is green).
The car doesn't overheat or anything worrisome like that.

Sure, you don't have to do the center rad to get the benefits of the low temp t-stat and the larger S oil cooler. Do them in any order you like.

Bryan, I'm in the process of doing just what you have described. I've already replaced the water pump & hoses and have assembled all the center radiator parts (minus one bracket and the actual hoses & clamps). I plan to finish the upgrade itn eh fall when the temperatures drop. Right now the average day here is 100+ degrees. Too hot to work on the car for any length of time. :)

Take both stats and put them in H20 @ 186F measure the net area, forget about warm up duration its not that important what is important, are they the same net area for the same temp?

At 186F, the 160 stat is wide open, and has been for a while; the OEM stat has just the smallest sliver of an opening, if any at all.