I'm still pulling together the photos to document the radiator install. But in the interim, I thought I would share a DIY tip that is widely applicable to anyone who does basic maintenance on their watercooled P-car. It stems from the radiator install. Since I was saving money by doing the work myself (with my 19 year old son actually), I splurged on purchasing an Airlift radiator purge kit tool.
The background is that the Porsche coolant system is long, with lots of turns and corners. It is very difficult to fill or top off the system and ensure that there are no air pockets left that will significantly impact the efficiency of the system.
The Airlift works by extracting air (as well as some coolant) and lowers the pressure in the cooling system to about -25 in/lbs of pressure. This is done by placing the tool in place of the coolant cap, sealing it tightly and hooking it up to an air compressor. Via venturi effect the system is evacuated. It's quite remarkable watching the rubber hoses collapse from the negative pressure. Then, closing off the system maintaining negative pressure, the venturi hose is disconnected and a second hose that connects the tool to a bucket of coolant is reconnected. When the valve on the unit is opened, the coolant is sucked from the bucket in to the car, filling every last corner of the cooling system. The system is completely filled when the pressure gauge rises to zero in/lbs.
It is actually quite remarkable. After installing the radiator and using the typical fill-drive-top_off-repeat technique, I thought I'd gotten all the air out of the system. But after using the Airlift, it sucked in an additional (approximate) quart of coolant. Plus, you really feel like Bill Nye the Science Guy.
Credit goes to the head of Discovery Automotive who uses it on all of the cars he services. He services my Ford GT (I don't wrench that car) and gave me the info when I asked him for tips on doing this radiator job.
If anyone is interested in more detailed step-by-step instructions, I'll post them.

 

why would you want to run the engine cooler than designed?

if its meant to run 200* warm, there is no use in running it 185 ect.. unless you plan to drive it like you stole it every minute you're behind the wheel.

i did a fan and thermostat mod on a previous vette. car was running about 15* cooler than normal and this was a street car. that 15* prohibited the engine from keeping itself running clean. when we tore it apart, there were all kinds of gunk and deposites.

if you have a specific need to add additional cooling let us know but to do it for the "cool" factor is a mistake imo.

 

May I use this third radiator with me 997.2 PDK ???

 

Unless I missed it, he didn't change his thermostat, just added a 3rd radiator.Your not going to see a drop in operating temp unless you change your thermostat, but you will see a drop in your oil temp with the 3rd radiator installed. We did the 3rd radiator in a buddies car, and the oil temp drop was the only difference we saw. I think the oil temp dropped about 25 degrees during traffic stop and go, and roughly the same when he was beating on it at the track. I will be doing mine this winter when I pull the nose for grills and a repaint of the bumper.

 

your oil temp IS your operating temp

 

It doesn't lower the operating temperature below the target defined by the thermostat. It just provides thermal headroom.

 

I disagree. If your oil temp gauge says you oil is 250 degree's, and the water temp gauge says 175 degree's, is your water temp gauge lying to you and your car engine is at 250 degrees operating temp? No, you would warp every piece of aluminum on your engine. They're 2 seperate systems. Oil temp does play a factor to a degree(no pun intended), but the cooling system as a system keeps the engine operating at the correct parameters.

 

+1..

 

Thank you.
Oh and re the discussion about operating temperature, isn't the answer subject to the definition of the term? That is, I believe that operating temperature is specified as the target value of the item you are measuring.
So in our cars, there is an operating temperature for oil, and an operating temp for water. Neither are actual measures of the temperature of various engine components. They may be, but it would be coincidental. Rather, they are proxies for the ideal operating temperature of key engine components.

 

The opening temperature of the thermostat in the 996 and 997 has no effect on the operating temperature (oil and water). Using a thermostat that opens at a lower temperature will only slightly increase the time it takes to reach the targeted fluid temperature of 194F. The weaknesses of the Porsche cooling system is both air flow and coolant flow, which can be easily corrected without adding a 3rd radiator.

 

So for those of us seeing high oil temps at the track, how would you recommend "easily correcting"? I am seeing 260 degree oil temps on hot days when sessions are longer (30-45 minutes) in my 997S and 3rd radiator has been recommended. If you have better, easier solution I would be very interested.