simsgw

Thanks. She was a real sweetheart.

Do you really believe that Luddite nonsense? I could build a system (and we do in other contexts) that would hold temps to the nearest tenth degree at a single point of measurement. Gradients develop in the system as operating temps change, but that's normal. The stability of the Porsche system is no greater than the one in our NSX, and neither is as good as I could do in an industrial environment where greater precision really mattered.

As I say, the one in our NSX was just as stable as the Porsche's, but when the occasion arose that we had a problem it reported temperature fluctuations with half a second response time.

Not that true believers in this myth will care, but building a gauge to behave in the silly ways I've heard described would be considerably more trouble than using ordinary good engineering to make the coolant temperatures as stable as I observe mine one to be. All the reports of wider swings sound to me like legitimate cases of the coolant temp reflecting engine extremes of operation. I have no trouble at all believing that the coolant is providing the stable referent for subsystem design that you want in a system like this.

This is just ordinary high-quality performance. Why fake it? What are you people comparing your Porsche to? A 1949 Willis?

Gary

simsgw

Sorry, I meant to answer this and forgot it when quoting.

That is not what 'peak' means. Peak means what it means in ordinary English: a high point. The rapid rise and fall in reaching that altitude are a separate issue. If you're getting real spikes in coolant temperature on throttle application, your problem is not the gauge or the thermostat, it is something else. Possibly it isn't 'real' because you can have a problem with the sensor in the engine. If it is an actual sudden rise in measurable coolant temperature followed by a sudden drop, one cause I've seen is a failing head gasket. When the effective cylinder pressure gets high enough, some of the gases of combustion escape into the coolant passages. Those create bubbles of very hot fluid even if they are absorbed into the coolant liquid. Those bubbles of gas, contaminated coolant, or mixtures flow to the point where the coolant temp sensor is installed. As they pass over it, the temperature goes up and when the bubble passes, the temperature returns to normal coolant range.

This happens even when the engine is relatively cool so you can see it before the thermostat opens. I can't think of a reason you wouldn't continue to see it after the thermostat opens but that may be a deficiency of imagination on my part.

The important point is that coolant temperatures do not spike in a healthy engine. The mass of the coolant acts as a stabilizing influence so temperatures rise and fall in a smooth curve if you were recording the reports from that sensor. The only way they suddenly rise and suddenly fall is if parts of the coolant mass are markedly hotter or cooler than the rest. That is never a good sign.

If you have 'spikes' in your temp reports, have it looked in to, and hope it's just a sensor about to fail.

Gary

gpjli2

I appreciate your thinking Gary. If you read LN's treatise on the 996/997 engine and it's modes of failure they discuss a specific problem with these engines that involves a temperature spike under certain conditions of operation. It is probably beyond the scope of this post and I fear we have highjacked a really good post about adding radiators. Sorry OP.

simsgw

I haven't, but let me call attention to the critical phrase "modes of failure" and again suggest you not ignore any such symptom. Really. I narrowly averted buying a complete new engine when that happened to us.

Incidentally, they're all boxer engines, but it very nearly ends there. The engines in the 996 and the 997.1 and the 997.2 are cousins at best. All three have important differences and speaking of "the 996/997 engine" can lead to fallacies.

Sorry about the hijacking, radiator guys. Carry on and we'll tiptoe away.

Gary

ray09c2s

I was experiencing oil temps to 275 degrees at Mid Ohio road course recently (Jun NNJR-PCA) and the outside temps hadn't exceeded 85 degrees....purchased the car in the fall of 2009, and have run 7 events with no problems until then....have a friend with exact same car, except 6-speed, and he had added the 3rd radiator and oil temps were running no higher than 235 degrees. Just got back from Watkins Glen, and oil temp never exceeded 250, which had been the normal running temp on the track previously, so hopefully adding the 3rd radiator has helped me.....

MileHigh911

I think what we are seeing is that the PDk in "sport plus" auto mode runs the engine to it's max. I have an 09 C2S. When I track it, I see temps from 250-near275 when I have it in "sport plus" and let the car do all the fancy shifting. When I run it in "sport plus", but manually shift gears, I tend to upshift earlier than the computer, and my temps stay in the 220-235 ish range. My brother has an 11 C2, but a manual. He sees temps stay just above 200, and he runs his hard, but doesn't redline it every shift. After we analyzed our laps and track data, it was obvious to us, the auto mode in "sport plus" runs every shift to redline, and rarely lets it fall below 5000k. Notice though, Porsche does not put a "red warning" area on the oil temp gauge. When it was nearing 275, I was thinking "time for a cool down lap". I have no idea whether the car would "shut down into a limp mode", and I really don't want to find out. To think Porsche and it's brilliant engineers made the car perfect from the start is non-sense!!!! All Mfr make mistakes, and thus the future improvements that come along. The 3rd radiator to the 11 and newer PDK cars is very telling IMO.

ray09c2s

Obviously, Porsche didn't consider it a problem in our model years, but enhanced the newer versions. As an FYI, I have run twice at Mid Ohio, and in sport plus, I'm right at 250 degrees max.....one of my instructor friends has an '09 C2S 6-speed, also added a 3rd radiator, and never runs this high...
It was a good idea to run a cool down lap, as our service manager strongly advised against running over 250.

lopro

great install, clean writeup and pictures. thanks for the info

USMC_DS1

Thanks for the write up OP. I just ordered one from from Suncoast.

caddsource

Great write-up. Really appreciate sharing all the pics. I do track my car, no cooling issue, and one can not loose with the added safety on 100 plus days.

crazycarlitos

Its also a preventive measure against cylinder crack, according to Hartech

http://www.hartech.org/docs/buyers%2...20part%205.pdf

its over 70 pages.. so i'll copy/paste Dcreed10's summary

Porsche kept the same block for the 3.4, 3.6 and the 3.8 and every time they enlarged the displacement something had to give, and that something was the coolant passages. Then in order to save a buck they got rid of the old head gaskets which were side dependant and actually allowed for differing amounts of coolant flow for each indiviudal cylinder (some cylinders naturally run hotter than others and need to be cooled more) and replaced them with a generic one gasket fits both sides part which doesn't allow for differing amounts of coolant flow to different cyllinders. This causes some of the cylinders to run hotter than they should and it's usually these cylinders that have the problems. Hartech actually did a lot of their own research and found that the coolant flow to the cylinders is aprox. only around 5% and that most of the coolant gets directed to the head. The other problem is an inherint design flaw. The older 993 and back motors had the oil squirters on the top of the cylinders and this allowed for gravity to disperse the oil down too. The M96 and M97 motors have the oil squirters on the bottom and so oil doesn't get to where it's needed on the thrust side of the cylinder in some cylinders and this leads to cylinder liner scars due to overheating and bad lubrication. The temp gauges in the cars are set to read very conservatively too. They and LN Engineering have done their own tests and both showed the car gauges to read about 15 degrees cooler than actual.

These cars are like the old 2.7 liter cars, they need to be run cooler in order to survive. This doesn't apply to the Turbo or GT cars as they use a better engine with true dry sump systems and they run a lot cooler.

So if you have a M96 or M97 car, it's needs to be cooled better.
* Replace thermostat with 160 degree unit.
* Add Porsche 3rd radiator kit, Suncoast sell it for $250.00 direct bolt on.
* Use the best oil you can... (I'm actually in contact with a company that is making a Tungsten Disulphide nano-sphere oil additive which is proven to lower heat and reduce friction by about 50% and has a tribofilm property that will start to fill in cylinder scars, it's very trick stuff that the government and NASA has been using for years to lubricate the moving parts on sattelites that need to operate for a decade or so with no maintenance.)

f4 plt

did a third radiator install on my '09 C2S last Summer and glad I did temps have been warm down here to say the least and the coolant temp stays right at 175. Before install spirited driving in the Summer would raise it.

ray09c2s

f4 plt Don't ever trust your coolant temp guage...all the Porsche cars indicate 175 degrees, regardless of how hard you run....in my 09C2S, the third radiator was added for oil temps running over 250 degrees prior to installing.

f4 plt

I tend to agree with you as to all the gauges, however I actually did see a coolant temp above 220 before I added the third radiator, now I was pushing the car and the outside temp was over 100 ( and don't give me that dry heat BS... it was hot)

I do believe the third radiator helps but would also like a better oil cooler.

Insomnic

Great write-up; I just did this mod over the weekend with no issue. I was more excited about the mesh to be honest, as I'm constantly vacuuming out these ducts with a shop vac (had something furry in there the other day.)

As many have already stated, its at worst a warm and fuzzy for those in extremely hot areas and/or are tracking (or you've pulled off the bumper cover for another reason and said to yourself "why not?")