Got it - thx Petz.

 

Bit of a dummy Q but can anyone with an M97 NA car give me your oil temp readings with 0w50 doing like around town driving? I just popped the center rad in, and I’m going from memory but it looks like my temps are a little higher than they were prior to installing the radiator. Ballpark 210-220. The coolant gauge stays steady at 175 but as others have mentioned in the thread it’s not known to be a super accurate reading.

 

Why would you run a third radiator for non-track use, based on what's written in the opening post?

 

Radiators work really well when you're in motion. Certain parts of US see temps north of 100F along with very high humidity. Sitting in traffic can really raise the oil temps and drop the oil pressure a bit. I've seen it in my car. This did not happen anymore once I added the extra cooling capacity. So yes, 3rd radiator can be an overkill but it's not a blanket statement that applies to everyone.

 

I'm no weather man, but the person who asked the question seems to live in NJ, so that looks like a different scenario.

 

First, I have nothing but the utmost respect for Baz. The following is just a data point for anyone reading this with a 9A1 motor ...

Mine is a 2010 C4S PDK that just went past 156K on a 600+ mile drive yesterday returning from Death Valley.

Pre third radiator I could see oil temps get as high as 275F. This was driving mountain passes in the Sierra in 100F plus ambient temperatures combined with thin mile high air. Low gears, high loads, relatively low speeds.

Yesterday we got a fairly good run across the 58 (just west of the 5) that load wise was near to equivalent to the Sierra drives. Oil temps were 225F and recovery back to 200F was fast. I was very happy with what I'm sure was a lower oil temp than I would have seen without the extra cooling. But put emphasis on the "near to equivalent" modifier.

In 2011 Porsche opted to put the third radiator into all PDK equipped cars. This is pretty specific and does not apply to any .1 or non PDK cars. So take the above for what it's worth. But there can be a reason for adding the radiator.

Note: I have not seen lower or higher than expected oil temperatures in normal everyday driving since installing the third radiator. Again, 9A1 motor.

 

do you have LTT as well?

i was always planning planning on doing BOTH the LTT + 3rd rad when the water pump gets changed.

no track use, .1 manual, summer driving only.

 

I do. I upgraded to LTT when doing my water pump and installed the 3rd radiator down the road. I also have a deep sump so I hold 10qts of oil which definitely helps control oil temps. Just this weekend I went on a little country back roads ripper and was able to do a bunch of full throttle accelerations to the red line. The oil just about touched 220F and dropped quickly after.

 

thank you - which car is yours? 997.1? manual/tip?

 

2004 996.2 with M96 3.6L + X51 engine. 40AE car.

 

Do we know the temp the OEM thermostat opens at?

Edit: Per an almost exactly 1 year old post from @Petza914 , I'll paraphrase:

LTT: Opens at 165º, open entirely at around 185º.
OEM Thermostat: opens at 180º and is fully open at around 200º

 

Correct

 

How much coolant is lost during the WP/t-stat replacement? I ordered the FR50 and will do the t-stat at the same time.

 

I would change out as much fluid as you can. I don't believe in lifetime fluids.

Peace
Bruce in Philly (now Atlanta)

 

A couple gallons. Everything in the reservoir and much of what's in the engine.