The disparity is that in the engine there are areas that will have higher localized temperatures. It would appear they read the temperature somewhere that is more stable and the OBD2 provides a temperature that more easily deviates from the baseline. I've seen the OBD2 read 240F when the dash said only 215F when I had a HUGE airlock in the cooling system impeding cooling).

Get rid of that EVO intake since your intake air is 141 degrees.....

New owner, needs a little advice
 

Hi, noticed this thread and thought you'd be able to help. I picked up my 2004 Boxster s this week and haven't stopped grinning. However this week has been unseasonably hot in the UK and I've noticed the temp. needle move more than I'd think was normal.

My question relates to the rad fans, do they come on together? or sequentially?

If sequential which one comes on first, I noticed below that you say the passenger one comes on first. My car is RHD so assume the drivers side one should come on first.

I've not noticed the left rad fan working on my car and was wondering if this may be why the needle moves more than expected. Could I simply crosswire the fuses for a while to see left hand fan spins up.

Thanks in advance for any help you can provide.

Phil

start the car, and turn on the AC. Both fans should start up. more or less together.
Now, turn off the ac and drive, the fans should both turn on at 210-215ish. Mine turn on at 214-215. They both start more or less the same time. The fans are known to go out, so if the AC or high temp does not turn them on, replace.
If you have not done it, take off bumper and mobilize the first radiators. You will be amazed what is in between the two radiators. Buy redline water wetter. 5$ it can only help.
if all seems normal, look to the thermostat or water pump. Pumps seems to go slowly them BAM, overheat.
if you are going to replace the thermostat, might as well get the low temp one from flat6inovations. and if you are going that far, take off the pump and look at the cheap impeller, spin the bearings, replace it if concerned.
And if you are going through all of that, might as well change the fluid. Texaco extended or OEM fluid are great.

How hot does it get?

Has anyone replaced the low speed fan resistors with radioshack ones? If so I would love to have the specs or part #. Resistors are $80 from Porsche and I need both a piece and I need both. Just replaced water pump, flushed coolant system, replaced radiator cap, hoses, cleaned radiators,etc.
and that's just the cooling system.

The fans on my '97 2.5 turn on at precisely 108 degrees C which is 226 degrees F. Pretty hot, but I believe this is correct, at least for my particular model.

I spent 10 days in Italy last summer. Every day was over 40 degrees C (= 104 F) and the car never went above 109 C (ie just one degree higher than the fan cut-in temp). Think I'd probably rather see the fan cut in around 105 C.

These temps are all via the digi display, not the temp gauge.