So I get an error message on the first hot day of the year with me in the car...engine cooling fan potential failure. I go back and notice it is spinning fine, heat sensor is in place, coolant level is normal/correct, no cracks, but the air is now blowing up and out...pre-new harness it was blowing in "I think."

So I called my harness vendor. M.A. Shaw. Super guy. His harness is 50% of OEM and of the same quality. It is very, very high quality. Perhaps better than OEM. He happened to have gotten an email from me on this subject yesterday and had lunch with four Porsche mechanics and they all told him on the 996TT the air blows out.

So, I wanted to know if you guys could help me out and say if the decklid air fan blows in or out...probably best to check after a drive when it is idling...it is not very efficient so you can be fooled but a piece of paper over the vents makes it pretty obvious either way. Mr. Shaw suggested maybe Porsche changed things year to year. Hence the format of the poll is by year and in/out.

Needless to say, my error message went away with the new fan direction (I cut the harness, spliced, and heat tubed it last night). And the fan ran "less long" after driving... It could be another issue with my car, but this question comes up from time to time and I'd like this thread to be data for the rest of the board to use.

Just think of the fabspeed cold air kit...it says the "fan blows cold air directly at the filter".....but I want to be sure as he feels 4 mechanics are telling him the opposite. It makes little sense to me that you'd draw the air past the manifolds, turbos, and exhaust. But, I suppose this does let more water into the engine (not something Porsche seems to be worried about historically).

Here is a note copied out of renntech about a similar issue:



Group: Admin
Posts: 15,287
Joined: 18-June 03
From: Roseville, CA
Member No.: 1



There was a TSB on this for a few Carrera's with Aerokits. The purge air fan in the engine compartment had the wire polarity reversed on the plug connector. On the these cars the fan incorrectly blew hot air out. (The fix is relatively simple as you just reverse the pins on the fan plug.)

The correct function is for the fan to draw in cool air. You can test this (when the fan is running) by holding a sheet of paper between the spoiler and the engine compartment lid in the area of the ventilation slots. If the fan is functioning correctly, the sheet should be sucked on to the engine compartment lid.


--------------------
Loren
RennTech.org
PCA member since 1978


Thanks for your time and help everyone.


Jeff

 

60 looks and no clicks....some of you must know which way the fan goes in your car?

Anyway, no errors in my car with the fan going in....I tried to reverse it again and got errors again. Go figure....high heat here.

Jeff

 

I will have to test it. Going to rain here all week, so will probably be this weekend.

 

my fan failure light comes on very hot days when my car not moving but the fan still working i think its just comes on because it exceeds the reading on the temp sensor in the engine bay that is why the ecu thinks the fan its not working. it does go away after you turn the car off and let it cool down. i have an 01 with oem gt2 decklid and the fan is pulling the air out

 

Same, I get the fan failure light all the time on hot summer days when idling.

 

We've had 3 or 4 90+ deg days here and no issues. Of course, it's going back down to the 60's for the next week, but I'll try to check mine...

 

Thanks guys.

My errors went away with the fan blowing "in"... and to my brain, having cool air blowing down makes more sense. My only concern is H20.

Jeff

 

i will have to take notice next time i drive it

 

Next time I think of it, I'll test and post

 

Thanks guys. Early data suggest they may have switched polarity in 2002... just a hunch.

That would make your harness wiring year specific...just in case. Keep the data coming...statman will kill me.

 

mine pulls air into the engine compartment

 

The deck lid fan on all 996 Turbos pull air in to the engine compartment.

If yours is blowing air out the deck lid, it's not working as designed.

 

I'm gonna have to check mine. However when it's blowing in cold air, it's kindoff working against itself as hot air raises, on the other hand if it is extracting it is drawing hot air from under the car/exhaust into the compartment.

 

Porsche knew what they were doing when they designed the system.

You won't be too concerned about "hot air rising" when you park your car with the engine off and check how forceful the air is being blown out the bottom of the engine compartment when the fan turns on.

 

Just did the test with the Durametric drive link option "Purge fan" and it draw air into the engine compartment on my 2002 TT