Cooling Fan air deflector

[sf911]

How important is the air deflector that bolts to the alternator ? I've had my 1984 Carrera for about 8 years and it wasn't there when I bought it . A fellow Porsche owner told me that it was terribly wrong not to have it and my engine will be ruined if I don't install one right away . My car has never overheated and runs strong . Is he being anal or should I start shopping for one ?

[Lyle O]

If it wasn't needed, they would not have put it there to begin with. Given that they saved grams of weight by using aluminum lug nuts and wooden floor boards, the weight save alone would have been worthwhile. There is certainly an aerodynamic function to the stator. Let an expert in air flow dynamics weigh in, though, to explain how.

[Tidybuoy]

My guess is that you '84 has been running fine without the deflector but not necessarily at optimum cooling. I'm no expert but I think the purpose of the deflector is to spread the air around to the various cylinders. Not having it probably won't cause immediate damage but might make the difference of an engine running 350,000 miles vs 300,000.

Myself being anal, I would replace it. I hate having missing parts.

[Discseven]

The clockwise rotation of the fan and its position above the engine means the directional flow of air leaving the fan is primarily focused on the 4-5-6 side of the engine. Were the fan mounted below the engine and rotating in the same direction, the 1-2-3 side would receive the greater volume of air. The air deflector serves its namesake by diverting air to more evenly distribute flow over all cylinders.

If you were interested in proving this, the plugs should reveal the temperature each cylinder is running at. So without a deflector, the plugs on the 1-2-3 side should show a hotter color to them compared to the 4-5-6 plugs.

[gazzerr]

Yes like Discseven said it was added for this purpose because of cooling problems on the 1-2-3 side of the engine. I would definitely find one and install it.

[sf911]

I think that i'll pick one up . BTW there is no difference in plug color from left to right .
Thanks , Scott .

[HarryD]

I had a damaged deflector in my car when I bought it. After a few years I d cured to get a proper replacement. While not 100% scientific, I did notice my car now runs a bit cooler I think it is needed. Go get one.