Oil drain plugs on 964

While changing my oil I noticed what looks like another drain plug forward of the primary crankcase plug. Its about 10 inches closer to the front of the car, just back from the clutch housing and tucked up near one of the exhaust manifolds. What is the purpose of this? Anybody?

That isn't the tranny drain plug is it? Is it a 10mm hex socket plug or a regular oil plug?

I take it you removed the underside panels? If so why? Do you keep them off or just took them off for service?

FWIW, I keep my engine pan in a large plastic bag against the wall in my garage. The car runs cooler and Bruce Anderson says it will keep excess heat off the exhaust valves.

I just changed by tranny fluid this weekend. I'm guessing you're seeing the tranny fill plug (or maybe the drain plug) as mentioned above. I've never noticed another plug that resembles the oil drain plug.

Good luck,
Mike 94 C2 cab

Many topics and opinions on this.

Factory says it improves aerodynamics, yet non of their factory race cars have them. They also help keep things a little quieter by not letting all that valve train noise out. I actually like the sound of a 911 air cooled engine and don't care about that extra noise dampening. The only nice feature I have found is that it serves as a nice, mobile, oil drip catcher to prevent that embarassing oil slick when leaving a friends house.

However, many (Bruce Anderson for one) argue that it holds in heat which can reduce the life span of the engine. For that reason alone, a lot of people remove them permanently.

Brian Smith
'91 C2

No, this is not the Hex-style tranny drain plug, which is much further forward. Its a regular nut style, about 15mm. Its right next to where one of the oil lines from the oil tank connects to the crankcase. It faces downward, unlike the oil drain plug which is horizontal. Anyone?

Oh, and yes, I permanently removed the sound tray but I do agree that it is a nice drip catcher when left on.

If I'm not mistaken, the pan underneath the engine serves two purposes:

1. Quiet down noise to some Euro Spec noise level.

2. Add additional aerodynamic performance at AutoBahn speeds.

I've recently finished an e-mail session with someone from Switzerland, and he indicated that some of the diagnostics related to emissions weren't available on Euro units. Odd isn't it....they worry about noise pollution but not air quality!?!?!

When I finally get under my C4, the pan will be a nice addition to the storage areas in my basement!

Was crawling around under mine last night (car, that is), and noticed a drain plug toward the rear of the engine on the drivers side facing the primary muffler (bypass in my case). It's a round plug with about an 8mm hex head (allen). I know this is not the one referred to earlier in this post, but. . .any ideas?

that's the oil pressure relief valve sealing cap. no reason to remove it.

Does anyone have the under-engine cover that they wish to sell????

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Bob
1990 Porsche C4

> 1. Quiet down noise to some Euro Spec noise level.

Well the swiss people live beetween big hills and have lots of echos. To much noise can loose avalanches in winter. You donīt like to sit in a car when the hill comes down. Also streets in europen citys are narrower and people do live in the groundfloor too. Even the suburb structure isnīt comparable to the US.

> 2. Add additional aerodynamic performance at AutoBahn speeds.

Thats correct, inded it prevents the wind geting catched under the chassis and adds some downforce. It will also help venting the cooling air exhaust just by using the venturi effect. Racers remove them as they go go abouve the curbs sliding on the floorpan and the heatshield will get destroid or wil fly away.
This effect is only noticable ad very high speeds.
And the 964 is not a wing car.
New Porsches 996 donīt have it too so it must be useless.

>I've recently finished an e-mail session >with someone from Switzerland, and he >indicated that some of the diagnostics >related to emissions weren't available on >Euro units. Odd isn't it....they worry >about noise pollution but not air >quality!?!?!

Noise, is air pollution americans donīt seem to care about ?

About air quality just ask him about swiss MFK.

In germany you have to make a "Abgasuntersuchung" every two years.
I think the california laws must be very close to that. If you know germans you know it is worser then there.

Also in germany most race clases must be equiped with an catalic converter and if the converter is blown away you get disqualified.

Like in the staates some countries are more laid back about this issues. Swiss, Sweden, Germany, Austria make the pace.

Porsches are made to master all countrys. The US sticks to cafe & OBD II while we have D4. You have Trucks to have fun while here trucks, Vans and SUV have the same rules like cars. Europa also has the goal to lower total emison by more economyc cars. Something no one in the staates even think about. Well wy have prices around 3-6 $/Gal in europa. Loaded by taxes.

If the oil prices go high again Bush will jump in or even starts a new war ? Yesterday he quitet all those bad things that industrie doesnīt like.

Grüsse