elbeee964

I have a grommet hole in my engine's cooling cover, about 1" in dia, that's w/o a grommet/plug. (So I guess engine cooling air is needlessly blowing out there.)
It's just a hole sitting there inboard of intake #4 & #5 (passenger side, intakes closest to bumper) in the cooling cover.

Anyone have the PET for that hole's grommet/plug p/n?
Or a PET picture to post that I could further ID?

elbeee964

Found it. Hope this helps the next lister:

Two grommets (one nests inside the other?)
Two places on the engine cover where the pair are installed. One where I said, the other inboard of intake runners #2 & #3.

911.612.328.00 ("rubber sleeve", the little 'nested' one, about $5)
911.612.327.00 ("rubber sleeve", the bigger one, about $5)

If you know differently, give a shout. Thanks.

Chipster

Lonnie,

I last night discovered a sizable hole in my air duct (#5) and was thinking "maybe some one will have a picture with a part # on rennlist" - and viola'! There it is

Thanks for the post!

BTW I hope the wheels are working out well for you.

Chip

Fred's 964

If it's the ones I'm picturing, the knock sensor lead goes through the smaller grommet.

Fred's 964

Here is another angle. I'll look tomorrow to see what went in that hole by the #5 intake. For those eagle eye detail oriented Rennlisters, yes I plugged the intake ports so I wouldn't drop anything down the intakes. BTDT.

springer3

Look also in the sheet metal at the rear of the engine. There are cut-outs for socket wrench access. Most 964s I look at have missing filler plugs at those locations. I guess the mechanics decided they were not needed after removing the access plugs. Unfortunately, scalding hot air off the exhaust enters the engine compartment if the plugs are missing. Sorry, I don't have the part #.

Fred's 964

Plugs below the motor mounts in the rear pan are #964.106.237.01

elbeee964

Hi, Chip. Great to hear from you. Wheels survived VIR with flying colors. Had sticky rubber on 'em and over 130. They'll do.

Fred-
Perfect pics. You nailed it. It's the little hole next to #5.
(Your engine is a 'runway model'! Stunning. My two pics are of my 'girl next door'.)
If anyone knows what the mystery hole is, shout out!

The mystery hole -



And an overview showing the knock sensor grommet/sleeve/passthrough. (Yeah -- looks like the pressure xsducer seal needs replacing per Garrett's DIY.)

Rocket Rob

Lonnie,

My cars have the same mystery hole. Not sure what its purpose is. I'm curious to learn the answer too.

elbeee964

Would really like hearing if your car sports this (unplugged) cooling cover hole.

Possible hole explanations -- Perhaps it's:
1) a pressure-dumping measure for the right bank only, sized to equalize cooling/temperatures differences between the left and right banks? (the right bank is a little closer to the fan than the left, so the right would get cooled more without this.)

2) an upper engine bay cooling measure... venting air strategically at some (otherwise) too-toasty topside piece?

3) an original design goof that wasn't worth fixing (as most of the engine cooling is handled by the oil, anyway?). "No harm, no foul".

4) a common production line (or maintenance shop) goof?

or...

5) ?

Fred's 964

Lonnie, I just checked, mine is open too. I had not noticed it when I re-assembled it. No spare parts left over, so it must have been open before I disassembled. I have no explanation, but am curious now. I'll keep looking for an answer. BTW, mine is a '91 C2 Cab.

I just checked the disassembly pix, the hole was definately originally open. As far as I know, the cover had never been off the engine since new.

elbeee964

Thanks. I'm increasingly relieved.
Still... This is quite weird.

(and it's becoming a subtle Porsche trivia gem in my mind -- why'd Porsche purposely dump air, here?)

wsybert

Nothing in mine either... The picture is right after I pulled the engine this past winter.

jimq

Fred
Mine has an empty hole also so its not a TIP thing.
I got my helmet at APEX a Rennlist sponsor. Good discount and lots of cool freebees came with it.

HiWind

Ha - found it - the mystery hole thread - thanks guys!