What is this part on the passenger side?

I took off my passenger side coolant hose on the top of the engine right above the engine mount and noticed this black thing that is plugged into the top. There is some kind of long hose of some kind attached to it. Looks like some kind of 45 degree elbow valve. Located just to the right of the electrical wire connector Any ideas what this? Just thinking it could be an easy replace while your are there item?

crankcase vent valve (check valve). it connects to the long gnarly AOS hose. real pain to get that retaining bolt started on my boxster. Not much to the part so I don't think it requires replacement.

Year, make and model please. The elbow looks like a breather. Could be part of the fuel and evap system but I'm not finding any part that looks like that on a 996.

#6 here http://www.autoatlanta.com/porsche-p...section=104-10 click on the part number for a picture of the crankcase breather

Yup, breather, hose goes to AOS as stated above. Easy to replace, the one on my 2000 had a leaky o-ring, so I swapped it out. I wouldn't replace it unless it is leaking or damaged.

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1999 C4 manual cab

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Cleaning or replacing it can extend life of the AOS.

Yeah that long hose looks very difficult to remove and reattach to the AOS.

The breather is attached by 1 bolt to the head. Remove it & pull up on it, making it easier to release the AOS hose by pinching the integral clamp. Check the o-ring for damage.

Ok sounds good. The hose replacement seems hard but the breather itself pretty simple.

You don�t need to detach the hose on the AOS side. It has a plastic clip so you can detach it on the Y vent end.

Thanks guys!

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Having some problem getting the hose detached from the plastic elbow vent. Got the 10mm bolt undone and the elbow is free. I've tried several things including squeezing the hose, squeezing at 6 and 12 o'clock and 9 and 3 o'clock. There are no gray colored clips showing where or how to squeeze. What am I doing wrong?

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Post a picture. I think I've seen at least two different versions.

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OK here is a pic. Disregard the white liquid paper mark which was just for reinstallation purposes.

You just squeeze the oval loop where it is wider, this makes it into more of a circle, releasing the catch, so you can pull it straight back off the barb. Press in at red arrows:

Thank you so much cds72911!

Whatever you do, don't damage that hose - you'll have to drop the engine and remove the entire intake plenum (and maybe some other stuff) in order to replace it... Don't ask me how I know...

OK guys. I tried pressing the two areas where the red arrows are and I still can't get this damn thing to come out. Do I need to pry this thing with a screwdriver or grab the vent with pliers and trying to forcefully pull it out or what? Maybe I need to pinch it just so that it is perfectly round? I can turn the vent around but it won't pull out. I don't want to damage the hose. Although the space is kinda limited, I can still get enough leverage on the elbow to pull it out but it won't budge.

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You would think with all the oil around that the o-ringed connection would be easy to pull apart, but it isn't. Usually takes a bit of prying with a screwdriver at the separation point to get it to break loose while squeezing the release.

Yes they can be tough...Just don't get crazy and break it!

I spent 2 hours on this damn thing and no success. Rather than break something I have left the vent alone as all it is is just a plastic part. I knew I should have left this thing alone but curiosity got the best of me. Anyway, I replaced the o-ring but now I can�t get that 10mm bolt back on. There are wires and AC hoses in the way so that you can�t get a straight shot to get the bolt started. Tried all kinds of extensions, u joints, small wrenches etc. there�s just no room. Anyone have a clever solution short of taking the compressor off? And second question. The vent now turns freely in the hose. I�m worried that this may not be good as it may leak air? Was kind of tight when I removed it from the block but after all that finagling it now spins within the hose I�m thinking maybe it was because it had been sealed and stuck on their so long? I don�t think the hose has any replaceable o-ring? i convinced myself that the 996 was such an easy car to work on but it�s not. Why the hell they made some of these bolts and connections so difficult is beyond me. This frickin bolt is ready to take the top spot for me in most difficult bolts ever to remove and get back on. I thought the fuel pressure regulator 10mm bolt on my 1990 Toyota Camry All Trac was difficult years ago but this one takes the cake.

Take a break, take the night off. That bolt isn't really that tricky, but fatigue, frustration, etc. are getting the best of you. Take some time off, get some rest, and try again tomorrow. The 996 is very easy to work on. German engineers have this stuff figured out.

^^This! Wait till you have an AOS replacement to do

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Yup I was thinking the same thing. Just need to clear my mind and make it simple. Today it was hotter than hell and mosquitos biting the hell out of me. Yeah I should have sprayed on some repellent but I was on a mission and couldn�t be bothered. Then combine all this with the stupid LED light that won�t stay in place and shine on the bolt. And then trying to hurry up before I have to meet my aunt for dinner. Lots of frustrating things going on at the same time make for a difficult bolt even more difficult. Yes i I still believe the 996 is deceptively easy and simple to work on. That�s why I love this car. Everything is fairly straightforward. It just takes a lot of methodical steps to get to the actual part you want to replace. Thanks for the positive words. Gives me inspiration when I tackle this bolt this weekend.

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I have already decided to do this. https://rennlist.com/forums/996-foru...l#post15806278 This stupid elbow vent to the AOS was supposed to be a simple appetizer and warm up. And now I�m starting to second guess myself.

Finally got the elbow vent off today. Took a big slip joint plier to push the hose together (there are 2 ribbed areas where the red arrow is) and after a little wriggling the thing came right off. I used the same technique yesterday but it would not work. Guess a day to rest and think it over really helped. I thought this was just another unnecessary plastic elbow so just for kicks I decided to test it. The vent part of the elbow (not attached to anything) does have some type of valve in it. On the new one if you suck on it you can barely get any air through it. On the old one, air moved fairly freely with a grinding kind of noise so I think the valve was on its way out. There was also a small thin puddle of oil in it so I'm glad I was able to change it with a new one and I'm thinking if oil is this far away from the AOS, the AOS may be at the point of needing replacement. Part number is 996-107-047-51-M100 and it does come with the o-ring. The o-ring itself is part number 999-707-154-40-M127. Just like in the post above, the easiest way to remove the valve is to get a 10mm socket on it with a long extension and swivel joint and it will come undone. After that, you will have more room to access the hose clip.

Now I am trying to get that 10mm bolt back in but all the AC lines and big coolant pipe are interfering. The thread on the block does not start until the bolt goes in a little bit but I can't get any leverage or torque on the bolt because there is no space. Meaning the bolt has to be completely straight to go down but with the swivel socket it will only go in at an angle. Anyone know how to remove that small black wire connector to the left of the bolt hole? There is another solid pipe of some kind behind the electrical connector that will not move so I need all the room I can get.

OK got the damn bolt threaded on finally and was so happy I decided to call it a day and tighten it down tomorrow. The rigid pipe that was in the way is actually connected to the AC compressor hose that runs straight up. Just pulling up on the hose will move this little pipe just enough so that you can get the 10mm socket on to the bolt and thread it in. Make sure to snake the extension and socket in between the tangle of hoses above to get a straighter angle. I used a 1/4 ratchet with a u-joint and a very long extension. You will have to press down on the bolt just enough while threading it in simultaneously and eventually it will get started. Still could not figure out how to get that electrical connector loose... Now on to the AOS.

If you thought that was a challenge, replacing the AOS with engine in the car is one of the most challenging PITA jobs I have ever done. I've wrenched on machines/cars/ships for 45 years, and this job requires every thing and then some. Read through other threads on AOS replacement. Read them carefully. A lot of good pointers from those that have done this. It will test every bit of patience you have. Your left hand and arm will take a month to heal.

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I�ve read as much as possible. The DIY on Renntech is pretty good and makes it look fairly easy. I�ve read that on the early cars are easier to replace. I am mostly worried about that hose connector at the bottom of the AOS. Did the water pump and have already removed the coolant expansion tank, fuel filter and every single coolant hose (except the radiator hoses) to replace so I thought might as well go all out with everything out of the way. Good thing I have another car to drive while I�m on this project so I�m able to go slow and do one thing at a time.

Does anyone go at the AOS from below? I've only done one AOS and it was with the engine out of the car, but it looks like there may be room to get it done going up beside the transmission.

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I�ve looked at the AOS from below. There are 3 items that need to be removed to allow the AOS to be pulled out from above. First you need to remove the 2 10mm bolts which are very easy and accessible. Undo those and then cut the bellow in half. Then undo the hose connector. I was able to get my hand in there when I was cleaning up the area for prepping. Looks like you can squeeze the connector with 2 fingers. This will be a challenge as there are several other peripheral wires and connectors attached nearby. And I�m dreading the fact that I had such a hard time with that stupid elbow vent connector hose that this may be just as difficult to get off. Once the AOS is lifted out and out of the way you will need to remove the remaining bottom part of the bellow that is clamped on with the Oetiker clamp which can be cut off easily with wire snippet/cutter granted you can fit one in there. Remove the rear tire to give you lots of extra room to maneuver. Sounds pretty simple but you never know. This is is my plan anyway. And having a lift would make things so much easier as opposed to being on your back.

Whoever says the 996 is easy to work on has never spent time around something like a V8 mustang. 996 requires massive dexterity, everything is working by feel, a litany of tools, and the requirement to remove tons of parts to get to anything. all the while stooped over to get under the stupid decklid.

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I agree totally. I was even thinking this morning damn my next car is going to be an American car. Easy to work on and none of this German methodical 100 step removal process just to remove simple parts. But there really is nothing better than a finely tuned and running 996. A fantastic car to drive!

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I just did an AOS. The biggest challenge was the farthest intake manifold bolt! I think a short box wrench with a 90*ish bend would help. The pinch clamp can be grabbed from underside but you have no leverage to pull it off the AOS, so I had to wait till the AOS was off the block before I could get it off. Lowering the motor was the only way on my .2 and I highly recommend anyone to just lower it and waist no time. Pm me if you get stuck and need help. It takes a lot of patience...

Bill, I have limited experience here, but from below the AOS on my .1 and my .2 look like completely different designs. Now, being used cars (and one engine being an AT from circa 2008) my .2 may not be original, so I don't have great data points.

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I too have a .2 with AT motor, so who really knows? Either way, it's a pain!

Dead thread resurrection. Is it required to remove the large coolant hose to get this vent out? I can't see another way to get enough access to release the AOS tube, and access the bolt. FWIW, I did this already on another 996, but I can't remember if I had the coolant hose off at the time. I don't want to make a mess if I don't have to.

I went ahead and removed that coolant hose. Everything on that end of the head is real hard to access. If you haven�t refreshed your coolant this would be a good chance to do that. Also replacing the sensor and just cleaning up the oily mess in that area is easier. I think PT3 sells a vent cap for that safety valve elbow as well.