What are the 2 quick connect hoses from the AOS lead to?

[Stiles13]

I am replacing the AOS in my 2001 Boxter and the bottom flex tube cracked in the elbow. It see it running across the intake but can't see the other end. Just got the car a week ago, and it the hose already had electrical tape around it.

[dlud]

That hose snakes under both intake manifolds and plugs into a fitting on the left side (drivers) of the engine near the front. It is really hard to see. If you take off the engine cover behind the seats you will see it under the a/c compressor. The photo shows the other end tagged with a postit note.

[Stiles13]

Originally Posted by dlud

That hose snakes under both intake manifolds and plugs into a fitting on the left side (drivers) of the engine near the front. It is really hard to see. If you take off the engine cover behind the seats you will see it under the a/c compressor. The photo shows the other end tagged with a postit note.

Yikes! Does it have stays holding it in? I ordered the replacement, but not sure what I'll have to remove to access it. is it a vent hose? What is it's purpose?

[dlud]

The connectors release by squeezing them. Once you receive the new hose you will see how they work. I know some who have broken the connector at the AOS have opted to cut off the hose somewhere near the AOS and splice in a section of hose and connector rather than replace the entire hose.

[Stiles13]

Yes I am familiar with the connectors, just wondering if there is anything attaching it in place. It is broken at the connector elbow at the AOS as well as the flex pipe where it attaches to the hard tubing under the manifold. Not sure if I can splice it.

[Quadcammer]

It goes to a positive crankcase pressure relief checkvalve

[Stiles13]

Originally Posted by Quadcammer

It goes to a positive crankcase pressure relief checkvalve

So, does it release pressure into the AOS? I'm assuming the pressure is low since it is a fairly delicate plastic hose?

[Quadcammer]

Originally Posted by Stiles13

So, does it release pressure into the AOS? I'm assuming the pressure is low since it is a fairly delicate plastic hose?

I believe the hoses will be subject to either vacuum or pressure, depending on situation.

Under throttle if you have some blowby, you will pressurize these tubes. The vent valve this therefore intended to vent that. Typically though, the hoses should be under vac.

[Brian in Tucson]

You should replace both hoses, they get brittle with age. And trying to splice them is the half as-sed way to go. Do it right or go home.

You will need to take the plenum cross overs off to get to the hose that goes to the left side. The crossovers are pretty easy to remove, you will need to remove the snorkel and some other stuff off to get the rear crossover out.

Get at least two cans of brake clean and clean out the crossovers, they will be oily. And a can of carb cleaner for the throttle body. Nothing seriously difficult if you don't break things as you take them apart. I have a vacuum diagram if you need one. (a really clear one.) I would budget a day for start to finish, tho it can be done in a lot less.

[Stiles13]

Brian, do you know which way to disconnect the end that goes to the front? I can't fit my hand through from behind the seat, and the air filter housing blocks the other direction. Any tips would be greatly appreciated.

[Stiles13]

Originally Posted by Brian in Tucson

You should replace both hoses, they get brittle with age. And trying to splice them is the half as-sed way to go. Do it right or go home.

You will need to take the plenum cross overs off to get to the hose that goes to the left side. The crossovers are pretty easy to remove, you will need to remove the snorkel and some other stuff off to get the rear crossover out.

Get at least two cans of brake clean and clean out the crossovers, they will be oily. And a can of carb cleaner for the throttle body. Nothing seriously difficult if you don't break things as you take them apart. I have a vacuum diagram if you need one. (a really clear one.) I would budget a day for start to finish, tho it can be done in a lot less.

Can you please share the vacuum diagram?

[dlud]

The rigid part of the hose is pretty tough stuff. Not sure if it is held in by any attachment under the manifolds. I'm also not sure whether there is pressure vs vacuum in the hose. I thought vacuum but not 100% sure.