What the hell is it
 

Could someone please tell me what this is. Im putting in my rebuilt motor and dont know what connects there or if i can just block it off or not. It is on the backside of the lim. Thanks

Isn't that a coolant line for the heater core? Also the infamous hose that always breaks becuase of the oil pedastal just above it?

If its inthe back of the LIM, it should be the connecting pipe to the air tube that feeds the cat or out to the air muffler

what year and is it on the engine or what I don't know what the LIM is sorry

Then why respond?

There should be nothing on the LIM. The only thing it could be is as posted split air pipe from the ACV.

What did you take off it?

Pipe for the auto trans????

Its not even part of the intake assembly.... When looking at drawings the heavy lines are whats being depicted. The faded lines 'could' be part of the engine, the firewall or some other part of the vehicle.

Looks to me like the Heater core hose. Coming out of the firewall.

Its an s5 engine with an s4 intake and by back side i meant the side facing the fire wall. i dont have any extra hoses to hook up to it so i dont know if the previous owner just took it off and kept it that way

The picture shows the PD on the front so its an n/a im assuming. Seems like its the metal line that comes off the LIM to the brake booster if i'm not mistaken. If you have one for the booster already I'd say just the others with the heater core coming out from the dash.

Jeez this thread is frustrating. I don’t have an NA so I'm not sure what it is but I can tell you that it is on the LIM (you can see it clearly in several FSM pictures) and it is not a heater hose (their connections are nowhere near the LIM). My guess would be brake booster, but surely someone with an NA can just go out to their car and look? How hard is that?

split air

I just tore one down to rebuild it the other day. The only thing I remember on the lim was the ACV same as turbo and the 6pt.

I assume the photo is showing the pipe from the ACV.

^^^ he speaks the truth

On the S4 N/A intake manifolds, the ACV dumps the air to the cat through the intake manifold at that nipple. That nipple comes out of the back of the LIM as shown and connects to a piece of rubber pipe, which connects to the catalytic convertor via a pipe with a check valve on the end.

Its not the brake booster line.
Its not the coolant line.

We know its an S4 N/A... look at the EGR valve located on the center iron.
Look at the ACV valve... Hose going into the ACV from the air pump, but no hose coming out of the ACV.

On the S4 turbo models, the air also travels through the LIM, but there is no nipple. In its place is a flange mounted pipe, mounted on the back edge of the runners. The EGR valve on the turbos is located where this pipe is shown.


Answer: Its the split air pipe which connects to the catalytic convertor on an S4 N/A only.

Your memory is failing you.
There are 3 different S4 ACV's.
The N/A manual trans, the N/A auto trans, and the turbo.

To go even further, the turbo ACV's have a different bolt pattern than the N/A ones.

They are completely different units.

You are right, though, that this is a pipe from the ACV... its just not connected to the ACV. Its connected to the LIM.

incase someone reads it, i know na and turbo acv are diff, im not stupid...

i was refering to... i said that was correct

ok thxbye

Actually that picture is from page F1-4 of the S5 FSM, which incorrectly shows the EGR valve (with no label). So either both S4 and S5 engines have the same split air nipple or it's another mistake. ;)

Great to see and answer finally! :)

looks like the ABS thing

Im asuming that this was responsible for supplying the actuators with the back pressure needed. But i dont have the auxilary system set up so is this just gonna create a vacuum leak if it is not pluged up

Or i could be completly wrong about what its for.... i just need to know whether or not its gonna create problems with starting up the engine

It WILL NOT create problems when starting up the car. I ran without it for a long while. It DOES create a vac leak, but it's only about 90-125 RPM worth of a vac leak.

Go to Advance Auto or NAPA, and look for a normally *very* small display of "HELP" brand products. Get the biggest cap they sell, called the "Bypass Cap" --- It is a perfect fit. Little bit of RTV on the nipple, cap on, and a clamp.

If you are not runing the stock 6pi and you do not have emissions or wanting to run the AWS system just remove and block off the ACV. Other words cap it.

After the thread is awnserd we get this useless post.

Bunch of dummiies. It's where you connect the brake booster feed. Different than a turbo feed tube. Noooooobies all.

Uhm... No.