small hoses on rear of air filter box - 05 V70 NA Topic is solved

Post by **scot850** » 10 Aug 2026, 00:14

I was helping the owner of this car do a service on it as he is trying to learn how to do a stage 0 on the engine.

I have not worked on a P2 NSA before, so I have a question on the airbox.

There are 2 small pipes that come out the upper cover at the rear of the box lid between the air filter case and the fuse box in the engine bay.

I know that one is for the air flap vacuum that runs under the box to the front side and the vacuum flap controlling the air flap. However, the other one just has an elbow and nothing. I could not see anything obvious that is should connect to, but I was sure on the P80 NA it does have a 2nd pipe.

Can anyone tell me if there should be a 2nd pipe or if it just vents to air. Ideally a picture may help if possible. I know the 2 connectors are to the NLA air temp sensor for the air flap.

Thanks,

Neil.

Post by **scot850** » 10 Aug 2026, 21:19

No one have a P2 NA (might have to ne an 05-) that can see where these 2 hoses go? I have looked at the parts drawing and one goes to the air control flap on the airbox (it loops from the back under the airbox to the flap), but no idea abou the other one:

You can see the 2 hoses here:

https://www.volvocarstorontoparts.ca/a/ ... 78190.html

I don't understand this drawing as it tend to inply there are 2 pipes inside the unit and I don't believe there are, only on the outside.

You can see the hose here to the vacuum temp flap:

https://www.ebay.com/itm/326273156566

Neil.

Post by **scot850** » 11 Aug 2026, 12:34

Seeing as no help seems to be out there, I had a hunt again and found this video by Peppermint. He makes many Volvo videos and while he can sometimes be hard to understand, the sub-titles help greatly.

Anyway, at around 3m40s he shows the 2 pipes I have been trying to find:

It runs to the intake manifold from the LH (looking from the front) outlet vacuum outlet to the intake manifold RHS again looking from the front.

The vacuum controller is MLA that connects to these hoses on the airbox, so maybe this no longer works like is common on the P80 NA motors.

Neil.

Georgeandkira · Post by **Georgeandkira** » 16 Aug 2026, 12:36

Aug. 16th...first I've seen this thread.
Good for you helping your friend.
What I think happens is the the elbow on the vacuum supply hose -the one on the intake manifold- breaks and leaves the hose flopping about.
Replacing the elbow is expensive and I just used a short length of silicone hose -long enough to NOT kink- and sealed it with some high temperature cloth tape.