Engine bay query

[DaveA3]

Hi Peeps

I'm looking for some help regarding a few pipes. Long story short i had some boost leaks and put some silicon tubing in as a temporary measure so i could drive the car.

I wanna get some stronger ones from forge or anyone else or even dealer possibly. The silicon ive used isnt very strong and is quite flexible and im worried its sticking together with high vacuum. plus one of the smaller pipes is loose as the original had a reducer on the inside to help keep it tight.

#1 This pipe had cracked and split all over the place it was half rubber and half metal and worked its way around the side under the plastic bit. This pipe is loose on the bronze nipple part at the front of the manifold. Need a solution to stop any leaks. The original had an extra sleeve to hold it all tight. but again it was split.

#2 these pipes came in 2 parts one either side of that mystery valve. any ideas on what they are called and a suitable replacement? forge or oem? any info would be helpful

#3 what is that valve called and can it leak? r-tech mentioned i had a valve which was leaking he said its common for them to leak on these engines. dunno if its this one or the one in the PCV system underneath (if thats where it is)

please excuse my ignorance and my messy engine bay.

cheers! :icon_thumright:

Dave

 

[Imteyaz]

Looks like the hose (in blue) has replaced the original vacuum pipe used by the brake servo. The original part would have been a long twisty rigid plastic pipe with a short rubber hose connecting the nipple on the inlet manifold and the one-way valve sat between the two. The valve used is a one way valve so it only allows for vacuum, shutting off when the inlet manifold is pressurised under boost conditions. New original pipes cost mucho wonga I'm led to believe and as far as I know, the one way vlaves cannot be purchased separately.

It look like you have an AGU (Not DBW) engine so I'm not 100% sure but I'm sure someone will correct me if I'm wrong.

 

[beachbuggy]

#1 is a vaccum line that goes from the manifold to the Diverter valve. You can use any good quality 3mm vaccum tubing for this. Nothing special, but I personal wouldn't drive the car too hard with out fixing this. Without it working the Diverter valve doesn't function and if you have a mapped car and increased boost you can end up breaking the turbo.

#2 is a NRV or non return valve, Attached to the cylinder head to allow ventilation when there is more pressure in the head than manifold but when the car is under boost the valve wont let the pressure through.

#3 I guess it's just larger vaccum hose, I'd say 7 to 8mm. Again I don't know if FOrge or someone do a special kit but it is probably something you can just buy.

 

[DaveA3]

ok cool so theyll be ok for the moment then? just get them all clipped up tight n all is good?

 

[Alex C]

#1 Vac line to DV valve, looks like N249 bypas.. at least i can't see it, but might be somewhere else on the A3

#2 is the vac line for the brake servo

#3 is a one way check valve, you want a vacuum line to your brake servo, not a boost line

 

[DaveA3]

what defines a vacuum line over a boost line other than diameter? would it be stiffer than the boost line?

 

[Alex C]

no no, thats what the check valve is there for, it means only vacuum can be transmitted, not boost. When the manifold is under boost the one way check valve isolates the brake servo from the boost. When the manifold is in vacum, the check valve will open and the brake servo will `feel` the vacuum

i dont think there is a difference in type of hose, if you swapped the check valve the other way round then it would be a boost line not a vac line

 

[DaveA3]

oh i see thats for that mate! misunderstood. i just need to find something to get it tighter on the nipple on the manifold then im set!

cheers lads

 

[DaveA3]

lads if that check valve (#3) is faulty will it make the braking spongy?

Anyone have one of those engine diagrams with all the part numbers?

I think its this but need to double check. ACF 058 905 291 K

 

[Alex C]

no it will make it hard i think. The vacuum in the brake servo helps you depress the brake pedal. If there is no vacuum then it will be stiffer