This job is as dirty as a rag that's been used to clean the bathroom. Do it during daylight, since the hoses are black.
One of the things that tend to need to be done
on the 5 cylinder cars especially after 100,000 miles is a really good clean of all the
breather pipes for the crankcase ventilation system. After a while the pipes become
clogged with old hard oil deposits and condensation, forming a delightful mixture of oil
and water known as "mayonaise". This strangles the engine of it's abiltity to
scavenge the gasses out of the crankcase affecting running and in extreme cases
emisssions, the cure for this is to clean them all out with a good quality aerosol spray
carb cleaner, I prefer to use Wynns as it has a good powerful spray.
Before you do the breather hoses, it's usually advised to check out your cloth vacuum lines.
These supply vacuum to turn switches and make the world go round. Buy a few meters from Rod @
The Parts Connection (In Parts) and replace the vacuum hoses when you
have a chance. A little lubricant spray is advised to get these little buggers off.
To start with you need to remove the trunking above the airflow meter (above the air filter housing) completely and clean
the inside of that first (a good bundle of lint free rags is essential for this job), next
unclip the airflow meter as if you were replacing the airfilter and spray the top of cone
and wipe clean , do the underside of the plate also. The next pipe to do is the pipe that
runs from the back of the airbox to the top of the valve cover, this is held in place by a
hose clip at this end, take the cleaner and spray it into the pipe and watch the muck come
out the other end. This is one pipe that takes a lot of heat from the exhaust and
manifold so it is likely that it will be very soft and need replacing, the p/n for my
Coupe is 035 103 221 R. If you don't fancy paying the money that Audi wants for this part,
it is possible to use 3/4 inch heater hose and make one yourself along with a couple of
new hose clips to secure, the difference is about £17.00 gbp, enough said really.
The next pipes are the ones surrounding the Idle Stabilisation Valve (ISV)
(
pic 1, pic 2, pic 3), you will need
to disconnect and remove the ISV, then undo the hose clips attaching the
various pipes and clean thoroughly with the carb cleaner. There is also a pipe that
attaches itself to the cylinder head between the injectors this is also another good one
to look at. There is also a metal tube that runs from the valve cover (connects up near
the ISV) down the right hand side of the block that needs to be taken off and cleaned,
this is another classic one to get badly gunged up, you may need to soak this one for a
while or run some stiff wire through to help dislodge any muck in there.
Depending on how far you want to take it the dome that the the metal pipe runs to can be
removed by prying it off with a flat bladed screwdriver. Inside, you will find a recess
with lots of old oil and gunk in it. At the bottom there should be a drain hole into the sump,
chances are this will be blocked and need unblocking with some wire or drill.
Next comes the throttle body. This is removed by unscrewing the four allen head
bolts, removing the throttle cable and the multi plug on the side of the TB (note that you
may need a new TB to inlet manifold gasket, although I have reused mine with no problems).
Once it is off then you will carefully open the butterflies on the TB and clean with
a soft rag and cleaner, DO NOT take the TB apart, the only thing to remove is the idle
screw, try and remember how many turns it takes to get it out, this will help when you
come to reset the idle speed. It may help to put the TB in a vice ( light pressure only)
as it seems you need two pairs of hands for this job.
Once you have finished all this and reassembled it you may find that the car runs a bit
lean so maybe best to get the mixture checked and adjusted if necessary. I would ceratinly
clean these hoses every couple of years as some of the air passages are quite small
and clog easily
Notes: I completely ripped this off from Iain & Ralf's Coupe Quattro Homepage. The file has been changed to make it more "integrated" into
my site.
pic 1, 
pic 2, 
pic 3), you will need
to disconnect and remove the ISV, then undo the hose clips attaching the
various pipes and clean thoroughly with the carb cleaner. There is also a pipe that
attaches itself to the cylinder head between the injectors this is also another good one
to look at. There is also a metal tube that runs from the valve cover (connects up near
the ISV) down the right hand side of the block that needs to be taken off and cleaned,
this is another classic one to get badly gunged up, you may need to soak this one for a
while or run some stiff wire through to help dislodge any muck in there.