[V6-12v] Removing Bolts and Injectors

Fri Sep 22 22:21:25 EDT 2006

great write up James

I have been woried about getting the cats of the exhaust manifolds as I need 
new cats. It looks impossible to get to . It looks like three studs coming 
from the exhaust manifold that go through the cat flange and 3 nuts go on . 
Is this the case and how did you get them off, did you think that one of the 
studs could break >?

----- Original Message ----- 
From: "James Whitehouse" <james_whitehouse1 at yahoo.co.uk>
To: "'Joe - Audi'" <audi at olderie.com>
Cc: <v6-12v at audifans.com>
Sent: Friday, September 22, 2006 12:39 PM
Subject: Re: [V6-12v] Removing Bolts and Injectors

Joe,

The vice grips in combination with the hex key did the job, thanks!

Here are my impressions so far, and a list of things that have been
problematic. I've copied in the mailing list in case this is useful to
anyone else in the future.

First of all, I need to clarify that we're doing a more major overhaul than
just the head gasket replacements. It needed a new clutch too, so the
decision was made to take out the engine, which means stripping down a
little more.

Overall, don't attempt it without the manual. It would be a nightmare. At
the very least make sure you have all the torque settings to hand. Don't
attempt anything that involves taking off the timing belt unless you have
access to the special tools 3243 and 3242 (cam locator and crank pin
respectively):

http://www.big-auto.com/wbstore/main.asp?action=PROD&PROD=VW3243AND3242&CTMP
=1

Firstly, there are a whole mess of wires and vacuum tubes surrounding and
attaching to different parts of the top end. I'd label these so you know
where to put them back. Some of the plugs are colour coded on the baulkhead,
but aren't obvious at the component end. The vacuum hoses aren't necessarily
marked.

Secondly, have some little food bags and a permanent marker pen to write on
them. There are a lot of little bolts, nuts, etc. of different sizes and you
could very easily get very confused!

Have replacement parts for things like exhaust manifold nuts, exhaust
manifold-to-cat nuts, etc. ready as well as the obvious gaskets etc. Some of
those parts are dealer only and some are so seized on that you're always
going to strip one or two getting in there. Putting new ones on also means
this is less likely to happen in future.

Some of the intake manifold-to-cylinder head bolts are a pain in the a** to
get to, as are the valve cover bolts. Make sure you have the right tools. A
long 5 and 6 mm hex socket is very useful, particularly with a ball end for
these. While the intake manifold is off, it's silly not to replace the
intake manifold gaskets, particularly the one that is sandwiched in the
intake manifold loop itself, as this cannot be changed with the manifold on
the car, and every time you take the manifold off you have to re-tighten the
head bolts. To change this you'll have to remove the injectors, so also have
6 injector seals (they should come in your head gasket set, Reinz ones are
very good).

Likewise, it's wise to replace the 'oil retention valves' which sit under
the little oval cover in the valley of the top of the V. Since otherwise you
have to take it all apart again if these ever give trouble. Absolutely
replace the gasket under this cover in any case, as it's a £2 part and is
renowned for blowing and you do not want to take the intake off just to get
at that, believe me. I replaced mine about a year and a half ago and I'm
doing it again now because I'd be mental not to.

Make sure you have ways of dealing with de-threaded nuts, etc. or a friend
with more experience in case you get stuck. I was lucky that I had a very
experienced mechanic around (although on the first day he was ill so I did
most of the strip-down myself). This brings me to another point. Having a
fully equipped workshop, with a car lift has been tremendously helpful. I
would almost say that I wouldn't like to attempt this job without one. It
could certainly be done, but I would leave much longer than normal to do the
job unless you're very proficient or used to working in this way.

Also very useful is a compressed air line. Among other things this is useful
for making sure the cylinder bolt holes are free of oil and coolant. Unless
you clean out those holes properly, you're looking for trouble as any liquid
down there can get compressed when putting the new cylinder head bolts back
in and cause hydraulic bottoming out of the head bolts. This firstly means
they won't tighten fully, and at worse can crack the block under pressure.

This brings us on to another subject, which is oiling the cylinder head
bolts. They do require a light oiling. This doesn't affect tightening
torques as the bolts are angle tightened at the last stage. A light oiling
means spraying a bit of oil onto the bolt while held in a rag, then wiping
the oily rag around the bolt threads. It is important that there is no
excess/ dripping amounts of oil as this can have the same effect as not
cleaning out the bolt holes (see above).

For more info on this, and general cylinder head gasket issues, see:

www.reinz.de/pictures/praxisinfo_3_eng.pdf

www.reinz.de/pictures/praxisinfo_2_eng.pdf

Make sure you have a way of cleaning off the carbon and other crap from the
mating surfaces before applying the new gasket. My heads are being skimmed a
fraction just to make sure, but I'm in a shop where they have the equipment
and expertise to do this in-house.

You may want to have a couple of the little locator pins (like little hollow
dowels (about 6mm x 22mm) that sit on the upper block and 'locate' the head
gaskets, essentially holding them in place while you lower the head onto the
gasket. They can either stay on the block, or in the heads, or shear off.
The Audi dealer will likely have no idea what you're talking about and try
to tell you they 'only come with the block'. But they do exist. I'll try to
post a part number if someone reminds me. Since they are 30 pence each, it's
better to have new ones in case, rather than having to wait for them to
arrive if they break.

The only solution I haven't found a problem to yet, is getting the coolant
out of the block since mine is gunged up down by the bottom drain plug.
We're hoping this will be easier once the engine is out. If anyone thinks of
anything or any way they know to get at this from inside the block, please
let me know!

That's about as far as I've got so far. I'll update and post a few pics at
some point.

Cheers,
James

> -----Original Message-----
> From: Joe - Audi [mailto:audi at olderie.com]
> Sent: 21 September 2006 00:26
> To: James Whitehouse
> Subject: Re: [V6-12v] Removing Bolts and Injectors
>
>
> On Sep 20, 2006, at 5:53 PM, James Whitehouse wrote:
>
> > Guys,
> >
> > I'm halfway into the head gasket stripdown. Two problems:
> >
> > Firstly, some monkey before me has rounded out the interior hex of
> > the valve
> > cover bolts (two of them). Any tips for removing these short of
> > drilling
> > them out? I'm thinking a reverse tap of some kind?
>
> Vice-grips have saved me in similar situations before with those
> types of bolts.  Of course, you may not have enough room in there to
> get a pair clamped on...
>
> -Joe
>
> P.S.  I've been anxiously following your thread to hear the results.
> I need to do the same work on my '94 100 w/ 175k miles but have never
> performed that type of engine work before.  Not sure if I'm up for
> the task.  Please let us know how long it takes and what other major
> issues you run into along the way!
>
> --
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