[V6-12v] B4 head gasket replacement

[James Whitehouse]

Hi Tom, how's it going?

I did both my head gaskets a year and a half ago, they're not too bad a job on these. Worst aspect is access around the engine bay; do you have air-con?

Regarding the diagnosis; just check that there's no oil seeping down from above the head gasket line, and make sure it's not the rear cam seal dripping, however you're getting a leak in a classic place for the head gaskets to start seeping on these (rear/ rear sides of the heads).

If it is the head gasket, there's nothing I'm aware of that will stop it leaking apart from pulling the head and replacing the gasket. However, if it's not causing any other problems apart from making a mess, and smelling because of burning oil, you do have the option to leave it and just keep topping up the oil - how much is it losing? Just check that it's not blowing through into a water channel, or you're losing compression (look for either oil, or air bubbles in the coolant expansion tank).

If you decide to do the head gasket, personally I'd do both sides while you're in there and seriously consider replacing the hydraulic lifters while you're at it. It's given my V6 a whole new lease of life and it genuinely drives like new.

I would get the heads re-ground, it's not usually expensive and will save you having to potentially do the whole job again if they're not true. They don't tend to warp on the V6, but the gasket does wear into the head a little and it's just safer when you're going to all that trouble and expense.

Variable amount of seized bolt problems, apart from the downpipe-cat bolts, where the studs usually come out with the nut (not a problem, just put it back the same way, or replace the studs while you have the heads off). Generally depends on where the car has been (i.e. rust inducing environments, etc.) and who's worked on the car in it's history. I've not heard of any problems with the actual head bolts breaking, etc. though.

Only special tools you'll need are the cam/crank timing tools, but you should be able to hire those. I wouldn't attempt it if you don't have some means of raising the car up a ways (axle stands, etc.) because you do have to get underneath to loosen off the exhaust, etc. 

You could think of it as a good opportunity to go in there and replace some bits you otherwise wouldn't be able to get to easily. Definitely replace the *&£)*@ing valley pan gasket, you should get that gasket with the head gasket set. Make sure to replace valve stem seals and injector seals while you're in there too; they sometimes don't come with the head gasket set, so check. I renewed my knock sensors while I had everything apart, they are such a PITA to get to otherwise.

Time wise? Hmm... well it depends how many 'difficult' nuts/bolts you encounter really. If you have an easy time and don't encounter much in the way of seized parts possibly two or three days, factor in time to get heads re-ground, etc. If you have a few seized bolts, etc. say a week, or so?

Anyway, let me know if you need a detailed breakdown of the job. I can give you a blow-by-blow, or send you manual pages if you're definitely doing it.

Cheers,
James

--- On Sat, 12/7/08, Tom Christiansen <tomchr at gmail.com> wrote:
From: Tom Christiansen <tomchr at gmail.com>
Subject: [V6-12v] B4 head gasket replacement
To: "Audi Mailing List" <v6-12v at audifans.com>
Date: Saturday, 12 July, 2008, 2:33 AM

Folks,

The left side head gasket on my 1994 90S is leaking about 1/3 of the way
forward from the rear end of the engine. At least I assume it's the head
gasket. Oil is dripping onto the heat shield above the exhaust.

Is there a way to tell for sure if it's the head gasket?

Is there a cheap ghetto fix that would make it stop leaking for another year
or two?

What am I in for if I decide to attack the head gasket replacement? Broken
studs? Heads that will need to be planed? I'm pretty mechanically inclined,
have half a clue, and have the tools (except for tools to extract broken
studs), but I've never attempted anything this involved. How much time
should I expect it to take to complete the job on my own?

Thanks,

Tom
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