[V6-12v] B4 head gasket replacement

Mon Jul 14 02:59:23 PDT 2008

Tom,

If it's the valley pan gasket, and seeping heads, you may as well pull the heads and have done with it; you don't actually have to go as mad as I did and replace everything. If it's eating that much oil and leaving a mess on the garage floor, I don't think ignoring it is an option!

I hear what you're saying though. It is a quandary with these cars, because they do drive so well when the work's done on them, it's hard to know when to quit. When you get to the stage you're at, with fairly major work to be done, you do have to decide whether you want the car long term or not. It's a toss up between having a very nice car which is definitely worth less than you'd be spending on it, but also whether you can afford something significantly newer, which won't need all this work soon, and which drives as beautifully. Also, whether you actually love these older Audis, or whether it's just another car...

You're certainly right that once you start doing things, the list ploughs on and on. I did the head gaskets around 1 1/2 years ago and replaced everything, and I mean everything, in and around the top end, including any suspect electricals (read knock sensors, etc.), clutch, belts, etc. Then it needed a front suspension rebuild - shocks, top mounts, bushes, etc. The stiffer new shocks caused the track rods to finally let go, then the ARB links needed replacing. If I was being fussy (which I am), I'm going to do the rear suspension (now feels too soft when cornering compared to the new fronts), repair the central locking, fit a new brake master cylinder and bomb, etc., etc. This is all over and above normal servicing.

Well, let us know what you decide!

James

--- On Sun, 13/7/08, Tom Christiansen <tomchr at gmail.com> wrote:
From: Tom Christiansen <tomchr at gmail.com>
Subject: Re: [V6-12v] B4 head gasket replacement
To: james_whitehouse1 at yahoo.co.uk
Cc: "Audi Mailing List" <v6-12v at audifans.com>
Date: Sunday, 13 July, 2008, 5:52 PM

James,

Well aside from the car leaving a mess in the garage and leaving an occasional smoke trail on the road, it's going quite alright. Life's grand overall.

I crawled around under the car yesterday. I didn't have it up on jack stands, but I was able to get a better idea of where it's leaking. It seems to mostly be the valley pan gasket. That's definitely leaking enough on the left and rear sides that it's making a big mess. I couldn't get a good look at the rear end of the left head gasket (A/C in the way) but judging from the mess, I would not be surprised if it is leaking. The right side head seeps a tiny bit. Enough to make the engine black and attract dust, but not enough to make a mess. The car goes through 1qt/1L of oil in 3-400 miles easy. Automatic oil change... Hey. That's a feature... :-)

I might declare the car dead, which is unfortunate because it still drives well. But I see the telltale signs. The steering is using a bit more fluid these days. Not dramatically, maybe from max to min on the reservoir 1.5-2 times per year. But that's more than it used to. So another "while I'm in there" item would be a steering rack + hoses. That triggers an alignment. And I really should get new tires before rain season sets in. So it adds up. I'm offered $1300-1600 as a trade-in. That's probably what I would end up spending in repairs. Granted, the car would run even better after that, but still. In about 12k miles it would need a timing belt and associated stuff. How long does one keep pushing on?

As far as rusted bolts go. The car was driven for the first ten years in California. Then in Washington State (Seattle area) since then. So it's never seen salt. There's no rust. Except for one of the exhaust hanger bolts, I've never had a stuck bolt on that car. 

Anybody interested in a parts car?? (half serious here).

Thanks,

Tom

On Sun, Jul 13, 2008 at 2:39 AM, James Whitehouse <james_whitehouse1 at yahoo.co.uk> wrote:

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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