Exhaust leak/fix suggestions

[Sjwillis]

In true scope creep, I had the shop vac out to do a cooling system flush this AM and thought "hmm, maybe I'll try to find the exhaust leak while I'm back here with the shop vac" Blowing air through the exhaust revealed a leak where the exhaust mounts to the engine (inconveniently underneath my AC).

It does feel like the leak is at the gasket where the exhaust meets the engine so perhaps just replacing the gasket would solve this?

However, looking at how this piece of exhaust is mounted in Bentley it looks like a bolt should be going into the head but instead this looks like it's coming out of the head with a nut on it.

Given that the top appears bent, any thoughts on a possible fix here? This feels like it may be beyond my driveway skills but I'm nervous about just taking it to any old shop (see my post from last week about the local boutique auto shop putting my fuel filter on facing the wrong direction!)

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1986 Wolfsburg Weekender
1972 MGB

[Phishman068]

That's a tricky job- id take it to a premium and trusted mechanic or a place with known vanagon experience.

Rusty exhausts can literally total the engine, and more often then not now if I'm looking at something like that- I take the engine out of the vehicle to work on removing the exhaust. I've found over the years that it reliably adds about 3 hours to the job to remove the engine completely, vs that one stud's ability to take 3 or 4 hours on a whim, and then the next one do the same, etc etc etc.

That's a risky job. I've seen more than a few where a bolt broke off, then when drilling it- drilled off center, or broke the drill bit off in the head.
I've seen multiple times where just replacing an exhaust gasket resulted in a needing at least one new head, at which point, it starts making sense to do an engine rebuild.

That $2 gasket can cost $2000-3000 when it's all said and done, I've experienced it first hand several times.
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http://www.thesamba.com/vw/forum/viewtopic.php?t=559766&highlight=winter+rust
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http://www.thesamba.com/vw/forum/viewtopic.php?t=569774
http://www.thesamba.com/vw/forum/viewtopic.php?p=6864936#6864936

"Along with the ability to go fast, one looses the desire to hurry."

[IdahoDoug]

I agree with the above post. It's clear someone incompetent has been in there as they did not reassemble properly (note bracket with hole that's supposed to be on that lower stud. The wrong nuts were used (supposed to be a rust-resistant copper coated nut, which is commonly available), and obviously they banged it into something reinstalling and bent the stud, which is why it's not providing the proper pressure there. In turn, that lack of pressure is why the gasket failed there. You can actually see the gasket has frayed into separate layers and there looks to be a visible air gap.

Given the rust, this is likely to be a snapped stud or two. Given an average shop, they'll give the "remove the rusty exhaust" task to an inexperienced tech as it's a crappy, nonrewarding job. However, the $2000 final expense will make it of interest to them to take on the job.

I'd say an exhaust shop would be your best bet as they're used to dealing with this. But be ready for a massive bill over a simple gasket replacement. Typical of exhaust work in a rust belt location.
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1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[zerotofifty]

Soak in penatrating oil over night. then using a box wrench try backing out the nut with the stud. It might simply back out. If that fails, a torch on the aluminum head around the stud can assist loosening. Id at the least try MAP gas rather than propane, but oxy acetylene is preferred for best pin point heat You need to heat the head faster than the stud, pin point heat allows this to happen.

Do NOT over torque if jammed, you dont want to shear off the stud.

Access might be improved by moving the AC compressor off to the side, so you can tackle this from above

If stud wont back off, you may cut the stud nearly flush with the nut, then the nut might come off the stud, if not then split the nut with a cut off wheel

Upon reassembly, use the copper plated, all metal split locking nuts. these resist sticking, and the split lock feature assures they wont rattle loose Use copious amounts of antisieze. a bolt rather than stud may help facilitate install of the exhaust manifold,

Do not ignore this leak, vans with oxygen sensors will sense this leak and then enrichen the mixture to compensate for the leaking in of oxygen. rich running will in turn harm the motor, and destroy the catalyst. Do NOT ignore this leak. Catalysts can cost near $700 if you are required to use the california style.

Copper plated exhaust nuts....
https://www.mtmfg.com/part/view/lock-nut-set-8mm-1...20Products
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[MarkWard]

I've seen both exhaust bolts into the head, exhaust studs with nuts or a combination of both. My preference is studs. It is too difficult to start bolts through a warped exhaust without cross threading. You can almost always get the exhaust over the studs.

I appreciate that you are doing some spring cleaning, but if a stud vs a bolt is confusing, as others have suggested have a pro do this job and really examine the complete exhaust. It might be worth while to install a new exhaust because a good part of it will need to be removed.

There was a thread in the last couple years where a member decided not to take the advice and openned a can of worms that I'm pretty sure needed replacement heads and I don't recall if it ever got back on the road. So, you have been warned by a few of us. Good luck getting it sorted.

[zerotofifty]

[Sjwillis]

As always, super grateful for the collective wisdom of this forum. Hodi's Garage is about 45 minutes from me and he has a really good reputation with VWs so will see if he might take a look at my problem here.
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1986 Wolfsburg Weekender
1972 MGB

[Wildthings]

Hacksaw the stud off just past the nut and then use an oxy-act rig to heat the nut, it should come off in seconds.

Having at least one stud for each flange makes the job go easier. If you need to replace a stud, sourcing a quality stud from BMW or Mercedes will mean less problems down the road. Use copper flange nuts and put a stainless acorn nut over the projecting part of the stud to keep oxygen away from the threads.

[Klister]

[Glenn]

I've built quite a few Type 1 engines and take price in not snapping hardware during disassembly.

Penetrating oil, heat and time are what is needed.

If you rush it, you'll snap the stud. If that happens, weld a nut on the stump and try again. The aluminum head will expand quicker than the steel stud. The stud needs to be removed, clean the threads with a "thread cleaner" and not a tap. Install a new stud and you'll be back in business.
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Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"

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[campism]

Having gone through this once and due to repeat the job years later now, my advice is to expect at least one of those studs/bolts to break. Removal of the remains can be tricky and might result in pulling a head to have a machine shop do its magic. Good luck with this project. I did mine in a gravel driveway in Virginia in August and survived, but it was extremely not fun.
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'87 Westy in Wolfram Grey Metallic, tragically crushed by a falling hickory tree in my own driveway and now gone, leaving me Vanagonless and with no plans to replace it, alas.