Exhaust leak on 2004 xc70

[cantabrian]

Hi, folks,

I'm new to the xc70 world, and it's been great learning about the car on this forum. Been really helpful. I bought a high mileage (170k) 2004 xc70 about a month ago, and I've been slowly working on checking it completely over, doing everything suggested on this forum.

But I have a problem. Basically, I have an exhaust leak. But, weirdly, it's one that mechanics didn't pick up in a pre-purchase inspection or in a post-purchase inspection. (Well, in the pre-purchase, the mechanic mentioned that there's a very slight leak in the "donut gasket"--which I suppose was non-Volvo speak for the connection to the turbo? Or to the exhaust manifold?) The pre-purchase inspection wasn't done by my mechanic, but my mechanic said a month ago that there didn't seem to be a noticeable exhaust leak.

Anyway, I think they missed it because the leak isn't readily apparent once the car's been driven on any given day. First thing in the morning, when you start the car, there's a motorcycle-like rev initially, then car's loud for the first 10 seconds or so, then it quiets down as the rpms go down. While driving, it's a very faint sound. Like a faint buzz. You can hear a mild version of the sound on start up here: https://www.dropbox.com/s/g7bh5qduzpklu6f/1.m4v?dl=0

Worried that this might be something that might screw with the catalytic converter, I got under the car last night and saw what looked like a cracked flex pipe. The flexy part is torn. But I'm not sure the pipe underneath is. You can see that in this video here: https://www.dropbox.com/s/1x19bamidhm6ir2/2.m4v?dl=0

Thinking it was the flex pipe, I called a local exhaust guy today see if he could cut if off (since it's part of the cat) and put another one in. I gave him all the symptoms. He said that it sounded like the exhaust manifold. He said that's the only thing that can go quiet after 1-15 second. And that a flex pipe wouldn't be quiet as I drove. Is that right?

After talking to him, I decided to get under the car again this afternoon. And when I did, and started the car, I didn't see anything coming from the manifold area (though I didn't inspect it visually, as I didn't take off the heat shield) or from the flex pipe. But I did see some white smoke coming from the region of the cat itself. Ugh. See this video: https://www.dropbox.com/s/htgoi2f6qgihmpy/3.m4v?dl=0

In the video, I say "steam." But that doesn't seem right. Seems like smoke, right? If so, is this a better or worse problem than a manifold/flex pipe? Maybe just a small crack in the cat? Does that third video raise alarms for you like it did for me? I should note that there was more smoke before the video started. I started it late.

So, basically, I'm coming to all of you to see how I should proceed. Just take it to an exhaust guy, I guess, and have them look it over. But I figured I'd ask here first. I can't weld, but I do like to be informed before going in for service. Plus if it seems like maybe a variety of things, I could price them out at the local salvage yard.

Any help or advice would be much appreciated. The code is not showing any codes. I have an icarsoft i906, and I ran a test this morning on fuel trims. It checks out fine.

At the end of the day, if it's just an annoying noise, then I'm ok to leave it for a while. But if it's going to affect performance more broadly, I thought I'd take care of it. (And this says nothing about the fact that I still need to look at the turbo, which I'm worried about. The car doesn't have a boost gauge, but I'm not sure I hear the turbo spooling up. There's oil on it, and also oil vapor residue on both ends of the charge pipe. But one thing at a time! PCV passes the glove test, but I haven't done boost tests yet.)

That's it. Sorry for the long post.

[cantabrian]

One more thing: while trying to look back at the exhaust manifold, I noticed this on the back of my engine. Forgive my ignorance; I'm just learning my way around the engine. But what is this (in this video), and why is there oil on two spots?: https://www.dropbox.com/s/mvy81lshalw0w2q/4.m4v?dl=0

[jonesg]

You say theres oil on the turbo?
and the cat is smoking a bit?
The turbo could be passing oil down the exh into the cat.
Mine did that recently, soon after the shaft in the trubo broke. You can get a new turbo core for $175 on ebay.
Pull the turbo inlet pipe and feel the nose of the compressor fan, check for slop.
Should be very slight side wiggle as the bearings float in oil when running but nothing more.
Either way, its not the end of the world, just a bit awkward getting it swapped out.
White smoke could be coolant leaking from the turbo, mine had the same symptoms, white and blue smoke on startup.
I have a 2004 v70, pretty much the same.
Give me a yell if the turbo breaks , I can steer you toward the turbo rebuild kit.
I'm not too far , S. MA and can help if need be.
Cheers.

[NinaYo401]

Pretty sure my flex pipe or something in that vacinity just took a shit on my 05 xc70 this week, which happens to coencide with having the motor mounts replaced.

Been seeing some moisture in the exhaust. I tends to leave a wet condensation ring where she sits, if left idle

[abscate]

Old thread alert.

[NinaYo401]

17° out this morning started my car in the dark with a flashlight before work. Figured I’d see some exhaust leaking or feel something with my hands on the manifold. Nothing Blowin

So later on, hours later, coldstart. Peered between heat shield & firewall, Just below or very low on the Flexi pipe, I could see wafting exhaust fumes

Dropped by a local custom exhaust shop who does auto repairs, who doesn’t have a chance take a look at it till Monday

[abscate]

ITs really hard to do welding underneath without a lift. Fire, flammables, and confined spaces just don't mix

I managed to do my 99 weld but it was easy to access, otherwise, its the indie.