Small leak in exhaust system

Post by **GlennG2759** » 12 Mar 2020, 07:28

I have a small leak in my exhaust system on my '06 V70. From my experience exhaust manifold leaks are usually associated with a ticking sound, which I don't have, so I think it's in one of the pipe joints. Has anybody ever used the shop vac or leaf blower in the exhaust pipe, while spraying joints with soapy water method. Since I have to get this vehicle up in the air on all fours at least 18" to get myself under thereI only want to do it once, even if it means replacing stuff. Are those stainless steel flex joints before the cat a known problem. 105k miles on car. Any advice appreciated. Thanks Glenn

Post by **oragex** » 12 Mar 2020, 07:43

100K miles is a bit early for the flexible downpipe to leak. The other place is at the flange between the catalytic c and the first muffler. It's actually the flange on the cat side that wears at the bottom and starts leaking - so the gasket no longer seals. Only way is to grind to resurface the flange. The studs may need drilled and replaced at this flange, while at the exhaust manifold usually just need removing (and replacing) the 4 nuts.

Post by **abscate** » 12 Mar 2020, 07:44

How about some seafoam or Marvel Mystery Oil into the vacuum tree to see if you blow smoke from a joint?

(Wait , that last phrase doesn't look legal yet)

tick tick is usually a blown EM gasket

Throaty roar - loose joint either post cat or the flex joint right after manifold. You can see that one easily of you remove the metal cover for the preheat, and replace those M8 bolts with new ones since they will be rusty

Post by **- Pete -** » 12 Mar 2020, 10:02

Like Oragex pointed out, look in that vicinity, but also at the resonator (just rear of the cat/flange). The resonators rot out seemingly more quickly than the remainder of the exhaust. No big deal, just cut it out and replace with 2.5” pipe.

2.5” OD pipe will just slide right over the back of the flange as well as the remainder of the exhaust piping - you will not need any adapters, unless it’s an R exhaust.

The flange, also as Oragex mentioned, in front of the resonator will likely need to have the studs cut off & and holes drilled. If you separate at this joint you’ll need to make or buy a new gasket. I’ve made gaskets out of high temp header gasket material, but you can buy online too. $5-6 from IPD.

https://www.ipdusa.com/products/11920/1 ... 45-9179056

The flange is ferrous so you can weld pipe right to it, but make your cuts on the resonator as close to the ends as possible. The pipe itself is not magnetic, but I was able to MIG the 2.5” parts store exhaust piping right to the SS Volvo pipe.

The bonus is you get a little nicer sound coming out the tailpipe

Not louder though.

The hangers towards the rear rot out as well. If they are rotted the exhaust forward from there can sag.

: 7D883EE4-E028-4D31-B462-C95E31CA5A15.jpeg (142.84 KiB) Viewed 3246 times

Edit:
I’ve done 3 salt country P2 exhausts & the resonators have all been rotted. The final muffler (right before tailpipe) gets a little flakey on top, but I haven’t seen one rust completely through yet. I have seen photos of completely rotted ones though.

The flex joint Chinese finger trap exterior unravels but the accordion joint is pretty tough. But definitely look closely at it as it does “flex”.

Can you hear an exhaust leak or on cool mornings do you have exhaust steam coming up from before the tailpipe? Just curious how you’ve determined there exists a leak.

Post by **GlennG2759** » 12 Mar 2020, 12:20

After getting under and looking as close as possible it looks like resonator to cat pipe flanges are rotted pretty good. That also seems where noise is coming from. I like Petes idea if eliminating resonator and replacing with 2.5 pipe. Thanks all for replies, now I just have to get high enough off the ground to work comfortably.

Post by **- Pete -** » 12 Mar 2020, 13:48

I usually start with a 3’ chunk of 2.5” & then cut it down to an appropriate length.

Post by **oragex** » 12 Mar 2020, 15:13

Also gently with those alu heat shields, they rot at the bolts and are very rattle friendly

deano1 · Post by **deano1** » 13 Mar 2020, 13:39

Nice Job on the resonator delete job Pete!
Almost exactly what i did and I agree with you 100%,,, exhaust note turns brilliant @ 3000rpm B5244S!
I highly recommend!!
Cheers

Post by **- Pete -** » 14 Mar 2020, 00:34

Not applicable to FWD, but another added bonus on top of exhaust note is permanently resolving the potential for rain-squeal.

deano1 · Post by **deano1** » 14 Mar 2020, 15:59

Ummm...
What's "rain-squeal"?