98 V70 exhaust leak diagnosis

[oragex]

Hit hit the nail on the head about the clamped connections. The connection right after the catalytic converter and forward of the muffler is leaking like crazy...almost like there is a hole in the muffler. Is it supposed to leak like that? The amount of air coming out of the joint was as if there is an 1/8 inch gap all around...a lot of air was coming out of the joint.

I had the same leak at the flange between the cat and the first muffler. In fact, the metal had 'worn' so the two joints weren't making contact any more even despite the gasket. The best way to deal with this is after one side is tossed, build some metal with a welding machine on the pipe surface then grind it down until the pipe section is flat again.

[98v70dad]

Good question to which I can say I just don't know the answer to. I can't think what damage it could cause as exhaust gases come out the end and there are no one way valves in the muffler. You might want to remove the spark plugs to allow pressure to dissipate if a valve is open and not pressurise the block. I suppose you could leave the plugs in but don't go crazy on the pressure or length of time you subject the engine to.

Use a piece of tissue attached to a short stick to give you the ability to move it around the manifold and muffler to find any leaks. Make sure you try to get it under the manifold and the gaskets to the cylinder heads.

Neil.

I used your tissue paper on a stick trick about a month ago and it seems that the manifold is leaking from the two cylinders closest to the drivers side. However, I found testing in this way to be inconclusive for my situation. I got the sense that the waving tissue MAY have been from the cooling fan...it was pretty hard to tell. At any rate I suspect that I may have a gasket leak there or I may have a crack there or both. I thought I would repeat the shop vac test after I've sealed up the post-cat pre-muffler leak and "see" what I can hear..

[scot850]

interesting to see what happens with the shop vac version of the test and the tissue on a stick.

Neil.

[98v70dad]

interesting to see what happens with the shop vac version of the test and the tissue on a stick.

Neil.

Can you tell me how tight that post-cat, pre-muffler joint is supposed to be (apparently there is no gasket there)? Mine was leaking A LOT of air but I'm pretty sure the shop vac is a little higher pressure than just unrestricted exhaust running through the pipe.

Also, I checked FCP euro and they sell new volvo OE clamps pretty cheap but the note says the price is for half a clamp (the issue of new fasteners is left to your imagination-no mention of them) but the picture shows a full clamp. Any idea what the norm is ..who would want just half a clamp and maybe/maybe not new fasteners? There's a non-OE part where you apparently get everything you need. Since this joint has no gasket and relies on fit I'd be hesitant to buy aftermarket though.

I know I can call them but thought you might know since you seemed to have some experience with this.

[scot850]

Volvo sells the 2 parts separately, as well as the 2 bolts. Clamp part numbers are: 3507702 and 3507703. Volvo list the bolts as 982793. When I bought those for my V70R, the bolts were way too long and had an un-threaded section which prevented you tightening them fully. I had to use 2 bolts with full length threads I had kicking around to make it work. If they try to sell you the bolts, check they will work first!

Neil.

[cn90]

With the car this old (20 years old), chances are the Clamps are rusted and it will be a futile effort to fix it.
Best is to ask a muffler shop to cut the damaged section, find an appropriate pipe and weld it in as a sleeve.

[mecheng]

With the car this old (20 years old), chances are the Clamps are rusted and it will be a futile effort to fix it.
Best is to ask a muffler shop to cut the damaged section, find an appropriate pipe and weld it in as a sleeve.

Had the same leak, do this! The clamps are rotted to hell. Tell them to use SS. $80 for my local shop and it is sealed perfectly.

[98v70dad]

With the car this old (20 years old), chances are the Clamps are rusted and it will be a futile effort to fix it.
Best is to ask a muffler shop to cut the damaged section, find an appropriate pipe and weld it in as a sleeve.

Remember, this car has lived its entire life in Atlanta, GA. We don't have any road salt except for maybe once every 5 to 8 years. I'm from the rust belt and I understand your comments about a rusted exhaust. I've been under the car and have looked at the area in question. The clamp seems fine. There is some surface rust but it doesn't appear to be any worse than that. There is no rust evident on the catalytic converter or exhaust or muffler. There is some surface rust on the exhaust manifold. I would call the condition remarkable for the age of the car. Atlanta GA isn't the rust belt. I know exhaust systems sometimes rot from the inside out. It all seems sound - determined by tapping on it. I guess I'll find out when I take off the clamp.

My daughter used to regularly drive the car over medians and curbs so my thought is that she just pulled the joint apart a little. Its also not uncommon here to hit some substantial road debris at 70 mph. It happens quite often and is usually unavoidable.

Anyhow, the welded sleeve is a good idea if I need it, but I don't think I will - I've been wrong before.

[98v70dad]

Volvo sells the 2 parts separately, as well as the 2 bolts. Clamp part numbers are: 3507702 and 3507703. Volvo list the bolts as 982793. When I bought those for my V70R, the bolts were way too long and had an un-threaded section which prevented you tightening them fully. I had to use 2 bolts with full length threads I had kicking around to make it work. If they try to sell you the bolts, check they will work first!

Neil.

The parts list show M8 1.25 x 15mm with flange nuts. I was able to buy M8 1.25 x 16mm with flange nuts and full length threads at the hardware store. I bought the next size (diameter) smaller also to to be sure since the specified size looks a bit large.

[98v70dad]

With the car this old (20 years old), chances are the Clamps are rusted and it will be a futile effort to fix it.
Best is to ask a muffler shop to cut the damaged section, find an appropriate pipe and weld it in as a sleeve.

Had the same leak, do this! The clamps are rotted to hell. Tell them to use SS. $80 for my local shop and it is sealed perfectly.

I've already inspected mine. No rot at all - only mild surface rust. Maybe removing them will surprize me but it doesn't seem that there is much rust at all.