Blowing exhaust nightmare
Discussion
I have a 2004 rx8. When i replaced my clutch i took apart the exhaust, specifically the manifold to cat joint and the gasket came out and it was cracked and falling to bits and I could never reuse it. So exhaust was blowing massively, really loud, loss of power etc. Went to halfords and tried some holts fire exhaust paste, didnt work. Tried some new gasket material, didnt work. tried gasket material and paste, didnt work. tried crush washer gasket, didnt work. tried two of the flat normal style gaskets, didnt work. I've now tried copper gasket silicone and the two gaskets making a 3 layer sandwich of silicone and gaskets and let it cure for 24 hours, guess what, DIDNT WORK. starting to lose my sanity with this now, I have realised that the surfaces of the two mating joints are probably warped but I want to avoid getting a new manifold and cat as much as possible because it will be harsh on my pocket. The joints are what I believe to be an olive joint, they're essentially two plates in a triangle shape that sit against each other flush and 3 bolts and nuts in a triangle shape to secure it. I'm desperate for help before I torch the car and go into hibernation.
Do the plates face up well ? or are they not square to each other ? are they clean ? if you put a straight edge over them are they flat or warped ?
If the faces of the joint are no good, you could consider replacing it, an exhaust shop should be able to cut the joint out and replace the flanges or you could try a different type of joint:
Keep in mind, if the exhaust doesn't line up well these won't help you.
If the faces of the joint are no good, you could consider replacing it, an exhaust shop should be able to cut the joint out and replace the flanges or you could try a different type of joint:
Keep in mind, if the exhaust doesn't line up well these won't help you.
Crafty_ said:
Do the plates face up well ? or are they not square to each other ? are they clean ? if you put a straight edge over them are they flat or warped ?
If the faces of the joint are no good, you could consider replacing it, an exhaust shop should be able to cut the joint out and replace the flanges or you could try a different type of joint:
Keep in mind, if the exhaust doesn't line up well these won't help you.
everything has been taken off with a wire brush and they're completely smooth but I believe the joints aren't mating up properly as theres 1 specific point it seems to leak from the worse and I can visibly see a little gap at that point. Wouldnt the cost of having the joints replaced run me up to a similar amount of a new exhaust? If the faces of the joint are no good, you could consider replacing it, an exhaust shop should be able to cut the joint out and replace the flanges or you could try a different type of joint:
Keep in mind, if the exhaust doesn't line up well these won't help you.
ok, this is going to be a bodge. But is there anyway that you can get a jubilee clips around the two pieces?
Years ago on the e39 530, the downpipe had come away from the join. I also tried with the paste, clips, foils etc, and they all failed.
In the end I cleaned up both sides, again, reapplied new clean pastes, but then fused the two parts together with jubilee clips.
It worked, and I and held for the duration of owning the car, even passed MOT tests.
Years ago on the e39 530, the downpipe had come away from the join. I also tried with the paste, clips, foils etc, and they all failed.
In the end I cleaned up both sides, again, reapplied new clean pastes, but then fused the two parts together with jubilee clips.
It worked, and I and held for the duration of owning the car, even passed MOT tests.
starkslewis said:
everything has been taken off with a wire brush and they're completely smooth but I believe the joints aren't mating up properly as theres 1 specific point it seems to leak from the worse and I can visibly see a little gap at that point. Wouldnt the cost of having the joints replaced run me up to a similar amount of a new exhaust?
No, it shouldn't. Find a place that makes up exhausts and see what they say.XFRFred said:
ok, this is going to be a bodge. But is there anyway that you can get a jubilee clips around the two pieces?
Years ago on the e39 530, the downpipe had come away from the join. I also tried with the paste, clips, foils etc, and they all failed.
In the end I cleaned up both sides, again, reapplied new clean pastes, but then fused the two parts together with jubilee clips.
It worked, and I and held for the duration of owning the car, even passed MOT tests.
I dont think that would be possible on the joint I have Years ago on the e39 530, the downpipe had come away from the join. I also tried with the paste, clips, foils etc, and they all failed.
In the end I cleaned up both sides, again, reapplied new clean pastes, but then fused the two parts together with jubilee clips.
It worked, and I and held for the duration of owning the car, even passed MOT tests.
I suggest you unmount the rear part of the exhaust so that it is free to align with the engine part. Check whether the clamping flanges are closing the gap all the way around the joint. If they do, you should be able to seal it with any of the sealing methods you've already used. But if there's a gap, none of those is going to seal it. Assuming you can close the joint up, assemble it with whatever sealing method you're using and let is dry/set/cure as appropriate before you remount the exhaust.
GreenV8S said:
I suggest you unmount the rear part of the exhaust so that it is free to align with the engine part. Check whether the clamping flanges are closing the gap all the way around the joint. If they do, you should be able to seal it with any of the sealing methods you've already used. But if there's a gap, none of those is going to seal it. Assuming you can close the joint up, assemble it with whatever sealing method you're using and let is dry/set/cure as appropriate before you remount the exhaust.
I think that's my problem, it's not sealing properly If you can get the parts off the car it may be possible to hammer it all straight, but I'd worry why it bent and suspect it was because it was too weak for the loads on it. If the outside of the pipes is smooth enough to seal, you could simply grind off the flange from both sides and replace that with a sleeved joint. That's something you can probably do in situ.
If it wasn't blowing before you dismantled it & a gasket/sealing device that was in place to seal it fell apart why didn't you just get a new genuine one & fit that?
FWIW the system on my own car has one joint that has a bi-cone shaped steel sealing olive fitted between the ends of the two pipes that provides the seal. The rest of the system is Stainless but this isn't so needs to be replaced every few years.
The end of each pipe is flared & there is a triangular steel clamp on each pipe which join with three bolts. Simpler to use the proper item - takes less than 5 mins as it just needs 3 bolts undoing - than mess about trying to bodge.
The olive in mine looks much like this: https://www.ebay.co.uk/itm/Exhaust-Olive-Fitting-f... and there isn't a hope in hell that a flat gasket could seal the joint.
The olive also helps to take up any slight misaligment between the two sections.
FWIW the system on my own car has one joint that has a bi-cone shaped steel sealing olive fitted between the ends of the two pipes that provides the seal. The rest of the system is Stainless but this isn't so needs to be replaced every few years.
The end of each pipe is flared & there is a triangular steel clamp on each pipe which join with three bolts. Simpler to use the proper item - takes less than 5 mins as it just needs 3 bolts undoing - than mess about trying to bodge.
The olive in mine looks much like this: https://www.ebay.co.uk/itm/Exhaust-Olive-Fitting-f... and there isn't a hope in hell that a flat gasket could seal the joint.
The olive also helps to take up any slight misaligment between the two sections.
Edited by paintman on Monday 2nd December 09:42
PaulKemp said:
Get a grip...
£17.99 for a full kit on eBay
You spent more than this bodging it
Like I say, I've tried everything, this was the 2nd thing I tried, then tried crush washer gaskets, silicone, exhaust paste. I've now had two new flanges welded on and I still have the same problem, taken it back to exhaust shop and they say it's not blowing and they tried blaming it on a million other things other than exhaust. took It to another mechanic and they said they cant see any blowing but something sounds wrong with the exhaust but they dont know what. in the end I just got told to get a new exhaust £17.99 for a full kit on eBay
You spent more than this bodging it
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