Front Exhaust Section needs replaced. Expensive? What to expect? ( 2010 Petrol N/A Forester)

[Peroni]

My 2010, Petrol, Manual N/A Forester was diagnosed today as needing a new front exhaust section. The garage say its the section from the manifolds to the flexible joint (roughly underneath front seats). Garage suggested I try to find aftermarket part or get a custom stainless steel pipe made since the Subaru part would be "funny money".

It has been blowing slightly for a while but getting worse of late. I had thought that it was just the join to the mid section needing replaced, since the joint looks crumbly. Was hoping that a bolt-on flex pipe would do the job. No such luck.

I shall double check it myself tomorrow, just to be sure, and I have booked an inspection with a local exhaust repair/manufacturer place on Thursday. I'm beginning to worry this could be expensive. ( I've just forked out £250 for a wheel bearing replacement and £450 for 4 new tyres, so this has been a nasty post Christmas expense) 

Any advice?  Should I try to source parts from a scrappy? How much work/labour is involved in replacing the front pipes? Will the cats and sensors being mucked about with trigger "check engine" warning lights? Should I do this work myself to save labour?  ( No garage but I've decent tools and am quite handy although I hate working under the car outdoors) 

[Mr B]

You just fit/weld a repair flange section in and fit new bolts/springs . worst case scenario on that join is both front pipe and centre pipe flanges are rotted and need replacing .
Decent exhaust specialist should sort that pretty easy, highly unlikely need replace whole front pipe unless well corroded .
Exact cost really depends on state of corrosion of your exhaust and whether you can get away with just front pipe flange side of joint needing replacement .

[Jamie_uk]

Can’t help much but I found aftermarket silencers on eBay for my 2010 Impreza rx when Subaru quoted over £500. Centre section I had sleeved as I couldn’t find a replacement online at the time and didn’t bother asking Subaru given the silencer price.
Developing issues with the front section now myself and haven’t found a single replacement online.

if it’s just the area around the joint and the majority of the pipe is sound you could remove it and have a new flange section welded on from a donor exhaust off another car or possibly get a piece online to fit to it 

[Jay762]

As mentioned I would see what the local fabricator says - welding a new bracket will be preferential to replacing cats. If you do go for a full replacement the engine sensors should not have an issue with any minor trimming to the air fuel mixture  

[Peroni]

Sorry for my slow replies. I don't seem to get notifications any more.

Thank you for all the suggestions. I wasn't able to get the car to the exhaust specialist today; had to cancel it because wife needed the car. Good advice re; not needing the whole front section. That would be a result! The front pipework looks OK from the rotted flange joint forwards, so hopefully a repair rather than a replacement.

I have bought a "flexi pipe repair" kit from Amazon and will have a go fitting that on Saturday.  I can't do welding. Only down side is that I will need to chop off the rotted front flange and also the perfectly good rear flange in order to fit the replacement part. It is stainless steel and from MIJ exhausts so should be decent quality. Another issue is that the front pipe is 54mm diameter and the rear/centre pipe is 60mm, so some bodging will need to take place.

Jamie; I've seen replacement front pipes on eBay, they are £667 though! (see pic below hopefully)

This is the repair kit I bought from MIJ:

 

eBay, replacement front pipework:

Found this picture on line but dunno if genuine part numbers or what?

 

 

[Mr B]

What I would suggest you do is not cut the front flange if it good condition, you would be far wiser get a pre cut flange (measure your flange bolt spacing) and taking that and your flexipipe to a shop and get them weld flange on (exhaust shop likely have a flange) then you got one side oem style which be far easier to fit and far easier/less problematic further down ownership line .

May seem like more hassle but it likely work out less long term .
also be sure as much as possible old pipe is inserted in the slip over joints or they will leak and be hard seal as lot more heat cycling back pressure and vibration/movement in this area all making it harder job make joins stay leak free .

[Peroni]

On 2/24/2022 at 10:06 PM, Mr B said:

What I would suggest you do is not cut the front flange if it good condition, you would be far wiser get a pre cut flange (measure your flange bolt spacing) and taking that and your flexipipe to a shop and get them weld flange on (exhaust shop likely have a flange) then you got one side oem style which be far easier to fit and far easier/less problematic further down ownership line .

May seem like more hassle but it likely work out less long term .
also be sure as much as possible old pipe is inserted in the slip over joints or they will leak and be hard seal as lot more heat cycling back pressure and vibration/movement in this area all making it harder job make joins stay leak free .

Thank you Mr B. I had kind of wondered about that issue.

Rather annoying that I could not get down to my exhaust repair centre on Thursday to have them look at it. No doubt they would have recommended what you said. They seem to be geared up for repairs/fabrication and can source full S/S systems too.  It is weeks between appointments there. I didn't know that a "pre cut flange" was a thing. I get what you are saying about having one side as standard and no doubt there are good engineering reasons for having that kind of sprung, doughnought, spherical joint flange thingy as standard.

I have a 60mm - 54mm reducer. I could maybe use it to keep the side 60mm rear/centre pipe as standard by inserting it inside the "good" pipe. Bodging it until the pros can work on it properly. Can't quite think how to get a good seal though. 

Edited February 26, 2022 by Wulbert
naughty word

[Peroni]

Went back to exhaust repair place...they can't even look at car until 8th March! , so a home repair is on the cards. Only other places in town are Kwik-Fit and National Tyres who, I'm assuming will just want to replace with brand new parts (that I can't really afford right now).

It seems a shame to slice up the middle section pipe/flange because it looks sound (on the right in picture below). It's the front pipe's flange ( left hand side) that has failed. I'll cut that off and see where that leaves me. Dunno why the spring bolts were tightened right up...surely that defeats their ability to accommodate expansion in the joint?

[Jamie_uk]

Keep the centre pipe and flange. could try getting a flange section slightly bigger than front pipe online and a pipe connector.

Put front pipe inside and clamp to pipe and new flange to hold it, drill flange if needed to match up with existing centre pipe one.

chew on but might work and get you by till properly repaired and won’t need to get any work done to the centre pipe. Plus if works out well it might last a good while. 
 

done a few silly fixes to get through MOT, went a year after my rear silencer pipe sheared off the box clagged a full pot of gun gum on it to hold it on the night before got through MOT without even an advisory haha 

after that riveted some 90 brackets on and sealed up, then it’l sheared from the flange on the centre pipe, steel wire wrapped and sealed. Lasted till my next MOT till I found a replacement on eBay for 15% of Subarus cost. 
 

had centre sleeved near front joint last year, had a good run of about 3 years but the times come potentially for a replacement sadly. 

[Mr B]

Your only real option of good home repair is buying a flanged repair section that slip over the front pipe and be clamped as expanded slip joint and bolts to the centre flange.
See eBay link to get idea of what you want to achieve this: https://www.ebay.co.uk/itm/233362362813

You can use exhaust joint paste or a high end polyurethane sealant with some success but this area of exhaust harder seal due to heat and back pressure at play.
You don't really want cut the flange off centre pipe as it perfectly good although not end of world if replaced with decent option and installation
This is a super easy fix for any half decent garage and for exhaust shop that does fabrication it even simpler as they will have lot of stocked parts and this is gravy work for them .
We do a fair few of this on all models as a common failure area on older cars and more so in heavily road salted areas such as Scotland .

Personally I would suggest you save money by avoiding temporary repair unless can do a worthwhile option/effort and get it sorted at garage as a repair to existing front pipe.
You most certainly don't want any new front pipes if can be avoided and you also want avoid aftermarket especially cat sections as fit and function along with quality is not even close to factory oem .
 

[Peroni]

I'd kind of hoped that by turning up at the exhaust place this morning, with the car, that they might just take a quick look at it and decide it was a 30-min job. No such luck, they are snowed under and the chap seemed quite stressed out. It's booked in for 8th March, earliest I could get.

An unpleasant couple of hours stretching under the car with angle grinder and reciprocating saw etc.  Here's what I ended up with; I cut off the rotted flange from front pipe and the small reducer part I had bought was a decent fit to both pipes. So, rather than fit the flexi S/S section ( which I might still do later) I just sleeved both pipes with the reducer, using some stove pipe fabric sealing tape and the exhaust sealer that came with the flexi kit. It all seems a good tight fit, but I'm a bit worried that it's not flexible enough to accommodate vibration & heat. We will see.

Hopefully this will last until the exhaust place can do a decent, professional repair with a new flange on the front pipe.  The mid section seems in decent condition although the flange holes are a wee bit corroded.

A rattle from the front pipe under the engine bay turned out to be a loose heat shield. I fitted new bolts to that, but it still feels like it will work loose again. It seems to only fix to itself.  It's all sounding a lot quieter now.

Strangely, I destroyed two brand new reciprocating saw blades cutting through the exhaust flange and bolts. Is it a particularly hard steel? Maybe my method was wrong and I overheated the blades by cutting at full speed? They were Makita branded blades, so I expected better.

Thanks to all for the helpful advice. Especially Mr B. I was ready to cut the rear pipe's flange off without this advice.

 

[Peroni]

3 hours ago, Mr B said:

Your only real option of good home repair is buying a flanged repair section that slip over the front pipe and be clamped as expanded slip joint and bolts to the centre flange.
See eBay link to get idea of what you want to achieve this: https://www.ebay.co.uk/itm/233362362813

You can use exhaust joint paste or a high end polyurethane sealant with some success but this area of exhaust harder seal due to heat and back pressure at play.
You don't really want cut the flange off centre pipe as it perfectly good although not end of world if replaced with decent option and installation
This is a super easy fix for any half decent garage and for exhaust shop that does fabrication it even simpler as they will have lot of stocked parts and this is gravy work for them .
We do a fair few of this on all models as a common failure area on older cars and more so in heavily road salted areas such as Scotland .

Personally I would suggest you save money by avoiding temporary repair unless can do a worthwhile option/effort and get it sorted at garage as a repair to existing front pipe.
You most certainly don't want any new front pipes if can be avoided and you also want avoid aftermarket especially cat sections as fit and function along with quality is not even close to factory oem .
 

Thanks for the eBay link Mr B.  Yes, those flanged repair sections looks a better solution that the flexi bolt-on stuff. ( I always wonder if those exhaust clamp things attract corrosion and speed up rot)

[Mr B]

Potentially yes as moisture and minerals can collect around it and get drawn in via capillary action .
Reality is at this vehicle life point it not a big deal, any type of half decent repair here going outlast the next major exhaust failure that requires larger repair/replacement solution .

I have used a few flanged repairs that flange one end and clamp the other to save owner buying a cat when metal too poor condition risk welding and they lasted well, one I done close to 4 years ago and was fine when done last mot pre inspection and service work .

Done well and in the right instances they very cost viable and will last .

[Mr B]

2 hours ago, Wulbert said:

I'd kind of hoped that by turning up at the exhaust place this morning, with the car, that they might just take a quick look at it and decide it was a 30-min job. No such luck, they are snowed under and the chap seemed quite stressed out. It's booked in for 8th March, earliest I could get.

An unpleasant couple of hours stretching under the car with angle grinder and reciprocating saw etc.  Here's what I ended up with; I cut off the rotted flange from front pipe and the small reducer part I had bought was a decent fit to both pipes. So, rather than fit the flexi S/S section ( which I might still do later) I just sleeved both pipes with the reducer, using some stove pipe fabric sealing tape and the exhaust sealer that came with the flexi kit. It all seems a good tight fit, but I'm a bit worried that it's not flexible enough to accommodate vibration & heat. We will see.

Hopefully this will last until the exhaust place can do a decent, professional repair with a new flange on the front pipe.  The mid section seems in decent condition although the flange holes are a wee bit corroded.

A rattle from the front pipe under the engine bay turned out to be a loose heat shield. I fitted new bolts to that, but it still feels like it will work loose again. It seems to only fix to itself.  It's all sounding a lot quieter now.

Strangely, I destroyed two brand new reciprocating saw blades cutting through the exhaust flange and bolts. Is it a particularly hard steel? Maybe my method was wrong and I overheated the blades by cutting at full speed? They were Makita branded blades, so I expected better.

Thanks to all for the helpful advice. Especially Mr B. I was ready to cut the rear pipe's flange off without this advice.

 

With one of the flanged repair sections with flange one end and expanded other end for clamp you could do quality long term repair yourself .
The bolts would be grade 10.9 .
Only blades we have much with a carbide tipped, spendy but do job quick and neat .
You done the hard work, I would go for the glory and get yourself a repair flange section and save yourself a garage bill and treat the wife to a box of chocolates lol .

[Peroni]

1 hour ago, Mr B said:

With one of the flanged repair sections with flange one end and expanded other end for clamp you could do quality long term repair yourself .
The bolts would be grade 10.9 .
Only blades we have much with a carbide tipped, spendy but do job quick and neat .
You done the hard work, I would go for the glory and get yourself a repair flange section and save yourself a garage bill and treat the wife to a box of chocolates lol .

Good idea! I might just do that.  

What goes in between the flanges? Is it some kind of compression gasket? And the bolts are just called "exhaust flange bolts" with springs, or something?

[Mr B]

Well originally it a tapered end doughnut that sits on a snub of the front pipe, idea of this and the springs is spring provide fixed tension and tapered end dougnut allows some angle variation and whole concept has some vibration/expansion ability .
You won't be able reconstruct it to be exact same principle but it not a big deal, the flange joint will need a metal graphite gasket (examples link) just use some 8.8 grade bolts/nuts and decent thick washers .
The good thing with the clamped slip joint is that allows small degree of alignment angle change and some expansion and vibration relief .
On the slip joint the slits should be at 90degrees to the u bolts nuts as outer pipe closes better that way as tighten u bolt clamp and it tends reduce tendency of small leaks at the pipe slip joint slits .

You going want fairly long repair flange pipe 8" being minimal , The front pipe larger expanded diameter would be removed and your repair pipe would be chosen to fit over the slimmer main diameter .
Easy job if measure up and buy parts wisely . Cheap too and Russia mess going be costing us all enough 😕

[Peroni]

On 2/26/2022 at 8:46 PM, Mr B said:

Well originally it a tapered end doughnut that sits on a snub of the front pipe, idea of this and the springs is spring provide fixed tension and tapered end dougnut allows some angle variation and whole concept has some vibration/expansion ability .
You won't be able reconstruct it to be exact same principle but it not a big deal, the flange joint will need a metal graphite gasket (examples link) just use some 8.8 grade bolts/nuts and decent thick washers .
The good thing with the clamped slip joint is that allows small degree of alignment angle change and some expansion and vibration relief .
On the slip joint the slits should be at 90degrees to the u bolts nuts as outer pipe closes better that way as tighten u bolt clamp and it tends reduce tendency of small leaks at the pipe slip joint slits .

You going want fairly long repair flange pipe 8" being minimal , The front pipe larger expanded diameter would be removed and your repair pipe would be chosen to fit over the slimmer main diameter .
Easy job if measure up and buy parts wisely . Cheap too and Russia mess going be costing us all enough 😕

Thank you for the detailed guide. Apologies for the very slow reply!