Muffler Repair Recommendations [ 1997 Volvo 850 GLT ]

[oughorian]

I'm sorry but forget about that muffler it's total, any atempt to repare it's just wasting time and money I know that will be a expensive but some time there is no other logical way.

[1997volvo850]

There's cheap and then there's stupid. Spring for the new muffler Ebenezer.

Stupid? I've always thought spending $400-500 dollars when I didn't need to was stupid. There must be quite
a few stupid people out there since Advanced Auto Parts sells several products for patching your muffler.

I spent about $25 on materials (of which I used about $5-10) to fix my muffler.

For me, this repair will be a success if the repair lasts a year or more. If it fails in the next few months then
you can call me names if you want to. Too many other more important things to do right now.

JRL - The Furnace Cement worked great! Feels very strong and I packed it hard into the crack. I hope it cures
sufficiently to hold for a while.

I used a wire brush, rust inhibitor, furnace cement, and high temp paint. Total time about 1.5 hours. Cost: ~ $10.
My muffler looks like new and the noise from the hole is gone. I took a before and after video. Never realized this
was generating so much noise. That said, my 850 is still quite noisy without the hole in the muffler.

[vjaneczko]

I took a before and after video.

Video? Video?! Show me video!

[1997volvo850]

I'll try to summarize what I did to repair my muffler.

Some other references on the web.

Here is an example of a complete muffler/tail pipe overhaul: nick.declario.com/cars/Legend/articles/exhaust-repair/exhaust-tutorial.pdf

This individual spent several hours repairing and refinishing his muffler and tail pipe. For me this was too expensive a task
(time-wise) given the cost of a new muffler.

Here is a fix on the other end of the spectrum: www.carinstructions.com/exhaust-and-muffler-pipe-repair/

My fix is somewhere in the middle. I want to reiterate that while some folks think this is a waste of time I feel that
experimenting with and learning about new materials is fun.

Again, this was a quick job intended to move the muffler replacement off a year or so. I did not follow normal guidelines
for doing this type of thing to save time. Spent a little over an hour on this.

Used a wire brush and rust inhibitor on the muffler and portions of the pipe. Warmed the muffler (ran engine) to speed
up the drying process. I applied two coats of rust inhibitor and I focused on the weak point of the muffler - the joint.
This is where the rust seems to be occurring.

Rust Inhibitor

Applied furnace cement. I'm new to this product but it seemed to work perfectly for this job. Handles up to 2700 degrees.
Consistency of clay. Forced it up into the cracks to create a key to hold it in. Appears to have enough strength to provide
a strong seal. I applied a very thick application of the furnace cement on the crack.

Furnace Cement

Rust inhibitor appeared to attack most of the rust. I used two or three coats. Then I decided to top coat for two
reasons: 1) provide protection from elements and slow the creation of new rust 2) make it easier for me to see if
rust is coming back.

Top Coat with High Temp Paint

Overall the project plan seems to have worked. The rust inhibitor is on my "always have on hand" list. This stuff
is great at slowing down the rust process. I spray it almost as much as I spray PB blaster. The furnace cement was
easy to work with. High temp paint had a nice broad tip and went on well and dried quickly.

If this fix lasts a year I will consider it a success. Remind me and I will post follow up pictures at 6 months and
a year.

Hope this helps.

[JRL]

I use black heat paint, you can't see the patch that way and I smooth out the outer edges a bit more
I'm not sure if you needed to shove it all the way in the hole (no comments here please)!! but it looks a solid as when I do it.
So far the ones I have done have lasted for over 10,000 miles and counting.......

If you think about it, why shouldn't this work?
This is a product to repair a home furnace, if it failed, someone could/would die from Co2 poison,
so you know it's had some serious product testing before it hit the market!
The heat in a (rear) muffler is FAR below furnace temps so if it is applied properly, it should last a long while.

Oh and one more thing if someone else does this.
You do not have to apply such a thick coating.
Use two thinner coats, (one right after the other, do not wait to let dry) that way you can blend the edges a bit better

[1997volvo850]

JRL: Thanks. I suppose I only deserve 7 of 10 stars on the JRL scale but remember I'm only an apprentice.

Your advice on the furnace cement was dead on. Some posters thought the muffler repair was crazy.
Just look what the guy did in the link I included. He spent several hours and even removed the muffler
to repair and refinish it.

Seems that leaving the seams rust unchecked is what does the muffler in. I suspect some minor
maintenance (rust inhibitor) will extend the life of the muffler a significant time.

For $10 and and about an hour and a half I'll let them call me names. I'm still amazed they guessed my
middle name. Ebenezer is just not a very common name these days.

I was worried about the furnace cement hardening and potentially falling off. I believe that forcing it
into the crack will make a natural key that will help the fix stay in place.

I also understand the gray paint shows the patch but I wanted to be able to see potential rust flare ups easier.

Sounds like your patch has held (though I don't know how extensive it was). It would be interesting to hear
the effects of time on your patch. I will be monitoring my repair and will report back on the effectiveness
of the patch materials over time. This is more interesting than just sticking on a new/used muffler.

Thanks.

[JRL]

One of the ones I did was minor, the second was almost as bad as yours was.
You did a GREAT job, I was nitpicking.
I think you're incorrect about checking, there's not much you could do, rust starts on the inside of an exhaust system.
However, I suppose that if an owner checks every year you could see where a rust hole/split is starting and with a small area this job would be even easier if you get to it early

[1997volvo850]

Thanks. I spent some extra time smoothing out the furnace cement knowing that I was
going to take pictures of it. I would have done more but I wanted to demonstrate the repair
in a very limited amount of time. I think the write-up has taken longer than the repair.

Preventative maintenance will save significant time down the road. I now understand. Now I know
to look under my car every so often. I hit quite a few other rusting items (hangers/fasteners)
while I was under the car. For the most part the rust proofing on the body is in excellent shape.

I can see where the main joint on my muffler seems prone to rust. Even though my muffler is still
fine except for the long hole along the seam I expect hitting the entire joint heavy with the rust inhibitor
will slow down the rust significantly. My 850:#1 todo list is too long to add another time intensive
item right now...actually need to do blower motor/resistor, work on keeping P0172 code away
(it's currently pending), and get the car inspected in near term...then need to switch to 850:#2
for some stuff (engine mount/PCV/PCT). I think kids are less work than my 850s.

Eventually the rust will win. But the lack of attention makes the replacement option occur much
sooner than necessary.

[1997volvo850]

I just wanted to update this thread after almost a year.

Much of the furnace cement finally fell off after nearly a year. I recently notice a slight increase
in noise.

Surprisingly, there was virtually no rust on the exterior of the muffler. I'm very impressed that
the rust inhibitor and high temp paint held up so well on the muffler.

The muffler still looked so good I saw no reason to replace it so...

I touched up a few spots with rust inhibitor and high temp paint (JRL - still have the silver paint - but I'll get black when
I run out! )

I reapplied a fresh layer of furnace cement and sealed it with paint so I'm good for another 20K miles. Took about
15 minutes this time...I should have taken before/after pictures...I'll try to remember to take a picture at the
next touch up in 20k miles. That's unless she rusts out from the inside first...

I'm most impressed with how the rust inhibitor and high temp paint held up. Aside from the missing furnace cement
the muffler looked almost as good as the picture taken immediately after I did it the first time.

Ebenezer

[urbex]

Stupid? I've always thought spending $400-500 dollars when I didn't need to was stupid. There must be quite
a few stupid people out there since Advanced Auto Parts sells several products for patching your muffler.

Why yes, there are quite a few stupid people out there! Just because a store sells something doesn't mean it works - it just means that they're expecting enough people to _buy_ it to make it profitable to have on the store shelves. Pulstar spark plugs come to mind, as do all those radiator cleaner/flush products out there. Oh, and Slick 50/Zmax/all those other oil additives (I did rather enjoy the Zmax infomercial where they claimed to be drive a car all around town with absolutely no oil in the crankcase, because the thin film left behind by the Zmax was plenty enough to protect the engine...yet they never explained how the hydraulic lifters were operating with zero oil pressure......)

There are also quite a few people who seem to be more willing to spend far more money to "repair" a part, repeatedly, than it would cost just to replace it once and be done with it.