Muffler water drain holes

[dom14]

Hi Guys,

I'm beginning to think that I might have created a problem, rather than solving a problem,
when I repaired my leaking muffler box couple of years ago with welding.

Basically, the muffler was leaking and making that annoying noise.
So, I went under it and as it shows in the picture, I spotted the problem areas.

The only thing I didn't know back then was that there's a thing called "Muffler weep holes"
So, there was a definite rust deterioration on the side wall as in the picture, which I welded and repaired,
which I believe I did the right thing at the right time.

Then at the bottom I noticed four holes as well. At least three of the holes appeared to be leaking exhaust gas,
'cos I could see the soot around the holes. So, I thought I should repair them as well.
Even though they appear to be holes, I couldn't actually see a hole into the inside of the muffler.
It was more like rusted little circle, even after wire brushing it.
Any way, I filled it with mig weld and cleaned and sprayed some heat resistant paint to make it look good.
It's been going ok for almost two years, until few months back I just had to touch up the bottom ones again.

Now, I got to know about the "weep holes" to drain the exhaust moisture that get trapped in the muffler, I began
to think that I must have blocked the weep holes.

Muffler is still going fine as far as I can see. I've attached a video as well of the exhaust, showing little bit of water dripping
form the end of it, while the engine was running(this morning). The water was still dripping after 5-10 minutes of engine running,
though today was a very very cold morning(zero degrees)

https://www.youtube.com/watch?v=1h66gPBF_Hg

Now, I'm bit worried whether I've blocked the "weep holes" and created a problem by causing the muffler to gather water and
cause corrosion, blockage and eventual blow up.

What should I do?!

Should I drill a small hole in one of the blocked hole spots to allow the water weeping thing to happen again?

Any advice would be great.

Thanx

[Bloodyaussie]

Time for a new muffler.... that thing would be stuffed inside.

[dom14]

Time for a new muffler.... that thing would be stuffed inside.

It appears to be going ok. I hear no noise or rattling, etc.

I blew the inside with compressed air last year.
I couldn't feel a resistance. No crap came from inside either.

Is there a backyard method to test a dying muffler?

I reckon I should go back to my vacuum tester?
I wouldn't mind keeping it going for a while, if that's doable.

Thanx

[Bloodyaussie]

Start the car and get someone to bloke the end of the exhaust with a rag while you have a listen for any leaks around the muffler..

[Cuppa]

My opinion fwiw...... I’d be inclined to continue using it as is until it rusts out ....... & then get a new one. The fact that it rusted 2 years ago suggests it was on it’s way out, & you have managed to keep it going. Any extra time you get on it now is a bonus, so not really worth stuffing around with it now.

[dom14]

Start the car and get someone to bloke the end of the exhaust with a rag while you have a listen for any leaks around the muffler..

Hi mate,
There're no leaks at the moment. I've fixed all the exhaust leaks. There were minor ones from flanges.
But, not so minor, 'cos my misfiring and backfiring problems don't seem to appear after I fixed all the very small exhaust leaks
(one in manifold flange gasket, another in the flange gasket after that).
I also blocked the vent on the top of the TVV(Thermal Vacuum Valve) with sticky tape.
If you've followed my previous thread, you may remember I had the TVV issue with it's venting from the top of the valve.
It's not suppose to do that I reckon. So, I sticky taped it.
I'm not 100% sure whether my misfiring was fixed by fixing those exhaust leaks or 'fixing' the TVV.
I'll start another thread to discuss that.
I reckon I'm just gonna do the vacuum test at the intake again and see if it shows any exhaust blockage.
But, the compressed air test I did(last year in December though) was a good one, 'cos I set it up in a way to let go a fair
bit of compressed air into the muffler. It didn't blow any crap, nor it showed any resistance.
That's why I like to keep this muffler going for a while. :D
A new one is usually more expensive than extractors themselves, so I reckon I should try to get as much life as possible from
this old exhaust.
As a matter of fact, two years ago when I repaired the leaks, I did a 'good' job with it by painting it to look like a brand new one. :cool:

[dom14]

My opinion fwiw...... I’d be inclined to continue using it as is until it rusts out ....... & then get a new one. The fact that it rusted 2 years ago suggests it was on it’s way out, & you have managed to keep it going. Any extra time you get on it now is a bonus, so not really worth stuffing around with it now.

Hey Cuppa,
Should I open the hole by drilling it, that was apparently meant as a water weep hole?
At least one hole, just to extend it's life bit longer?
BTW, aftermarket mufflers(many of them) don't seem to have weep holes.
Why is that? I'm wondering.
Thanx

[Throbbinhood]

Never seen weep holes on any of my mufflers. Got a nice little one though where a rock decided to poke it's head in and take a look around.

[dom14]

Never seen weep holes on any of my mufflers. Got a nice little one though where a rock decided to poke it's head in and take a look around.

i would fill the hole with either weld or some of the heat resistant putty stuff(Maniseal, etc). Small hole can turn into a big hole in no time, as in the case of my muffler.
I was able to repair it with fair bit of patience and a combination of mig and arc welding(yes, I used an arc welder as well, don't ask me how I manage that. :D).
It's a real PITA to weld thin sheet metal used in mufflers, even with a mig welder. It's pretty easy to blow a bigger hole, rather than filling the existing leak hole. :D
IMO, the ideal welder to repair mufflers is TIG. But, TIG doesn't work with rusty surfaces, so needs heaps of wirebrushing and removing all the rust contaminants first.
I haven't done that yet. It's easy to write about it, rather than doing it. :D

[Cuppa]

Hey Cuppa,
Should I open the hole by drilling it, that was apparently meant as a water weep hole?
At least one hole, just to extend it's life bit longer?
BTW, aftermarket mufflers(many of them) don't seem to have weep holes.
Why is that? I'm wondering.
Thanx

I’m no expert, but I also can’t recall having any weep holes in a car muffler before, so I’d be inclined to stick with the instinct you had when you welded them up. I have had a weep hole in a mototorcycle exhaust before, a Moto Guzzi le Mans with aftermarket Italian pipes, but from memory it was at the lowest point of the pipe, not in the muffler, & then only because the mufflers were upswept. They still rusted out, but the pommie habit of salting the roads, in combination with crap Italian chrome probably had a lot to do with that.

[dom14]

Come to think of it, muffler is a box that usually sits bellow the exhaust pipe line. So, water can gather inside I reckon.
But, unless there's head gasket issue, once it's warmed up, the water should simply evaporate with the heat out of the exhaust end pipe.
Then again, most of the short runs we do, don't allow the muffler to get hot enough I reckon.
So, the water can gather inside.
What puzzles me though, it can't be that easy to create a weep hole into the muffler internal compartments without creating a exhaust soot
leak through the same hole. So, to me, it's kinda defeats the purpose.
My muffler has been going ok regardless of my welding filling of the "weep holes".
So, I reckon I did the right thing.
Yeah, it makes sense bike mufflers having weep holes 'cos they are upswept.
Then again, most car exhausts are down swept, and that's probably the reason I rarely see weep holes in car mufflers.

As Cuppa mentioned, it's look like I'm getting a good deal with this muffler anyway.
After repairing the muffler rust spotted leaks two years ago, it's still going. So, that's a bonus that I can't whinge about.

I reckon I should do the vacuum tester test of the intake straightaway and confirm there's no exhaust blockage or excess pressure.

Unless this particular muffler has a design to have that weep hole in order the balance the exhaust pressure as well, I should leave it alone.

Yeah, I think I'm gonna leave the muffler alone and give it another heat resistant silver paint spray to make it look new. :D

[moonie]

If your car is a turbo diesal just remove muffler altogether and put a hot dog whitch has no restitions or replace with pipe same size i took my mufflers off my GU 4.2 turbo spools up better an engine runs better i know of other people who have done the same and get better fuel as well//hope this helps.

[Robo]

If your car is a turbo diesal just remove muffler altogether and put a hot dog whitch has no restitions or replace with pipe same size i took my mufflers off my GU 4.2 turbo spools up better an engine runs better i know of other people who have done the same and get better fuel as well//hope this helps.

So how loud is it now without the muffler? near legal or not at all?.

[threedogs]

Start saving for a new free flowing muffler/hotdog whatever you want to call it.
Pointless trying to repair it unless funds are tight.
I good exhaust is better on your tune and fuel figures to.

[Robo]

The bits you touched up in the middle were spot construction welds.
You simply repaired them.
only holes are in/out either end etc for exh gasses.
otherwise exh fumes can make their way into cabin through the floor somewhere etc.
And not legal and certainly dangerous to ya health.
cheers

[Chimo]

I am also not an expert but I have weep holes in my Celica (1973) muffler and as result the muffler has not rusted out (muffler is at least 18 yrs old but honestly I cannot remember) as the water can drip out rather turn into concentrated acid over time and rust out the muffler.

On our Ford, as replace we mufflers all be it very infrequently, I always drill an 1/8 th or a bit bigger hole in the middle of the muffler down low as shown in one of the pics above. I feel sure its a good thing and worth doing, I sure would not block one up.

When we fitted the turbo to the GQ TD 4.2 Patrol we did not fit a muffler, just a muffler looking thing with a pipe straight thru as the turbo acts as a muffler and it was not needed. No hole in that one!!!

Cheers
Chimo

[Woof]

Just checked my new exhaust system that is sitting in my dining room and the muffler has no holes in it at all

[mudnut]

Just putting it out there
but I think that any vehicle
operated in Vic on
a Fire Ban day is required
to have 100% of
the exhaust gases to
exit the system via the
tail pipe.
If you have holes in the
muffler it would be unroadworthy
wouldn't it?

[Chimo]

Leaving a road while driving an unleaded petrol car should be illegal. Certainly stopping in a stubble paddock when in an unleaded petrol car can be exciting especially as the smell intensifies and should be illegal too. Maybe having holes so the moisture can drip out could counter the heat a very little too !

C
C

[Robo]

Leaving a road while driving an unleaded petrol car should be illegal. Certainly stopping in a stubble paddock when in an unleaded petrol car can be exciting especially as the smell intensifies and should be illegal too. Maybe having holes so the moisture can drip out could counter the heat a very little too !

C
C

So why then, apart from the obvious, are modern diesels fitted with catalytic converters!

[dom14]

Just putting it out there
but I think that any vehicle
operated in Vic on
a Fire Ban day is required
to have 100% of
the exhaust gases to
exit the system via the
tail pipe.
If you have holes in the
muffler it would be unroadworthy
wouldn't it?

I don't think weep holes are illegal. Many stock muffler designs seem to have it.

[dom14]

Just checked my new exhaust system that is sitting in my dining room and the muffler has no holes in it at all

You can't eat without having the new muffler next to you?! :D

[dom14]

Start saving for a new free flowing muffler/hotdog whatever you want to call it.
Pointless trying to repair it unless funds are tight.
I good exhaust is better on your tune and fuel figures to.

Yes. I learnt it the hard way to find out few of my engine hiccup issues were partially related to exhaust leaks from flanges near the exhaust manifold.

[dom14]

Start saving for a new free flowing muffler/hotdog whatever you want to call it.
Pointless trying to repair it unless funds are tight.
I good exhaust is better on your tune and fuel figures to.

Are they noisier than the stock ones?

[dom14]

If your car is a turbo diesal just remove muffler altogether and put a hot dog whitch has no restitions or replace with pipe same size i took my mufflers off my GU 4.2 turbo spools up better an engine runs better i know of other people who have done the same and get better fuel as well//hope this helps.

Wouldn't that cause excess noise? How do you address the noise issue?

[Chimo]

Turbo acts like a muffler.

Tested this when we fitted the turbo by starting the GQ with the turbo bolted on but with no exhaust pipe attached. I didn't believe it either until we did it.

[dom14]

Turbo acts like a muffler.

Tested this when we fitted the turbo by starting the GQ with the turbo bolted on but with no exhaust pipe attached. I didn't believe it either until we did it.

No kidding! I'll need to do some homework on that. I'll go turbo eventually, but first need to go EFI.

[Robo]

Turbo breaks up sound waves, result is lots less noise.

[dom14]

Turbo breaks up sound waves, result is lots less noise.

Yeah, so the excess noise I hear from lot of turbo charged cars is from blokes messing with the exhaust to make extra noise??!!

[Robo]

there's legal and nearly, probably not legal noise your quoting.
more likely cheap fleabay and then just cheap what ever

I parted with a GTR skyline last year and trust me,
If I took the turbo's off it and left the same 80mm pipes with large cannon etc It would of been 3 x as loud.
at 4ooo rpm it was surprisingly quite, you could actually tell when the turbo's were cutting in to break up the noise.
don't ask what it was like at 8000rpm, different horses for courses.
(short answer fun fun fun 2x garretts & huge induction noise also).
sob sob.