I have new flowmasters that are mounted at an angle so that alot of water could collect in them. I have seen suggestions here to drill a small (less than 1/8 inch) hole at the low spot to let it drain. Good idea or bad ??? would this cause accelerated rust to occur at the hole ??? 15 min. drive to work probably doesn't dry em out ! ?

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Gotta have a Chevy !In Durham N.C.
Why is there never enough time or money to do it right the first time, but ALWAYS enough to do it over?
Make it look the way you like it, forget what the other guys say!

I've seen that in some previous vehicles I've purchased new. An 80 Z-28 had a tiny hole in the lower rear of each resonator. My wifes 92 Toyota Forerunner has the rear of the muffler drilled as well as my 90 Accord. If the factory takes the time to do it, there must be something to the theory.

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Dave MacGregor
Vancouver,Canada

Team Chevelle #27
70 Malibu 454

283
my dads 63 riv had a weep hole in the rear of the muffler,try it,should work. 67RAT member #199

I wouldn't worry about it. If rust occurs it'll result in... guess what? a hole in your muffler. Besides you'll hate the small exhaust leak sound.

Drill the hole you will never hear the small leak.With out it it will rust out for sure with that type of short trips...FRED

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DON'T drill the hole. FlowMasters are quality mufflers with plenty of metal (galvanized or aluminized). They should last year and years and years. Don't sweat it.

Bob

Not all Flowmasters are galvanized or aluminized!

I drilled a small hole in both of mine (about 9 months ago) and there hasn't been any problem.

My thinking is that if the water "promptly" drains out, it's better than sitting there (and rusting).

I live in L.A., and I still don't clearly understand why it seems to build a lot of condensation in the exhaust system!!

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Wes. Vann
Technical Reference & Wagons sections
Gold Member #5

Drill the hoel so the water will drain, you wont hear the leak because the pressure isnt that high there, so the exhaust doesnt want out that bad.

No matter where you live, burning gasoline,breaks it down into CO CO2 AND H2O(as well as others) For every gallon of gasoline burned, about a gallon of water is released out the tail pipe. Now when this hot steamy water vapor enters your cold exhaust system, condensation occurs, which is where your water in the muffler comes from. As you drive and get the exhaust up to temperature, the condensation, doesnt take place until the exhaust is already out of the tailpipe, so you dont see it when it warms up or is warm outside.

HTH

283
Why don't you drill a hole in one and not the other then let us know which one lasted longer http://www.chevelles.com/forum/smile.gif good luck with your flowmasters (I love mine)


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#23 GOLD
San Diego,Ca.
www.chevelles.com/showroom/70EC1.jpg (http://www.chevelles.com/showroom/70EC1.jpg)

Hey !! great idea, I have Flowmasters on my 77 Dodge 440 pull truck and it spits water all over when its started [untill warmed up] I am going to drill mine this weekend ,, Flow Masters are aluminumised but ONLY on the outside ,, I work on farm tractors for a living and its common to see bleed holes in mufflers and nope you cant hear a thing from holes

Just went out and looked at my Flowmasters ,, I'll be dammed they already have small holes in them ! they are 3 chamber,, only problem is the holes are faceing up ,, DOE !! oh well it was the only possition installer could get them to fit ,, ill still drill small hole in bottom of each ;)

When I was 9yr old I wish Dads car had weep holes in the mufflers! One Sat. evening Dad told me to wash the car. So I did. Well I did what a lot of kids do and that was play around while washing a car. Neeedless to say, I was amazed at how much water the exaust pipes could hold.... Well the next morning as we were getting ready to go to church, all dressed up & stuff, Mom walked right behind the car as Dad fired up the family truckster ..... you can't even imagine how tired my legs were from running and not from my dad either. Living on a mini farm always had some little suprise, but this day was the worst! As Mom chased me out the gate, I jumped clear of the fresh cowpie...and mom, well she never did have the jumping abilities that I had. When Dad finally stopped me and calmed things down, I knew I would live 'cuz the ass chewing I got was unlike any other I'd experianced, he had a grin on his face http://www.chevelles.com/forum/smile.gif Dad & I had the roughest summer that year.

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Lowered '67 Elcamino
ZZ430 eng / 4L60E trans
"Canyon Carver"

Cardiac; That story is GREAT! I'm glad that you lived to tell it.

Catman; All I can say about all Flowmasters being aluminized, is that mine are NOT! The new ones may be.

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Wes. Vann
Technical Reference & Wagons sections
Gold Member #5

Thanks Cardiac. I haven't laughed this hard in a long time!

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69 Malibu Sport Coupe
Team Chevelle 461
ACES 3119

Drill the holes.

Without them, salts and other chemicals that are present in the combustion created moisture, and ones made from the conversion of the moisture as the mufflers cool, will eventually disrupt the coating, causing rotting and metals erosion.

Although the mufflers do heat up enough to remove most moisture from them, when the engine is shut down and as the muffler(s) cool, there comes a point where cooler, moisture laden air is pulled into the cool muffler, and accumulates, then the air and moisture separate. The moisture is retained until the next running event.

Drill the holes.

The cross mounted Flowmaster on my buddies 70 RS Camaro came with a hole in it.

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Bob (Creedmoor,N.C.)
65 Vette B&M Blown, Richmond 5-speed
68 Malibu B&M Blown, Turbo 350 10" converter

My 1999 GMC Sierra Z71 has a very small hole about 1/8th inch. I don't hear a thing but I sure see lot of water dripping out as it warms up.

The ouside might be SS or galvanized but is the inside? I saw a SS system at the parts stores years back that was solid but they cut open the muffler and it was rusted out. Rust will kill the muffler very fast. Had a 1987 Pontiac and the shop put new exhaust system on it many years ago. Asked me should they drill a weep hole, I said hell no. It lasted about a year and rusted from the inside out and it was a lifetime muffler. Next one got the drill hole and it lasted about 3 years.

The hole should be on the rear face of the muffler, the outlet end. Don't drill in the body!