Should I drill holes in mufflers? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

KEH · 01-13-2004, 12:09 PM

The shop that installed my exhaust mounted my mufflers in the vertical position. I don't know if this is good or bad, but a guy from Midas saw it and said it was stupid. He said they would build condensation and rust out. He told me to drill small drain holes in the low points of the mufflers.

I guess it sounds logical to me. What do you guys think?

PR454SS · 01-13-2004, 12:14 PM

can you turn them in anyway? sounds like they put the wrong muffler on your truck, or just making sure they get repeat business

If the truck isn't used with a camper or anything so you don't worry about fumes I guess it would be okto drill small holes, just sounds like adding to the problem to me.

Primed67 · 01-13-2004, 12:15 PM

I have had mufflers mounted like that and never had a problem. I had to mount mine like that because of space and clearance issues. If you drill holes in the mufflers your exhaust will be louder because the exhaust is escaping out the holes you drilled.

**N2TRUX** · 01-13-2004, 01:22 PM

Most stock mufflers have a small 1/8" hole drilled at the lowest point at one end. It won't make it any louder, but it will be another spot that it will start to rust...

junkyardjohn · 01-13-2004, 01:29 PM

Most stock mufflers have a small 1/8" hole drilled at the lowest point at one end. It won't make it any louder, but it will be another spot that it will start to rust...
I THINK I'LL HAVE TO RAISE THE B.S. FLAG ON THIS ONE

NO MUFFLERS THAT I HAVE EVER OWNED HAVE HAD ANY HOLES DRILLED IN THEM TO LET MOISTURE ESCAPE. SOUNDS KINDA LIKE DRILLING HOLES IN THE BOTTOM OF YOUR BOAT TO LET THE WATER OUT.

JOHN

cdowns · 01-13-2004, 01:52 PM

OK I'M GOING OUT TO DRILL HOLES IN MY BOAT GOOD IDEA

*67Fleetsidedream* · 01-13-2004, 02:12 PM

If you drive more than 35 miles a day don't worry about it. Most of all mufflers have a aluminized coating on the inside and the outside to help them resist rust. Driving more than 35 miles a day will heat the muffler up enough to evaporate the condensation build up.

Rooster's 67 · 01-13-2004, 02:20 PM

ok...ok.....ok factory mufflers and alot of aftermarket replacement(stock style) have a small 1/8 inch or so hole at the lowest point in the muffler. to drain condensation out of the muffler. If you drill a small(1/8 inch) hole at the lowest point it will drain condenstion but at the point you drill the edge of the hole will have the aluminization removed and will allow that hole to rust. And true if you drive enough miles at one drive cycle it will help to evap the condensation in the muffler, and the oils and the lubes. short trips are hard on vehicles and will put them into the severe use catagory on most any manufacturers maintence schedules.

Drill if you are worried dont if your not.
your not goung to cause the world to fall off of its axis either way.

Rooster's 67 · 01-13-2004, 02:24 PM

junkyardjohn........I guarantee that the 84 you own had moisture release holes in the mufflers from the factory

and most boats do have a hole at the lowest point to let water out,,,,,but MOST people plug them before floating their boat.

67chevemall · 01-13-2004, 03:30 PM

Sounds like advise for the dumb a55 ricers that spend $1000's on a lound exhaust for a civic!
If they were smart enough they would just drill a flippen holes in the stock exaust or muffler!

Don't drill holes man re do it!

Grim Reaper · 01-13-2004, 03:39 PM

Quote:

Originally posted by KEH
The shop that installed my exhaust mounted my mufflers in the vertical position. I don't know if this is good or bad, but a guy from Midas saw it and said it was stupid. He said they would build condensation and rust out. He told me to drill small drain holes in the low points of the mufflers.

I guess it sounds logical to me. What do you guys think?

And they are not going to condinsate laying flat? I have as yet to see a muffler that doesn't have some sort of lip that is going to preven any water from colecting not to mention most mufflers are mounted before the axle and have to route the pipe up over that.

If you have more then a teaspoon of water collect in your muffler when you shut it down you got a lot bigger problems then condisation. You got a blown head gasket or your truck is in the lake.

Mufflers need some sort of volume to do their job. THe reason they are flat is to alow them to tuck up to the floor of the vehicle. It doesn't really matter what way they mount as far as performance.

As for the condinsation that they do produce. That 500 degree air moving through it will change it to vapor and move it out just like the heat in the crank case does for the condisation in there.

67chevemall · 01-13-2004, 04:47 PM

Grim Knows!

Russell · 01-13-2004, 04:56 PM

Quote:

Originally posted by Rooster's 67
junkyardjohn........I guarantee that the 84 you own had moisture release holes in the mufflers from the factory

and most boats do have a hole at the lowest point to let water out,,,,,but MOST people plug them before floating their boat.

"MOST" people, hehehe, that was an interesting boat launch....

stingray72 · 01-13-2004, 05:02 PM

Quote:

Originally posted by Russell

"MOST" people, hehehe, that was an interesting boat launch....

Don't laugh... I did it.. Got 1/2 way across the lake when I noticed the boat wasn't planing to well. Let off the gas and got drilled by 50 gallons of water. Lucky for me my boat is a Direct drive and the plug is installed under the engine right behind the drivers seat. I got a good bath but got the plug in before the boat went under. Bilge pump got a good workout

BTW... I laugh at myself for this one to this day

Maximum Overdrive · 01-13-2004, 06:36 PM

Quote:

Originally posted by Rooster's 67
ok...ok.....ok factory mufflers and alot of aftermarket replacement(stock style) have a small 1/8 inch or so hole at the lowest point in the muffler. to drain condensation out of the muffler.

Mine has holes but I wouldnt say they are drain holes.

Longhorn Man · 01-14-2004, 12:30 AM

I have seen plenty of mufflers with the aformentioned drain holes. Both OEm and replacement style. I have never seen them cause any noise either. Not a single one.
If you decide to poke holes in your mufflers, spray a little high temp header paint in the hole. 1200 degree paint should hold up way back there...even 500 degrees amy be a bit high of an estimate.

Hooter · 01-14-2004, 12:37 AM

I dont think it is gonna make your mufflers last any longer, mayvbe a year or two more, they'll rust out, eventually, especially if you drive it in the winter, of course the best way is to go stainless steel but it is pricey, unless you work at a mill and get it all for free

Blue Beard · 01-14-2004, 12:49 AM

my 2000 has a hole in it ........weeps water (condensation)

Rod · 01-14-2004, 01:44 AM

Hmmm.. well up here if you want lifetime warranty on your exhaust muffler they center punch a hole in it at the lowest point at rear.. one year warranty = no hole... same muffler either way. Thats what I noticed.

**N2TRUX** · 01-14-2004, 02:18 AM

Quote:

Originally posted by junkyardjohn
NO MUFFLERS THAT I HAVE EVER OWNED HAVE HAD ANY HOLES DRILLED IN THEM TO LET MOISTURE ESCAPE. ....

OK, Ill be specific then. NO the holes aren't "drilled" in them, they are punched or stamped in them.

Do us favor and go look at a few stock mufflers before you call my response bullsh!t. Do us another favor and turn YOUR CAP LOCK OFF

chevymad · 01-14-2004, 02:24 AM

Anybody ever hear a ford exploder with the stock steel muffler? Drain holes right in the middle. After it rusts a bit they tend to make a whistling noise. I've had many people come in wondering whats wrong with their ford.

BUXMAN66 · 01-14-2004, 03:46 AM

it's a ford ding-dangit!! god this is a funny thread!!!

junkyardjohn · 01-14-2004, 07:59 AM

Quote:

Originally posted by N2TRUX
OK, Ill be specific then. NO the holes aren't "drilled" in them, they are punched or stamped in them.

Do us favor and go look at a few stock mufflers before you call my response bullsh!t. Do us another favor and turn YOUR CAP LOCK OFF

NUTUTRUX. HMMMMM -- I CRAWLED UNDER ALL 8 OF MY TRUCKS..... & NOT A SINGLE DRAIN HOLE TO BE FOUND IN ANY OF THEM (& MOST HAVE 2 MUFFLERS) BUT MY NEWEST TRUCK IS 22 YEARS OLD, & THEY'RE ALL CHEVYs OR GMCs. I ALSO HAVE 4 BRAND NEW IN THE BOX FLOWMASTER 40s SITTING HERE WITHOUT ANY DRAIN HOLES. ALSO A PAIR OF HOOKER AERO CHAMBERS & NO HOLES. MAYBE IT'S A RECENT THING, OR JUST ON DODGES & FORDS??
AS FAR AS ME TYPING IN ALL CAPS (NOT THAT I FEEL THE NEED TO EXPLAIN MYSELF TO YOU) I'M HANDICAPPED & ONLY TYPE WITH ONE FINGER ON MY LEFT HAND, & FIND IT A REAL PITA TO SWITCH FROM LOWER CASE TO UPPER CASE ALL THE TIME. IF IT BOTHERS YOU TERRIBLY..... PLEASE PUT ME ON YOUR IGNORE LIST(IT'S UNDER USER CP) & MY POSTS OR REPLYS WONT SHOW UP TO YOU.
DRIILING HOLES IN YOUR MUFFLER (& BY ALL MEANS DO IT) SEEMS LIKE TAKING A BATH WITH YOUR SOCKS ON TO ME. OUT HERE EXHAUST SYSTEMS LAST 8 - 10 YEARS AS COMPARED TO 2 YEARS WHEN I LIVED BACK IN MICHIGAN.

Huck · 01-14-2004, 11:48 AM

And to think I spend hours trying to seal up holes in my exhaust with a welder---only to find out I should be making holes!? Actually I have done the hole thing and am not sure that it really makes a big difference as mufflers are internally designed to muffle---and are NOT designed to drain condensation to any pre determined spot so you will probably be doing a superficial thing with drilling a hole for the lowest point. Condensation will still collect water within the baffles that gravity will not drain.
My personal preference is to leave the SOB alone as after a while I kind of want a change of tone and another muffler anway. AND I don't want to hear a cherp,peep,sush,pop etc. from the exhaust that I caused. I got enough from my crappy welding already!!

**N2TRUX** · 01-14-2004, 11:54 AM

Naaa, your post don't really bother me with the cap lock thing. At least now I know why. Normally I find your responses very informative and polite. That's why I was surprised when you got on my reply as bullsh!t that way.

I do have a lot of late model stuff, but I can vouch for at least one older GM vehicle haveing the hole in a stock muffler. The first time I saw the drain hole in question was on my 84 Z-28. It had one in the factory muffler and it always puked black carbon crap across the muffler.

I know my 95 and 97 Silverado had the same hole in itheir muffler too...

BTW- I'm not handicapped and I only use two fingers to type

01-13-2004, 12:09 PM	#1
KEH Better late than never Join Date: Dec 2001 Location: Columbus, IN Posts: 324	Should I drill holes in mufflers? The shop that installed my exhaust mounted my mufflers in the vertical position. I don't know if this is good or bad, but a guy from Midas saw it and said it was stupid. He said they would build condensation and rust out. He told me to drill small drain holes in the low points of the mufflers. I guess it sounds logical to me. What do you guys think? __________________ 1970 C/10 SWB Stepside

01-13-2004, 12:14 PM	#2
PR454SS Registered User Join Date: Aug 2003 Location: Louisville, TN Posts: 338	can you turn them in anyway? sounds like they put the wrong muffler on your truck, or just making sure they get repeat business If the truck isn't used with a camper or anything so you don't worry about fumes I guess it would be okto drill small holes, just sounds like adding to the problem to me. __________________ PR Too many projects, not enough time! 72SWB 350/350TH, 3500stall,525 lift cam 3:73 posi. Sold! 69LWB Flatbed 350/Super T-10, ported/polished 481 heads, 480 lift cam. 78SWB 468/400TH, ported/polished Alum. heads, 3:42 posi, 3000 stall on 17x8 and 18x9.5's 77 Jeep CJ-5 304V8 fiberglass body on 36" Ground Hawgs

01-13-2004, 12:15 PM	#3
Primed67 Registered User Join Date: Sep 2003 Location: Tyler Posts: 575	I have had mufflers mounted like that and never had a problem. I had to mount mine like that because of space and clearance issues. If you drill holes in the mufflers your exhaust will be louder because the exhaust is escaping out the holes you drilled. __________________ 1969 Chevrolet SWB Stepside 1959 Chevrolet apache * Sold 1967 Prostreet Chevy SWB Fleetside *Sold 2014 1/2 ton Crew Cab Chevrolet 4x4

01-13-2004, 01:22 PM	#4
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,023	Most stock mufflers have a small 1/8" hole drilled at the lowest point at one end. It won't make it any louder, but it will be another spot that it will start to rust... __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

01-13-2004, 01:29 PM	#5
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,427	Most stock mufflers have a small 1/8" hole drilled at the lowest point at one end. It won't make it any louder, but it will be another spot that it will start to rust... I THINK I'LL HAVE TO RAISE THE B.S. FLAG ON THIS ONE NO MUFFLERS THAT I HAVE EVER OWNED HAVE HAD ANY HOLES DRILLED IN THEM TO LET MOISTURE ESCAPE. SOUNDS KINDA LIKE DRILLING HOLES IN THE BOTTOM OF YOUR BOAT TO LET THE WATER OUT. JOHN __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST Last edited by junkyardjohn; 01-13-2004 at 01:33 PM.

01-13-2004, 01:52 PM	#6
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	OK I'M GOING OUT TO DRILL HOLES IN MY BOAT GOOD IDEA __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

01-13-2004, 02:12 PM	#7
67Fleetsidedream Wiseass secured himself a BAN Join Date: Nov 2000 Location: MOON!!! Posts: 2,282	If you drive more than 35 miles a day don't worry about it. Most of all mufflers have a aluminized coating on the inside and the outside to help them resist rust. Driving more than 35 miles a day will heat the muffler up enough to evaporate the condensation build up.

01-13-2004, 02:20 PM	#8
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	ok...ok.....ok factory mufflers and alot of aftermarket replacement(stock style) have a small 1/8 inch or so hole at the lowest point in the muffler. to drain condensation out of the muffler. If you drill a small(1/8 inch) hole at the lowest point it will drain condenstion but at the point you drill the edge of the hole will have the aluminization removed and will allow that hole to rust. And true if you drive enough miles at one drive cycle it will help to evap the condensation in the muffler, and the oils and the lubes. short trips are hard on vehicles and will put them into the severe use catagory on most any manufacturers maintence schedules. Drill if you are worried dont if your not. your not goung to cause the world to fall off of its axis either way. __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

01-13-2004, 02:24 PM	#9
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	junkyardjohn........I guarantee that the 84 you own had moisture release holes in the mufflers from the factory and most boats do have a hole at the lowest point to let water out,,,,,but MOST people plug them before floating their boat. __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

01-13-2004, 03:30 PM	#10
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Sounds like advise for the dumb a55 ricers that spend $1000's on a lound exhaust for a civic! If they were smart enough they would just drill a flippen holes in the stock exaust or muffler! Don't drill holes man re do it! __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

01-13-2004, 04:47 PM	#12
67chevemall Registered User Join Date: Apr 2003 Location: NB Posts: 3,367	Grim Knows! __________________ 1968 Chevy C10 307 3ott fleetside 1967 Chevy C/10 V8, 3spd, fleetside lwb.Sold 1967 Chev C/10 step, 383, M21. SOLD

01-14-2004, 12:30 AM	#16
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	I have seen plenty of mufflers with the aformentioned drain holes. Both OEm and replacement style. I have never seen them cause any noise either. Not a single one. If you decide to poke holes in your mufflers, spray a little high temp header paint in the hole. 1200 degree paint should hold up way back there...even 500 degrees amy be a bit high of an estimate.

01-14-2004, 12:37 AM	#17
Hooter My other Love Join Date: Aug 2001 Location: Castlegar B.C. Canada Posts: 4,085	I dont think it is gonna make your mufflers last any longer, mayvbe a year or two more, they'll rust out, eventually, especially if you drive it in the winter, of course the best way is to go stainless steel but it is pricey, unless you work at a mill and get it all for free __________________ Castlegar B.C.The great white North (Canada Eh!) Hooter_5@hotmail.com First generation Monte Carlo club pictures of my life

01-14-2004, 12:49 AM	#18
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	my 2000 has a hole in it ........weeps water (condensation) __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-14-2004, 01:44 AM	#19
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Hmmm.. well up here if you want lifetime warranty on your exhaust muffler they center punch a hole in it at the lowest point at rear.. one year warranty = no hole... same muffler either way. Thats what I noticed. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.



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01-14-2004, 02:24 AM	#21
chevymad Registered User Join Date: Jan 2001 Location: skamokawa, WA, USA Posts: 527	Anybody ever hear a ford exploder with the stock steel muffler? Drain holes right in the middle. After it rusts a bit they tend to make a whistling noise. I've had many people come in wondering whats wrong with their ford. __________________ 70 C10 long fleet, 355/200 4r, 6 lug disc conversion, 3" drop 70 gmc changed to 67/8 chevy, 454 with voodoo cam, th400, all 74 running gear.. in progress

01-14-2004, 03:46 AM	#22
BUXMAN66 go bucks! Join Date: Jan 2002 Location: MIAMISBURG OHIO USA Posts: 803	it's a ford ding-dangit!! god this is a funny thread!!! __________________ '68 swb 1/2t 350/350th '86 lngbd 3/4 TON parts getter '49 gmc 1/2 t 5 window 350/350th '96 gmc sonoma sle ext-cab. hey it's a 4cyl. 5 spd and good on gas y'know?

01-14-2004, 11:48 AM	#24
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,269	And to think I spend hours trying to seal up holes in my exhaust with a welder---only to find out I should be making holes!? Actually I have done the hole thing and am not sure that it really makes a big difference as mufflers are internally designed to muffle---and are NOT designed to drain condensation to any pre determined spot so you will probably be doing a superficial thing with drilling a hole for the lowest point. Condensation will still collect water within the baffles that gravity will not drain. My personal preference is to leave the SOB alone as after a while I kind of want a change of tone and another muffler anway. AND I don't want to hear a cherp,peep,sush,pop etc. from the exhaust that I caused. I got enough from my crappy welding already!!

01-14-2004, 11:54 AM	#25
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,023	Naaa, your post don't really bother me with the cap lock thing. At least now I know why. Normally I find your responses very informative and polite. That's why I was surprised when you got on my reply as bullsh!t that way. I do have a lot of late model stuff, but I can vouch for at least one older GM vehicle haveing the hole in a stock muffler. The first time I saw the drain hole in question was on my 84 Z-28. It had one in the factory muffler and it always puked black carbon crap across the muffler. I know my 95 and 97 Silverado had the same hole in itheir muffler too... BTW- I'm not handicapped and I only use two fingers to type

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