drilling muffler to reduce condensation

[old cool]

Hello again. I've been using the question box on a regular basis. Great resource. I'm making headway thanks to forum users. You guys have given me more feedback than any local car enthusiasts (I think they avoid getting involved). Very thankful to you all.
Something that I've been unable to find on this forum is getting the condensation out of the muffler after shut down. My muffler is tilted downward toward the front of the truck. So, I get condensation that splatters out pipe on start-ups. NO condensation evident after truck is driven.
So, I've been reading up on drilling a 1/8 inch hole at low point on muffler. Many non-forum people say that was SOP on many vehicles. Others say it may make noise; others say it doesn't make noise as there is not enough pressure at the low/front part of muffler. Some say exhaust smell (that I would surely steer away from).
Any thoughts or opinions would be appreciated.

[jayoldschool]

The standard stainless steel dual mufflers on the 94-96 LT1 RWD GM cars had drainage holes at the back of the cases on the bottom.

[markeb01]

That's not something I've ever heard of, and I wouldn't recommend it. Condensation in a muffler on start up is normal, as the moisture in the outside air is drawn into the pipe and "rains" inside. The best method for long muffler life is driving the vehicle long enough to dry them out every time the engine is started. On a daily driver with a short commute this may be impractical.

This is why Sears, Montgomery Wards, and Penney's dropped dual exhaust applications decades ago. Single exhaust systems warm up faster and dry out the mufflers more quickly than duals. So they greatly reduced their warranty replacements by eliminating dual mufflers that rusted out faster.

Drill a hole of any size in the muffler will make it sound worse (like a muffler leak) and will also introduce carbon monoxide into the cabin depending on where the muffler is located.

[spacedebris]

there are many opinions about this. Its one of those "It's like a**holes, everyone has one" situations.

IMO, drilling a hole in the muffler is simply an intentional exhaust leak. Now discounting things like catalytic converters for smog reasons and mufflers for sound, the whole point of an exhaust system is to get the exhaust away from the cabin and the people in it. Drilling a hole in the muffler brings those fumes back into an area that your trying to keep it away from.

Another problem with drilling a hole is that many mufflers are coated with an "anti-corrosion" coating and by drilling a hole your compromising that coating.

Now in the rice-burner following many are in favor of drilling a small hole for removing the water and you can even find many videos showing that some of them are getting an 1/8 of a cup or so of water out after shut down. They insist that by removing this water they increase the life of their mufflers. But what they either dont think about or dont realize is that in very short order that hole they drilled will simply clog up with rust (compromised coating) or with simple minerals in the water will clog it up. Remember that things like carbon come out the tail pipe and it will not be long before smutz will clog up that tiny hole.

It is my opinion that spending the $50-$100 every 10 years for a new muffler is better than the alternatives.

[old cool]

Correct tips from everyone; that's why i bought it to the forum. Should have mentioned I have a '66 gmc no emissions other that breather and pvc (inline 6). Problem is the 1/4 cup of spray with some carbon in it.
As I mentioned, I do not want leak sound or dangerous gases. However, it is done over and over; and standard on some vehicles. Prob won't do it but thought I'd ask.

[BigDan3131]

Buy better quality gas, the no name stuff is as bad as Arco. Meaning the level of water in it is higher and as of late they added even more ethanol to the gas. I'm lucky that I have a farm gas place to buy from, its ethanol free.

[old cool]

Big Dan. I've done some reading on Top Tier fuels in the past. I usually went after fuels that had an additive such as Techron. I only bought them as my German made sports car (sorry about that-my first and last) was always in storage and it liked to be fed on something that kept the injectors and other fuel system components clean. I'm not here to promote additives, but to some level, they reduced carbon and residues brought on by older gas. I did notice a difference when using Top Tier fuel.
However, I don't think that's what you mean by "good" gas. I see you can buy pure gas (no ethanol) at various farm stores but I cannot find a gas station that sells ethanol free petro. Problem is also going to be cost. I'm already spending 4 bucks a gallon and getting about 12-13 mpg with a inline six backed by a 3.54 gear. Assuming pure gas is going to be too much, what are the other alternatives? Is a pint of dry gas (about $1) at fillups worth looking into?
I should mention, I agree with Markeb that it helps to drive the truck long enough to have some drying benefits. It's just not always convenient. It also means I "mark my territory" on someone's driveway. Hence, I typically park by the curbs. LOL
I'm still wondering why there are so many good reports about drilling a hole. Puzzling.

[newbe351]

[QUOTE=markeb01;6742520]Condensation in a muffler on start up is normal, as the moisture in the outside air is drawn into the pipe and "rains" inside. The best method for long muffler life is driving the vehicle long enough to dry them out every time the engine is started. On a daily driver with a short commute this may be impractical.QUOTE]


Actually, condensation (water) is a by-product of the combustion process. It is not "drawn in" (well, it probably is to a degree but the real culprit is combustion). Even in Arizona you see water coming out of tailpipes in the morning when everyone is just hitting the road. Same issue with condensation in the engine. The only viable alternative is to drive until everything heats up enough to evaporate it (oil and muffler). I run mine as a daily driver with a very short commute and it is an issue. But I don’t think extra holes in the muffler is the answer……

[padresag]

[quote=newbe351;6743757]

Originally Posted by markeb01

Condensation in a muffler on start up is normal, as the moisture in the outside air is drawn into the pipe and "rains" inside. The best method for long muffler life is driving the vehicle long enough to dry them out every time the engine is started. On a daily driver with a short commute this may be impractical.QUOTE]


Actually, condensation (water) is a by-product of the combustion process. It is not "drawn in" (well, it probably is to a degree but the real culprit is combustion). Even in Arizona you see water coming out of tailpipes in the morning when everyone is just hitting the road. Same issue with condensation in the engine. The only viable alternative is to drive until everything heats up enough to evaporate it (oil and muffler). I run mine as a daily driver with a very short commute and it is an issue. But I don’t think extra holes in the muffler is the answer……

on very short commutes there is always an alternative and may be beneficial to you; it is called getting off your ass and walking or riding a bicycle. that is what I do. for many years I ran a 4 cyl detroit and it took a while to get up to temperature and trips got shorter and shorter. very seldom do I ever go through a tank of gas in a month. it was better for my eng and for me to walk and or ride 1 of my bikes. the dogs also get to enjoy the walks
ron

[newbe351]

[QUOTE=padresag; on very short commutes there is always an alternative; it is called getting off your ass and walking or riding a bicycle. QUOTE]

Cute. I'll include that in the bike forum next time I'm there. Mostly I just drive a lot further than I need to just to warm things up.....

[padresag]

I don't know about the word cute though.
ron

[61_FL_Apache]

Originally Posted by jayoldschool

The standard stainless steel dual mufflers on the 94-96 LT1 RWD GM cars had drainage holes at the back of the cases on the bottom.

My 94 Caprice was like that.

[luvbowties]

[QUOTE=markeb01;6742520]That's not something I've ever heard of, and I wouldn't recommend it...(cut)

Mark, I'd have sworn you were old enough, ALSO, to recall that some mufflers in the 50's (maybe into early 60's) had holes drilled into their rears.
One case in point, one farmer whose vehicles we serviced bought a new International 1/2 ton, v-8, 3-speed, with duals, from the factory. Both mufflers had approx. 1/8-inch holes drilled in the back bottoms.

BTW: that truck would bark the wheels in ALL 3 gears--high gear could be made to bark 3 times, sometimes; just twice sometimes!

Also, iirc, some replacement mufflers that Western Auto sold had holes drilled in the rear.

But to o/p, I'd not drill holes in my mufflers. Do like mark and others may have said: drive it far enough for it to warm up completely before shutting it down--better for engine as well as mufflers.

And, mark I apologize for thinking you were old like me!
Sam