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Stephen Tashiro
02-07-2013, 10:39 PM
I notice that some automotive mufflers have drain holes in them. It's always disturbed me that on my old cars, the drain hole is not at the lowest point in the muffler since the muffler sits at an angle. I'm due to install a new muffler. Any opinions on whether it would help to drill a drain hole where I think one ought to be?

Dan Hintz
02-08-2013, 7:36 AM
As long as it's behind the cat, drill away (if you have state inspections, some anal inspector might take offense to the extra "noise" <rolleyes>).

Jim O'Dell
02-08-2013, 9:05 AM
Not sure it would hurt.... or help. I would think you would need to know how the muffler is constructed internally to know if where you are drilling is the right spot. See if the manufacturer's web site has an exploded view of a muffler, preferably the model you need, to see where the best place to drill would be. Jim.

David Weaver
02-08-2013, 9:21 AM
(if you have state inspections, some anal inspector might take offense to the extra "noise" <rolleyes>).

Now...why would a proctologist have any problem with what he does with his muffler?

:)

Jeff Monson
02-08-2013, 11:31 AM
Funny you should mention it, we have had 2 Audi's and 1 Mercedes in our shop this winter with no start conditions. All 3 would not start when the vehicle sat outside in very cold weather (10 to 20 degrees). After sitting in the shop for a few hours they would start up. The first we had in was the MB, it took us well over a week to get it diagnosed. The exhaust system was full of water and would freeze solid when cold enough, it would block the exhaust system 100% shut, resulting in a no start. First car I have seen in 17 years of business that would not start as a result of water in the exhaust. Well 3 days later we got another cold snap and in came a Q7 audi, had only 43k on it and would not start. We checked all the basics, spark, fuel pressure and ECU codes, all checked out fine. With the MB still lingering in our minds we checked the exhaust and this one was froze up solid also. Later that week we got in another Q7 with the same problem. After these vehicles had the exhaust systems thawed out, we drill a 1/8" hole in the lowest point of the exhaust. All 3 cars had well over 4 gallons of water that was drained from the exhaust system.

Cars built nowdays have exhaust systems that contour the undercarriage much better than the old days, this results in more places for water to accumulate. This coupled with the ethanol in todays fuel can add up to problems.

I remember BMW's having issues with water accumulation in the exhaust system causing the o2 sensors to short out. We fought with many of them, BMW finally came up with a fix for it, drill a 1/8" hole 2" after the sensor to drain the water.

Dan Hintz
02-08-2013, 12:25 PM
Now...why would a proctologist have any problem with what he does with his muffler?

:)

Well, we are talking about tailpipes, aren't we? :p

Stephen Tashiro
02-08-2013, 1:03 PM
The exhaust system was full of water and would freeze solid when cold enough, it would block the exhaust system 100% shut, resulting in a no start.

Whaaa? Wow! Next time that happens, you should make a YouTube about it.

ray hampton
02-08-2013, 2:50 PM
Funny you should mention it, we have had 2 Audi's and 1 Mercedes in our shop this winter with no start conditions. All 3 would not start when the vehicle sat outside in very cold weather (10 to 20 degrees). After sitting in the shop for a few hours they would start up. The first we had in was the MB, it took us well over a week to get it diagnosed. The exhaust system was full of water and would freeze solid when cold enough, it would block the exhaust system 100% shut, resulting in a no start. First car I have seen in 17 years of business that would not start as a result of water in the exhaust. Well 3 days later we got another cold snap and in came a Q7 audi, had only 43k on it and would not start. We checked all the basics, spark, fuel pressure and ECU codes, all checked out fine. With the MB still lingering in our minds we checked the exhaust and this one was froze up solid also. Later that week we got in another Q7 with the same problem. After these vehicles had the exhaust systems thawed out, we drill a 1/8" hole in the lowest point of the exhaust. All 3 cars had well over 4 gallons of water that was drained from the exhaust system.

Cars built nowdays have exhaust systems that contour the undercarriage much better than the old days, this results in more places for water to accumulate. This coupled with the ethanol in todays fuel can add up to problems.

I remember BMW's having issues with water accumulation in the exhaust system causing the o2 sensors to short out. We fought with many of them, BMW finally came up with a fix for it, drill a 1/8" hole 2" after the sensor to drain the water.

do the pipes collect the water because the car are only driven for short trips

Jeff Monson
02-08-2013, 4:07 PM
do the pipes collect the water because the car are only driven for short trips

I'd say that is a major factor in it Ray, also the mufflers are tucked up so far into the bumper and they sit at an angle to where they cant blow out the water like alot of cars do. Ever notice alot of vehicles taking off from a stop and the water pouring out the tailpipe??? Well with the way the muffler sits, there is just not enough flow to overcome the angle of the muffler. They should have drain holes from the factory...but that does result in blackish water dripping on your garage floor.

ray hampton
02-08-2013, 4:32 PM
I'd say that is a major factor in it Ray, also the mufflers are tucked up so far into the bumper and they sit at an angle to where they cant blow out the water like alot of cars do. Ever notice alot of vehicles taking off from a stop and the water pouring out the tailpipe??? Well with the way the muffler sits, there is just not enough flow to overcome the angle of the muffler. They should have drain holes from the factory...but that does result in blackish water dripping on your garage floor.


Thanks to my complains many times about rusting mufflers, they are made with stainless steel now, one fault that most mufflers share is that the tailpipe mount to the muffler close to the center of the muffler end plate, this were the case the last time that I work with a exhaust pipe

Dan Hintz
02-09-2013, 8:00 PM
Thanks to my complains many times about rusting mufflers, they are made with stainless steel now

Are you saying we all enjoy stainless steel mufflers because of your complaints? :confused:

ray hampton
02-10-2013, 1:17 PM
Are you saying we all enjoy stainless steel mufflers because of your complaints? :confused:

until someone else tell you different, I guess that a numbers of car owners complain about having a rusting exhaust system