Muffler Weep Holes?

[Mike B.]

Every time I start my '61, a noticeable puddle of condensation forms beneath each tail pipe. I am wondering if it would be prudent to drill small weep holes on the lowest, downward facing section of each muffler to alleviate the potential for internal corrosion. They are the standard oblong shape and are relatively new.

Opinions please.

Thanks, Mike

[Chris E.]

Re: Muffler Weep Holes?

I have heard of doing just that on midyear mufflers. I imagine the same thing would work for the solid axle cars.

[James W.]

Re: Muffler Weep Holes?

Mike,

My family owned several exhaust business when I was growing up. My dad drilled a 1/16 of an inch or a 3/32 of an inch in diameter hole at the lower point on the end cap of the mufflers on all of his Corvettes. We offered that as an "option" to customers who did a lot of low speed, in town driving to help prolong the life of their new exhaust system since in a small town, driving distances were short and did not allow the engine or exhaust system to get hot enough to evaperate the moisture in the exhaust system. Most people had us drill the hole.

Just use a few drops of water on the rolled edge of the muffler and that will tell you exactly where to drill the hole. Every once in a while use a torch tip cleaner or a paper clip to be sure the hole stays open.


Best Regards,

James West
Omaha, NE.

[Mike B.]

Re: Muffler Weep Holes?

James,

Great tips from a guy who's been there and done that!

You gave me the confidence to get out the drill along with a better technique than "eyeballing" to find the exact spot to drill.

Thanks,
Mike

[Joe L.]

Re: Muffler Weep Holes?

James,

Great tips from a guy who's been there and done that!

You gave me the confidence to get out the drill along with a better technique than "eyeballing" to find the exact spot to drill.

Thanks,
Mike

Mike----

Actually, some PRODUCTION and SERVICE mufflers for some cars, although never Corvettes, did have these holes. Why Corvettes did not have them is beyond me. It might have been related to some "legal staff" opinion that such holes could allow exhaust gases to get into the passenger compartment. Or, it may have been that GM wanted to sell a lot of SERVICE mufflers ( I really doubt this, though; I don't generally subscribe to the notion that auto manufacturers would ever operate that way).

One other thing: if you eliminate the heat riser on the right side, you almost don't need the holes.

[Kirk M.]

Re: Muffler Weep Holes?

Shoot, who needs to drill 'em, mine just rusted through in the right spot!

[Pat M.]

Re: Muffler Weep Holes?

This is a timely subject for me, as I was discussing doing this to my 70 with a friend just this morning.
The factory mufflers on my 96 have weep holes, and a relatively large amount of water comes out every time the car is run.

[John H.]

Re: Muffler Weep Holes?

Most OEM mufflers on other Chevrolet car lines had a 3/32" hole pierced at the bottom of the inlet side cap for condensate drainage.

[Stuart F.]

Re: Muffler Weep Holes?

It seems, in general, mufflers located at the rear of the car with long exhaust pipes run cooler and are more susceptable to holding condensation longer - and rusting out. Case in point the Novas with the cross flow muffler by the rear axle. With that almost a given, it is hard to understand why Corvettes didn't have weep holes. I'm on my fourth system in 45 years (not bad, hey?), but that is with only 44.5k on the clock. My last set is the aluminized steel which has lasted since 1992 so, I believe it is safe to say that some of the corrosion came about that way, but some of it was also from external sources, like maybe concrete floors and road contaminents (but then my frame should be a lot worse than it is).

Stu Fox