1993 320SL Catalytic converter question

[photomatt]

Hi everyone, I have a 1993 320SL with 186,000 miles that the local muffler shop says the catalytic converters are plugged. Can I run this car "without" them? What will happen if I do? Everything else runs about as close to perfect as an old car can, in my opinion. It certainly isn't a very "green" car to begin with and I only put a few thousand miles on a year in the summer. We also do not have exhaust testing so that will not be an issue. I've benn reading about all this for sometime now on the forums and I just don't have that answer... Thanks!

[zakkkk]

If it were me I would remove them.
The engine will run better

[97 SL320]

Other than the muffler shop saying the cats are clogged, what leads you to believe they are bad?

The exhaust shop can't legally remove the cats, that is Fed law.

[engatwork]

You can remove them but then it becomes for off road use only.

[photomatt]

The problem is that I have no idea how to check to see if they are plugged! For now, I am taking it to another shop to see if they will confirm it. It has been really low on power and just seems to be running like it has an anchor in the ground... It is fully tuned and everything is up to date on it as my regular mechanic that does all the work is the one that said that they are plugged. Is there an easy or "truthful" way to check the convertors?

Thanks!

[97 SL320]

A gauge can be installed in the oxygen sensor port or a 1/8 hole drilled in the exhaust and a gauge clipped on. I don't remember the limit but think it is in the mid single digit range.

Another way is to loosen the pipes at the engine and drive. If performance improves or you hear lots of hissing the exhaust is clogged, then disconnect the muffler and drive again to test muffler.

A clogged cat usually has a hissing sound.

[photomatt]

Thanks! I will look into doing that this weekend when I'm of of work. Is it ok to drive if the cat or muffler is plugged? It all seems to drive fine but just has a huge lack of power while trying to go up a hill and stuff like that...

[97 SL320]

Difficult to tell long distance if car is safe to drive. Cats clog because of a rich mixture burning in the cat causing it to melt. A miss firing cylinder can cause this as well.

Sometimes the ceramic fractures on it's own and packs into the back of cat / muffler.

[C.Doner]

Long term driving on a clogged exhaust can put undue stress on the engine. The timing chain can break over time from overworking. A clogged exhaust is not acceptable IMHO.

[oldsinner111]

depending on your state will tell you if they check exhaust.I think any engine over a 150,000 miles should not have a cat,as oil will only clog it up.

[97 SL320]

Originally Posted by C.Doner

Long term driving on a clogged exhaust can put undue stress on the engine.

A restricted exhaust could make the engine run hotter but no worse than a turbo engine.

Originally Posted by C.Doner

The timing chain can break over time from overworking.

That is a 100% untrue statement.

[C.Doner]

That is a 100% untrue statement.[/QUOTE]

Ok maybe it wont cause it to break. Stretch maybe.
I guess it would take a long time. I just heard from a mechanic long ago that a clogged exhaust can cause undue stress on the timing chain. I have no true experience on the matter.

[engatwork]

Pretty sure it won't accelerate stretch either.

[photomatt]

it is at a local exhaust shop right now getting "test" pipes put in place of the cats... I will know more this weekend on how it is running, etc. It has taken so long to "clog" that I am really hoping that the engine will wake back up! I don't drive it much so I'm sure it will stay in its "test" mode as we do noy have any emissions testing here.

[photomatt]

An update... I haven't had the luxury of driving the car for a few weeks because I found the front flex disc was almost completely destroyed! While I was changing that, I found that the O2 sensor was completely broken off (if I was a betting man, I think that the fragments of the flex disc broke it off as it was flying apart). I am very lucky, felt a weird vibration and stopped driving it until I could have a look under there. So, today I should get it back from the mechanic with a new O2 sensor, replaced flex discs, and a "cleaned out cat". I can't wait to actually drive it again! The couple of miles I drove it before the flex disc broke, it ran like a brand new car!