Short life expectancy of aftermarket Catalytic Converters
 

I have a 1987 190E 16v. I need to replace an aftermarket catalytic converter that has failed with only 1500 miles of use. The "biscuit" or "cookie" inside the converter can be heard rattling. This is not the first aftermarket converter that has had a short life on this car. In each case the "biscuit" breaks loose.

The car goes through the California emissions check every two years. It passes easily if the converter is good. It fails the test if the converter is bad--typically failing at low speed. (Calif tests cars under load on a dynamometer at a measured speed of 15 mph and 25 mph.)

The car has been thoroughly tested by a Calif licensed special facility. They welded a bung into the exhaust pipe in front of the converter and tested what was going into the converter as well as tail pipe emissions. All systems were good, including the oxygen sensor. Replacing the converter always solves the emissions issue.

My local independent MBZ repair technician says that in his experience aftermarket catalytic converters are notorious for lasting only 1-2 years on older 190 and 300 series cars.

I would appreciate relevant experience that anyone can share.

Thank you very much--Jim

I always though replacement cats are required to have a 5 year 50K warranty according to the EPA?

http://www.discountconverter.com/warranty/index.cfm

Why not get someone parting out a car to sell you a good used unit?

My Cats carried a 2yr. 25K warranty. Since Jan 1, 2009, Cats in Calif must be CARB (Calif Air Resources Board) approved for the vehicle and model and carry a 5 yr. 50K warranty. Up to this point, my Cats have been "universal". According to the muffler shop they were capable of handling a larger engine than in my 190.

My issue is not warranty. I'm trying to understand why the Cats are going bad on an otherwise excellent vehicle.

My only specific input so far is from the independent MBZ tech who said the aftermarket Cats only last a year or two.

Well these older engines like to burn oil....so that is probably half the issue.

I have always used Mobil 1 15-50 with a change interval of never more than 7500 miles. The car uses less than 1 qt of oil between oil changes. I have never had to add oil between changes.

This sounds like one of those things you need to find a good muffler shop with a warranty they'll honor if you buy one of their units and let it be their problem.

Good to know about aftermarket cats. I know what my plan will be if that's the case.

rjp

One of my previous fleet of 16V's had the same issue.
Was caused by the oil consumption issue.

Didn't fix the problem but bypassed the problem by making the catalyst a "BOLT-IN" and having a pipe that would bolt in the same place.

I know that isn't green....but a CIS-E engine isn't green.