Trap Oxidizer Question
 

I called MBUSA and they claim that my car has no outstanding recall issues. I think they may have a database problem because I could swear that it's still there. Correct me if I'm wrong, but the Trap Oxidizer is a footballish-shaped can under the hood just south of the turbo, right?
When I look under the car I can't see anything else that resembles a catalyst. Any recommendations?


By the way.... Many, MANY thanks to you all. This little body of knowledge has helped me to purchase my MB for an intelligent price and address all the running issues with nothing more than 20 dollars in vacuum line tubing and a little patience. You guys rock!

Your signature says you have a 1985 300D. Is that the car in question? If so, I don't think they had a trap oxidizer from the factory. The well known engine with the trap ox. is the 1987 OM603 engine. There was a recall campaign that replaced the exhaust system from the turbo back, and even replaced the turbo if it was required.

Didnt some of the 85's have some sort of california emissions setup?

Trap Oxidizer
 

My limited knowledge (could be wrong) is that the '85 California-only cars had the trap oxidizer. 49 state cars not. Recall was pretty thorough, as with all of MB notices, but cars have slipped by with mailing issues, lazy owners, etc.

Easy to tell if the car has a trap ox. Big hell-for-stout cylindrical can with tapered ends under the aircleaner/turbo assembly, left side after exhaust manifold and ahead of turbo. Your description sounds like you have the disease. Very nasty thing -- kills turbos.

The MB recall is in effect but you might have to find a cooperative dealership for record-checking and the actual replacement work. Problem with the replacement is the internal expense to MB and the dealership mechanics trained on W123's are getting scarce. MB will still bear the cost, some dealers are less than enthusiastic. Nevertheless, get it amputated.

The trap cat on the 1985 300DT California looks sufficiently like the trap ox that you can't tell unless you see the two side by side or you see them all the time so you know which is which or you know the part numbers. They are similar in appearance because they were made to fit in the same space. If the dealer says M-B shows replacement, then it was done.

If you have an 85 Kalifornistani 300D or 300SD and have had the recall work done it will no longer show up on the computers at the dealers as being an outstanding recall.

The recall replaces the trap oxidizer with an oxidation catalyst of the same shape.

Watch out, some practicle jokers may sneek under your hood at night and stick BBs in the vacuum line that operates the air recirculation valve on the turbo. This prank may cause you some confusion as to why you seem to have more power and get better mileage. Its not a very funny joke though as it increases your NOx emissions slightly. Another potential negative side effect of this prank is if you do mainly short trips and don't get many sustained highway miles, your oxidation cat will start to plug up. A good hard drive up and down some steep hills for a couple of hours will clean it out though.

BB Joke
 

Of course if one has a 49 state without the oxy cat, why not commend the practical joker? Had the BB trick played on me, truly wonderful new power and economy. Could also have replaced the EGR valve, as it was sticking in the open position and dumping unburned fuel back into the intakes on accel, thus confounding the ALDA mixing and throwing gobs of nasty black smoke with no guts. I liked the BB trick. Can you predict any long term problems without an oxy cat in an 85 Turbo CD?

It's definitely a Cali car. It has the honkin' huge air filter behind the headlight. I'll post the part number when I get home.

Some jerk in my neighborhood already broke into my garage and ripped the pretty cover off the ALDA adjustment. I was sad to see a rusty nut sitting there instead of the cover. I'll have to watch out for that BB person.