Results of a study about what the trap oxidixer does and how effective it is.... (somewhat general, but still interesting)

http://www.arb.ca.gov/research/resnotes/notes/89-3.htm


So, you SDL owners, many have removed their trap oxidizer but Mercedes will replace it for free. Anyone know what fuel economy difference and drivability differences there are with and without the oxidizer installed?

-m

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Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

The scoop on trap oxidizer replacement:

My brother's plugged this summer. We found the following:

MB will NOT replace the trap oxidizer until it plugs. There are a couple recommended cleaning steps one can perform once or twice, after which the trap will be replaced.

The "replacement" is NOT a trap oxidizer -- MB had to have something in order to sell the cars in California in 1986, and the trap oxidizer was the only solution available for immediate use. Since it was known to fail rather quickly, a warrenty replacement for the lifetime of the vehicle was instituted, with the intention of installing something better. The better is a plain pipe in front of the turbo and a catalyst in the exhaust downstream of the turbo.

When the trap fails, it plugs. Not the other way round! It also usually blow crumbs of ceramic matrix down the turbo, with the result that the turbine is worn off and boost disappears.

Typically, MB will insist that the trap be replaced (with an insulated pipe where the trap used to be and a catalyst in the new tailpipe you get!), but will not install a new turbo unless the old one is bad on inspection (duh?). In my brother's case, this meant two trips to the dealer since he refuses, rightly, to leave the car one second longer than it takes to do the work -- horrible dealer, I've had very bad experiences there for more than 20 years! Had to drive the car for weeks with 3 lbs boost from a dead turbo while they screwed around ordering the wrong one, etc -- and they only order parts once a week!

I've not gotten a report on performance since then -- poor guy doesn't get to drive the car much! His wife refuses to drive any of his older cars. He should get performance similar to my 300D -- vastly better than what he had!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Huh, my previous 300 SDL had the trap taken off and rigged with a pipe by an independent mechanic. Looked kinda hodge-podge but worked fine. This current SDL I'm looking at is at a MB dealer and it looked like the pipe installed was new. They probably just did it as they got it in.

Environmentally, I was pretty happy to see that it caught so much more stuff from polluting the air. But for drivability reasons, I'm glad its removed!

-m

PS: What do you use to keep your upper engine metal so clean? The SDL I'm looking it is quite dirty and I'd like to clean it if I end up buying it...... (like the big metal piece that goes horizontal across the engine)

__________________
Now:
2018 Tesla Model X
1999 S500 Grand Edition 164k
1992 300D 2.5 Turbo 287k
2005 E320 4MATIC wagon
1991 Alfa Romeo 164L 99k (sleeping for a while)

Then: 96 Lincoln TC, 93 Lincoln TC, 87 560 SEL, 87 300 SDL, 80 300D, 89 560 SEC

Peter, if you are in the US, MBNA does have a recall on the trap oxidizer and *will* replace it, one time per car, independent of mileage, independent of number of owners, and whether or not it has plugged. If your dealer is a US dealer and your car is a US car, then your dealer is giving you incorrect information.

There is no cost to you for this recall and all the dealer has to do is check MBNA records and see if the recall has been performed on your car before; if not, they'll do it -- free.

Richard Easley
Waco, Texas