I'd wager to say that as you look at older and older chassis types you will see that a majority of the examples left are diesels. For example, I'd say most of the /8 cars are diesel, a vast majority of 123s are diesel, sane with 116s. Only when you hit the 126/124/201 do you see a lot of gas engines still puttering away on the road.

Mostly because between 76-86 Mercedes sold about 85% diesels in the US until the oil market crash when MB buyers switched to gassers. You couldn't even get a om617 powered w126 in Europe. It was exclusive to north america.
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Cool Central Coast guy, you are ranting about what I did not say. If a Cal Poly guy, you should work on your reading comprehension before attempting the GRE.

I did not say "environmentalists have always caused more harm".
By "have caused", I meant "have sometimes caused" or maybe even "have often caused". I chose not to qualify because I don't have the full data set.

But, you did stimulate recall of another recent episode. SoCal environmentalists halted a solar-electric project in the desert east of San Diego because the power lines would damage the enviroment or such. They also helped nail the coffin on the technical-plagued 4 unit San Onofre nuclear plant. The result is more fossil-fueled electricity and thus climate change. Some even oppose nice, friendly wind farms (other than wacking birds, though natural selection would eliminate the stupid ones). The Kennedy's couldn't even stand to see wind turbines 20 miles away.

Maybe let's tone down the nastiness? Why do people always get political on these topics? Breathe deeply and think before posting, my friends.

Shortsguy1, I may move to Paso -- we should meet up if I do!

While keeping politics to a minimum, the 3rd paragraph of post 48 is why in # 16 I posted " Is that 1960's VW bus with " Save the planet " really saving the planet? Probably not. "

It takes minimal effort to protest but a lot of effort to actually live green. I wonder how many of the protesters are willing to have no AC in the summer , minimal heat in the winter, combine / eliminate car trips , wash clothes by hand on a washboard in a tub no latest smart phone. . .. Up go the cries that " I can't live without my XXXXX. " Well, 100 years ago everyone did live without XXXXX.

What is one to do? Minimizing waste and unneeded consumption is an excellent step that is easy to do and most practical. There is no need to measure down to the ounce of pollution one makes or suffer for minimal bennefit.

Agreed. Just avoiding processed/packaged foods goes a long way farther than not driving a diesel Mercedes.

The problem is a complex one and everything is more interrelated than people realize. I'm curious what type of emissions my OM603 will have when I get new injector nozzles and lifters installed...I wonder if I could find a smog shop to test it just for S&Giggles.

Time for me to weigh in, I guess. Remember that I have 31 1/2 years in the vehicle emissions business, much of that in Diesel emissions, and I actually know this stuff.

To actually answer the OP's original question:

It's not a simple answer. Diesels are inherently low in HC (unburned hydrocarbons) and CO (carbon monoxide - the stuff that kills you if you run your engine inside a building). These low values can be lowered even further with an aftertreatment system (most folks call that a catalyst but technically it's an aftertreatment system).

NoX (a combination of all oxides of nitrogen emitted, mostly NO and NO2 though there are trace elements of other nitrogen oxides) is a product of heat and time. Compression ignition engines run at higher combustion chamber temperatures and at slower engine speed than a typical Otto-cycle (4 stroke gasoline fueled) engine, therefore more heat and the required longer time for NoX to form. NoX is the catalyst for photochemical smog - HC from engines and other sources plus sulfur oxides mostly from coal-fired power plants plus sunlight plus NoX turns into smog. Nearly all environmental NoX comes from engines. Most can agree that smog is NOT good stuff.

Diesels also generate particulate matter (PM) at much higher levels than Otto-cycles (though both have PMs and Otto-cycles have PM standards coming). The actual PM is not really much of an issue as it's pretty much just carbon. However it IS linked to non-particulate bound organics which are a known carcinogen and a powerful one. Control PM and you control the organics.

As far as feeling guilty - well, no. My DD is a '02 Dodge/Cummins equipped with a sort of intermediate control system. No aftertreatment but electronic injection. Mine also lacks EGR (exhaust gas recirculation) which lowers peak combustion chamber temps (remember that temp/time thing?) and therefore lowers NoX. I get nearly no visible smoke even with the Edge tuner cranked up so PM isn't too bad (there's a loose correlation between visible smoke and PM). But the environmental cost to melt my old Dodge down and make a new one would be much more damaging than to use Truck (his name) out to his useful life of probably 500,000 miles.

So keep on driving and enjoy your old Diesel.

Dan

For the record, I don't giggle when I poop. .

If there are exhaust opacity tests as part of vehicle inspection, the machine should be able to be put into test mode for a check. They should charge somewhat under a regular test. As for other emissions, I'm not sure if a shop is going to be set up for that unless state mandated. ( And there should be a standard posted on your state DMV site. )

I know of some shops that do this kind of testing but not in Oregon. Wisconsin and California, yes. No clue here in NC, either. There probably is someone in your area, though. If you're seriously interested I can see if anyone has a Semtec up there. This is a portable device made for highly accurate emissions measurements on the road but remember that results from a climate controlled lab will differ from on-road. Still, it'll give you a darn good idea - but it won't be cheap.

As I said, the correlation between smoke (also called "soot") testing and PM is pretty loose though there is some linkage. The standards are written in terms of PM and it's an exacting test process requiring a microbalance, a clean room, and impeccable technique. Yes, I've done it.

Dan

Nah, I was just going to see if someone that I knew had a sniffer (the Diesel is back home in CA at the moment) for a gas smog test and shove it up the exhaust and see what happens.

It's always interesting to me how people chose to shame or praise others (or themselves) for one thing, the car they drive, as if it's the only thing polluting our planet. Obviously it's something that if added up across the population is a large factor, but it isn't the only one. At this point I eat almost no meat and don't use a ton of animal products, which collectively also has a massive impact on the environment (and that isn't a joke). I recycle obsessively, use "green" products when I can, don't buy a lot of junk I don't need (i.e., a phone every two years), don't put chemicals in my lawn, don't use a leaf blower, etc etc. But I'm a jerk because I drive a diesel. Not saying I deserve praise or exemption from criticism, but I don't think I need to feel particularly guilty, any more so than almost anyone else in the country should about their habits.

A diesel?

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