It would be nice to have a Mercedes star stamped onto the cover plate.

I just bought an 83 300 D and when fixing the vacuum leak from the door mechanisms so my car would shut off with the key, I saw that whoever had the car last plugged the plug output to the EGR with a bolt and left the place where the tube should go on the EGR open.

Should I plug the EGR or is is ok to leave open?

Mine doesn't but I think my engine might be from a different model
Just look for the ugly beast on the intake manifold.

Has anyone bothered to point out that the EGR on diesels actually helps lower the combustion temerature and the exhaust gas temperature. These are both good things. High combustion temps and exhaust temps are some of the few things that will kill a diesel. Lowering the combustion temperature reduces NOX emissions, lower exhaust gas temperature drasticly extends turbo life. In a turbo diesel there is already more than enough oxygen in the combustion chamber, disabling the egr isn't helping combustion only making it a lot hotter than it should be for a long lived diesel. If I were building a higher performance turbodiesel I wouldn't remove the EGR unless if was for a full out competition engine. For a daily driver EGR is a GOOD thing and doesn't hurt power.

As for the gunking of the intake manifold, EGR isn't the culprit there either. The gunk deposited in the intake manifold is from the crankcase vent. Volotile hydrocarbons from the crankcase are vented before the turbo. They get very hot after the turbo and the lighter componets evaporate leaving the heavier componets behind to form the gunk. Since the EGR valve is even hotter than the turbo a lot of gunk gets deposited there as the more volotile stuff evaporates. Think about it, what does the inside of the diesels exhaust pipe look like or for that matter the hot side of the egr valve. It's only a thin dry film of carbon. IF the EGR was the cause of deposits those would also be a thin dry film, and not the thick gooey gunk that cloggs diesel intakes.

Sorry for the rant but as a responsible hot rodder I get miffed at people who automaticly assume that disabling emissions equipment is the only way to make power. Don't even get me started about all of the wanna be racers removing the catalyst from their 16 second car to make it a 15 and 3/4 second car. I've built several fast street cars and make it a point to keep emissions related equip. in tact. That way when hotrodding is regulated out of existance I'm gonna be the one pointing at you.

The reason the gunk is formed is because the egr lets soot get through the intake. These cars are turbo charged and some oil always gets past the bearings. Throw that oil in with the soot and let it cook for 15 years and you have a nice mess.

Btw euro 603's never had egr's.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

The engine was designed and engineered to run without the EGR.
I have opened 150K mile MB diesel intakes, found ten millimeters of soot sludge coating the inside, and the engines did not have blow by issues.
EGR was added to the OM617 only as an after thought to meet USA emission demand.
Oil from the crankcase vent tube flows through fairly clean, when soot is added it becomes a thick sludge that builds up and effects engine performance.
Many of us do not care about the emissions because we run vegetable oil for fuel = emission is not applicable.

Note:
These cars do not, and never did have a catalytic converter...

EGR's are also meant to help reduce NOx, HC, and CO emissions, by recycling the exhaust gases for another go through. It forces the NOx to separate back into N2 and O2, which allows the O2 to finish reacting with the HC and CO to create CO2. So removing the EGR will get rid of the gunk in the intact manifold, increase part load power, clean up the engine bay, and possibly increase fuel economy, but will also increase emissions.

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1985 300SD "Battleship"

Disagree:
On the older OM61x and OM60x engines, removing the EGR has minimal or no detectable effect on emissions.

It was installed to make CARB and the EPA think they where concerned about emissions.

If the engine is in good condition it will pass the required testing without any EGR.

.

I doubt this, NOx is much higher without erg. I know the 84 / 85 617 cars failed emissions testing when the EGR is broken.

I should hook up a test light to the EGR output on my computer... See when it's active.

If not needing EGR is a metric for how good an engine is that means VW trumps MB, VWs didn't get EGR here until 1995

Many modern passenger cars have 2 EGR systems so they can run even mor EGR, and while on boost :crazy:

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Emission gas readings are irrelevant, the only EPA spec for 1985 and earlier is opacity.

Your vehicles failed opacity??
No state can legally fail these engines for any other reason.

.

Three points whunter:
1) The opacity emissions test will not be a problem for CO or NOx emissions as both gases are relatively transparent. Opacity is mainly a good way to measure the health of a diesel engine in order to get a rough idea of it's health (too much soot or HC are signs of a unhealthy engine, or running way too rich when loaded).
2) The government sets up emission standards for both the engine itself at the design level and out the tailpipe for after purchase validation of a properly operating vehicle.
3) I've ran experiments on diesel generators during my college days. I saw first hand what different loads, EGRs, and biodiesel will do to a diesel engines emissions and efficiency. Just like anything else, it's all a balancing act. Some things, like EGRs, that are meant to reduce emission also reduce the thermodynamic efficiency of the engine which results in less power and worse fuel economy. This is the reason that some diesels can see an increase in fuel economy and power after advancing the injection timing a little past OEM specs (of course not too much).

I'm not suggesting that anyone shouldn't remove their EGRs, quite the contrary, I'm a big fan of it on old diesels especially when you live out in the middle of nowhere like i do and have no mandated emission testing. I like the improved throttle response and fuel economy. I'm just realistic with the consequences as well. By the way, testing has shown that modern vehicles run so damn clean that in some cases the exhaust coming out of those vehicles is cleaner than the air that went in. For that reason, I removed my EGR and balance the air quality by driving in front of a new car when possible .

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1985 300SD "Battleship"

The issue I seem to have is those new cars won't stay behind me. Am I driving too slow in town? Between each traffic signal, newer cars zoom around me, only to be in front of me at the next traffic light.

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
No longer selling Cluster Needles Paint
No longer selling New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

I suppose that's true, but that's kind of a tricky response... "They can't tell it's broken" vs. "They don't care". It still violates EPA regs. Weather or not NOx is actually bad for the environment is another debatable topic.

Check out this thread:

EPA Test of the Trap Ox on 85 617s

I'd love to get the NOx differences on my car... but when I started testing the EGR I think I misplaced all the vacuum lines for it

I would venture that most 617s running around today have horrible tailpipe emissions compared to when they were new... retarded timing from stretched chains and worn injectors probably make a ton more PM and HC.

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.