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...

I'd have to disagree with you about the soot in the intake. As an m/b tech I work on a lot of different cars. The gasoline cars have the same problem. The M104 tends to clog it's EGR port but only within a few inches of the intake, shortly after where crankcase fumes are mixed with incoming air. The pipe is over two feet long and only 10mm od. However it only clogs up right where it goes to the intake. Same thing as with the diesels, the crankcase vapor gets very hot near the EGR port and evaporates the lighter components leaving the crud to block the port. Not nearly the soot as in diesels but the exact same phenomenon happening.
Even without EGR on a turbo diesel the heat from the turbo would evaporate the lighter components of the re-cycled crankcase vapors and still crud up the intake. Granted the soot isn't helping the situation but isn't the root cause of the problem.

I'd be willing to bet that the euro 603's have either a different part # injection pump or less total timing (and probably both) With EGR the exhaust gas acts as a buffer during combustion, allowing the mixture to burn slower, which in turn allows you to extract power over more degrees of crankshaft rotation. Without egr the burn is faster which results in a spike of combustion pressure early and no usable energy late in the stroke. The difference between the two burns is like the difference between shoving a door open and running face first into it at top speed. Either way may open it but which way do you want to repeat 3000 times a minute?

Hello duxthe1

The OM617, all the data I have states that MB achieved USA emissions with stock European parts.
#1. USA cars ALDA is OEM preset minimum lean + EGR is added, timing is identical to European.
#2. A trap oxidizer was added on California models, can't recall what year.

One of the most popular modifications is to tweak the ALDA for higher fuel output = more power.
Your statements are true for a gasser, and possibly for newer diesels, but do not apply to OM617 and earlier diesel engines.

If the EGR isn't gunking up my intake then tell me why the back side of the valve and the hole that it feeds its exhaust into the intake was almost plugged on my 300SD when I got it. The turbo OUTLET was clear and the concentration of gunk was around the EGR port, not near the turbo outlet/inlet side of the intake manifold.

I disabled my EGR and have reasonable blowby. 25k later there is NO gunk. There is light oil but no more thick gooey sooty crap.

And if its coming from the crankcase ventilation system then why don't interoolers plug up every 50k? It would seem like they would be seeing the same "hot side of the turbo" oil problem that the intake was seeing.

EGR cools the combustion yes...but it also contributes to the intake being filled with

No golf tees in the house,no BB's.

Gimme something else to work with, please.

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79 300SD - $50 out of pocket purchase
03 Dodge Ram 3500 CTD
2003 VW Jetta TDI

cut off a short, straight section of tree branch, somewhere down near a leaf that will fit tightly. About 1/4 inch long and shove it in there. Bad idea for a treehugger maybe?

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

The best solution is to remove the hose completely. The opposite end is connected to a coolant switch. Stop by your local auto parts store and get a suitable rubber cap for the open nipple on the coolant switch. Makes for a clean installation.

Dang, I keep searching for a good used EGR on eBay but can never find one... Are these things that rare???

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PagodaLOVER
1967 230SL, manual
1959 180D, manual

Hah if you want one..I will sell you my old one (I have an extra one too off of my new intake)

Lemme know

Heck, if I could gain 0.25 sec from dumping the cats on both my trucks I would (that's over 20rwhp!)... but in reality I'd pick up maybe 7rwhp and it's not even a full 0.1 sec in the 1/4 mi quicker. Waste of my time. Both of mine run high flow cats.

EGR on diesel also creates boost pressure loss which slows down spooling time. Heck, GM's Duramax from Isuzu finally received EGR for the '04.5 model year... read up on how much better the motor performs with it removed.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

They're just so darn pretty

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PagodaLOVER
1967 230SL, manual
1959 180D, manual