'83 240D EGR delete
 

My '97 300D delivery valves started leaking. MB had the o-rings in stock, but the copper washers I had to order. Gonna pick em up this week and "get started". While researching the repair a lot of threads inevitably lead to the carbon choked intake, EGR, etc. The car recently started throwing the P1475 code, too.
This lead me to start thinking about my 240D in this respect, as well. The 240 has 205k, starts right up (winter and summer), doesn't smoke, runs great...bone stock. Always with "if it ain't broke, don't fix it" in the back of my mind, what, exactly, would be the benefit to the EGR delete on the 240? Does performance noticeably improve? Lots of info on the 300D delete and why to do it, but not so much on the 240. Naturally, no codes, limp mode, OBD, etc. nonsense to worry about, so should I be concerned? Or, leave "leave well enough alone"? However, always interested in finding a couple more "poinies" in a car with 67hp brand spankin new (almost 40 years ago).:confused:

I can't speak for performance improvement as far as the EGR delete goes on a 240D but I think it is pretty straightforward and reversible. You could always undo the delete if you aren't impressed or run into trouble.

Thanks. So, that's kinda my point. If the system isn't causing problems (that I'm aware of) and the mod doesn't improve performance (or does it?), why bother. On the other hand, could the intake be severely clogged and coated with carbon and oil residue, such as the E300's I've been reading about? It's definitely slow (everyone knows and says that!). But, it does fine "around town" and on the highway she'll get right up to 60~70 mph and seem quite happy doing it. As is also well known/documented, hills are it's "Kryptonite".....
Don't want to invest time and effort searching for the solution to a problem that doesn't exist.

The first 240 I had, near as I could tell, the EGR valve bound up at some point and hadn't worked in forever. I also had the intake off several times for one reason or the other. With the first motor, it was definately slick with blowby, the second, I never noticed any buildup.

The EGR includes a butterfly linked to the gas pedal that develops a bit of vacuum at idle or part throttle and none at wide open, so it doesn't take in EGR gas when the pedal is floored, which is about half the time on a 240.

So, I don't think it limits performance by buildup or inducing EGR at WOT. If it still works it probably takes the edge off of NOx production, which anyone with breathing problems will appreciate on those bad air quality days.

Thanks "moon". Your comment made me realize that I don't even know if the system is working properly. So, if the EGR valve is bound up, that would only mean more NOx at the tailpipe and not a performance decline?

Call me Andy, and yes, and I don't think it does much to performance anyways. Since it doesn't run an intake vacuum at wide open throttle, I think the only performance impact would be if there was a lot of accumulation in the intake. It's not a hard intake to remove and check, and I've never seen anyone complain about a 240D manifold full of soot from EGR.

Thanks Andy. Appreciate the follow-up! Good to know and "one less thing" to worry about. Gonna enjoy the 240D "as is", for now. As for the E300D....well, that's another story, entirely.

240D EGR Valve
 

If you simply pull the vacuum hose off it, that will disable it .

You can also loosen the 10MM ATF nut and adjust the screw then snug the nut back up .

Sorry...ATF nut?

Acronyms
 

Don't EVER be sorry for asking a question ! .

It means :

Across

The

Flats .

I've been writing Tech help articles for many years now and many ask what size wrench is necessary...

ATF nut
 

Thanks, "Nate". I would've been fine with just "10mm", but it's always good to learn new terminology, acronyms, etc. My question was just me "over thinking" (a terrible affliction I've had for many years..lol). Initially, I thought we were venturing into "A-utomatic T-ransmission F-?" territory...:rolleyes:
Still unsure about the "nut" to which you're referring along with the "adjusting screw"?

OM EGR Valves
 

Look at the top of your EGR valve, if it's original it'll likely have a 10MM ATF nut with a slotted 6MM stud sticking up though it .

Hlold the stud from turning using a slotted screw driver and loosen the nut then turn the stud clockwise until you feel resistance, snug up the nut and you're all done .

Easy-Pasy, lemon squeezy .

Before ever touching the EGR valve you should apply vacuum to it with the engine idling hot ~ it should cause a stumble and rough idle, maybe even stall it out (mostly only gassers will stall) ~ if no change there's no need to do anything as it's already dead .

Not quite.

You see, there will be the previous 40 years of buildup in the intake as well as the butterfly valve ect: that the EGR is may be stuck in the open position essentially robbing you of power.




If you put exhaust gas back into the intake it takes up room for where fresh air could have gone in and oxygen rich air + fuel = good combustion, where as exhaust air with no oxygen means wasted fuel cannot combust and goes out of the exhaust pipe and you try to compensate by pressing down on the accelerator only dumping more fuel in that cannot combust.... making the issue worse.




EGR's make diesel engines less efficient both in fuel consumption and power output.


https://www.youtube.com/watch?v=d3w89xIwZlA&ab_channel=JenniesGarage

That's why I mentioned testing it first ~ you're correct many of these are partially blocked open by older accumulated deposits .

Ahhhh, I see. Thanks for the clarification! So, in other words, if the EGR/parts of system are malfunctioning, it can hurt performance. The butterfly seems to move free and easy but not sure about travel. I'll definitely check into it.