W126 M103 Egr - PeachParts Mercedes-Benz Forum

sixto · #1 06-24-2002, 04:37 PM

My 91 300SE originally delivered in CA has an EGR valve on the forward exhaust manifold. I looked at an 89 300SEL originally delivered in VA and it doesn't have an EGR valve that I can see. Is there no EGR system on the earlier cars?

Thanks,
Sixto
91 300SE
87 300SDL

unkl300d · #2 05-04-2009, 03:41 PM

Hey Sixto, my 1989 300SE has no readily visible EGR valve on the forward exhuast manifold.

However Fastlane does indicate that my model has an EGR valve.

By the looks of some vacuum lines, it looks like it may be installed deep under the air cleaner housing.

Comments?

BTW is this EGR valve cleanable (proactive maintenance) w/o removing it?
Like with some WD-40 or brake cleaner spray??

Cal Learner · #3 05-04-2009, 03:45 PM

EGR and air pump were added to M103 motors beginning in MY 1990, even on Calif cars.

S-Class Guru · #4 05-04-2009, 03:56 PM

My '91 300SE from Texas has the EGR sitting right up on the exhaust manifold.
I've had to replace it once; it came right off with two bolts and didn't even tear the gasket. No real carbon buildup on the underside; I guess that's because it stays very hot sitting right on the manifold. However, the pipe runs from there around the back of the motor and into the underside of the intake manifold. That's where the carbon clog occurs. I've heard about running an old speedo inner cable thru the pipe to clean it out, but on the SE it's pretty asccessible from underneath.
A quick way to check if it's clogged is to idle the car, pull and plug the EGR vacuum line, and then apply vacuum to the EGR via a MightyVac. If the engine stumbles the EGR line to the intake manifold is still open.

DG

unkl300d · #5 05-05-2009, 01:34 PM

Cal Learner, thanks for this information.
I wonder why Fastlane indicates an EGR valve for the 1989 300SE?

I don't doubt your information but perhaps what the parts catalog refers to is ambiguous or ???

pawoSD · #6 05-05-2009, 04:33 PM

I disconnected the vacuum line to mine.....just like on my diesels....

S-Class Guru · #7 05-05-2009, 07:43 PM

The only downside to disconnecting the EGR is it will make an engine more knock-sensitive at part throttle loads. But if you run premium fuel, and haven't messed with the timing resistors, there is little chance of that on the 103. For those that happily buzz along on regular, a functioning EGR would be beneficial.
Hope I didn't reopen the fuel octane debate.

DG

tinypanzer · #8 05-05-2009, 07:55 PM

Before it goes that direction, I'll steer it another way:

How hard is it to ditch the air pump? Can I just pull the air pump and short belt it, or would I need to add a pulley?

I've never seen a 300SE or similar that didn't have the air pump setup, so I can't really visualize what it would look like without it......

Hit Man X · #9 05-05-2009, 09:43 PM

Quote:

Originally Posted by tinypanzer

Before it goes that direction, I'll steer it another way:

How hard is it to ditch the air pump? Can I just pull the air pump and short belt it, or would I need to add a pulley?

I've never seen a 300SE or similar that didn't have the air pump setup, so I can't really visualize what it would look like without it......

Easy, just remove it and use the early belt. I went past that and used early alt bracket, early fan bearing bracket, etc. I can get pics if you want. Hell I even put in a W140 V8 alt and now I have 150A .

tinypanzer · #10 05-05-2009, 10:28 PM

Quote:

Originally Posted by Hit Man X

Easy, just remove it and use the early belt. I went past that and used early alt bracket, early fan bearing bracket, etc. I can get pics if you want. Hell I even put in a W140 V8 alt and now I have 150A .

Wow, that's pretty slick of you! It could never hurt to have some extra alt output, especially considering the stereo that the PO put in my car. At first I thought $3500 was a bit high for a 300SE with failing paint, but when I saw that he dropped well over a grand on an MB quart system with a Clarion head unit and a complete Siruis setup I capitulated.

I'd love to see a pic of how you did that, if it's not any trouble.

So, you're saying that if I just delete the air pump and order a belt for a pre '90 300SE, it will fit? If so, then cool!! I'm not sure I have the energy to deal with bracket swaps just yet, perhaps I'll save that until it's time to deal with the fan clutch or water pump or belt tensioner.....

Thanks for the info!

Hit Man X · #11 05-05-2009, 10:58 PM

Yeah, I'll get a pic or two in the day light.

I had to replace my belt and the alt took a crap as well as reseal the upper timing case cover, so I went ahead and swapped it all over.

PM me and remind me.

Cal Learner · #12 05-06-2009, 07:33 AM

Quote:

Originally Posted by unkl300d

Cal Learner, thanks for this information.
I wonder why Fastlane indicates an EGR valve for the 1989 300SE?

I don't doubt your information but perhaps what the parts catalog refers to is ambiguous or ???

A clarification: EGR was added to your motor from engine serial number 181462, which puts it just about start of model year 1990, but there was a handful of earlier, individual motors that got the EGR. Maybe those were technically considered MY 1989, although I tend to doubt it, b/c the on-board diagnostic coupling (X11/4) with pushbutton switch and LED in 1988 and 1989 models only goes to 10 pulses, none of which denotes EGR. In MY 1990, EGR was added as one of the stored faults (12 pulses). Maybe there's an owner out there with a 1989 that has an EGR and can chime in; never heard of it though.

unkl300d · #13 05-06-2009, 12:38 PM

I still think you are correct. In any event my 300SE passed the california smog test yesterday and the doc states that the EGR visual and functional is N/A, not applicable.
This was the case in prior years, its just that this year I recently had a problem with turbulent idle that I recently resolved with new spark plugs and cleaning the distributor cap.
The EGR question came to my mind as I mentally ran variables that might cause the test to fail my car.

Thanks

pawoSD · #14 05-06-2009, 02:56 PM

Quote:

Originally Posted by S-Class Guru

The only downside to disconnecting the EGR is it will make an engine more knock-sensitive at part throttle loads. But if you run premium fuel, and haven't messed with the timing resistors, there is little chance of that on the 103. For those that happily buzz along on regular, a functioning EGR would be beneficial.
Hope I didn't reopen the fuel octane debate.

DG

I haven't messed with the timing resistor and I do only run it on Premium (with Redline SI-1 added on top of it)....it gets an expen$ive diet.

So far I think its actually been running better than before I disconnected it.

When my air pump starts sounding ill, I am going to delete it as well...currently it works smoothly, so I may as well leave it alone....

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