EGR Picture - PeachParts Mercedes-Benz Forum

C Holmes · #1 01-01-2009, 05:19 PM

Anyone have a picture of where the EGR is located on an 87 300 TDT?

sixto · #2 01-01-2009, 06:34 PM

I don't have a photo editing utility handy so I can't circle the EGR valve but it's the device at the center of the photo.

The EGR valve is attached to the mixing pipe by two bolts that take a 6mm hex bit. It receives exhaust gas through the accordion pipe. The accordion piple is held to the exhaust manifold and EGR valve by a clamp fastened by a bolt that takes a 10mm socket.

There are a number of ways to disable the EGR valve, which is why, I presume, you're asking where it is

:

1) Disconnect and cap the hose attached to the EGR valve. No need to cap the EGR valve end. This does little if the EGR valve is leaking.
2) Slip a solid plate between the EGR valve and the mixing pipe. Exhaust gas cannot get past the EGR valve to the mixing pipe.
3) Cap the exhaust manifold port. Exhaust gas cannot get past the exhaust manifold.
4) [off photo] Disconnect the two plastic lines that go towards the right headlight from the 5-way splitter beside the upper radiator hose. Cap the open ends of the fitting. No need to cap the lines. Or keep the lines connected to the fitting but cauterize the ends or slip a ball bearing to block airflow.

Why two lines? The other line serves the ARV which is less useful than EGR. The ARV is the device below the EGR valve. It redirects boost pressure from the compressor outlet to the compressor inlet. It supposedly softens the onset of boost which helps the trap oxidizer get to operating temperature. Since MB removed trap oxidizers from these cars under recall, there's not much sense in keeping ARV functional.

Do a search on EGR kit. A forum member offers or used to offer a kit that capped and exhaust manifold and mixing pipe so you can keep the EGR valve at home.

Sixto
87 300D

Bio300TDTdriver · #3 01-01-2009, 07:57 PM

Look at Sixto's picture and then go and look at this one. The EGR is missing in this picture, but not in his.

C Holmes · #4 01-01-2009, 08:12 PM

Can I just plug the vacuum line to the EGR without capping? Will it accomplish the same thing or will it leak by?

Bio300TDTdriver · #5 01-01-2009, 08:59 PM

You can plug the line going to the EGR. Some have use a golf tee.

babymog · #6 01-01-2009, 09:04 PM

The neatest method of disabling it without being obvious, is to pull the rubber line, insert a BB, and re-install the rubber line with the BB in it.

sixto · #7 01-01-2009, 09:21 PM

Quote:

Originally Posted by C Holmes

Can I just plug the vacuum line to the EGR without capping? Will it accomplish the same thing or will it leak by?

Not sure what you're asking. At whatever junction you decide to stop the flow of vacuum (yes, I know vacuum doesn't flow, it's actually airflow the other way, but let's think of vacuum as a commodity in this discussion), it's important to cap or plug the vacuum end of the junction.

If you want to accomplish this by blocking the vacuum signal at the EGR valve, slip a bb into rubber fitting between the plastic line and the EGR valve as babymog suggests. Vacuum signal won't get to the EGR valve, air won't leak into the vacuum system. In my case, I don't have bb's lying around so I heat the tip of the plastic line with a match and pinch it sealed with my fingers. Put everything back in place for looks.

Sixto
87 300D

C Holmes · #8 01-02-2009, 04:50 AM

OK, I want to disconnect it temporarily to see if it makes any difference, some say it does and then there is the other side that says it makes no difference.

babymog · #9 01-02-2009, 10:41 AM

I don't believe that it makes a noticable difference in performance.

What we try to accomplish by disabling it, is keeping the intake tract and valves cleaner. The soot from the exhaust otherwise mixes with the oil vapors from the crankcase, making a very nice tar-like substance in your engine's intake and valves.

Jeremy5848 · #10 01-02-2009, 12:32 PM

Agreed. If your intakes are VERY badly crudded up and you remove them and completely clean them out as part of defeating the EGR valve, then you might see a slight improvement in performance and/or fuel economy. However, you could get the same improvement with a good imagination and it would be a lot less work.

I didn't notice any improvement in my '85 or my '87 but think (or imagine) a slight improvement in the '96, which was badly clogged. In any case, I felt a lot better with clean intakes, and they are staying clean, which makes them a lot easier to handle when I remove them for glow plug work.

Jeremy