1993 300d om602 Exhaust Manifold EGR Hole Plugging Conundrum - PeachParts Mercedes-Benz Forum

903hblue · #1 04-29-2017, 04:19 PM

After dismantling the mixer housing EGR stuff from the exhaust manifold, I am left stumped with how to plug the hole in the exhaust manifold.
After a lot of brainstorming, multiple trips to hardware and auto parts stores, I've come to the conclusion I will probably need to tap and plug the hole. A 3/4 inch pipe plug (brass or steel?) seems like good way to go. This is where I am left very confused, since I have no plumbing and little tapping experience.
What pipe tap will leave me with the proper threads to fit a 3/4 inch plug? There seems to be a difference in how inner and outer diameter are translated in this realm.

Maybe there is another, more simple and cheap way to do this?
Thank you guys in advance!

dieselbenz1 · #2 04-29-2017, 04:35 PM

I stacked 3 washers the approximate diameter as the pipe you removed put a bolt through them to seal it closed then used the same circular mounting clamp.

jay_bob · #3 04-29-2017, 04:55 PM

Message forum member rollguy he made a kit for this

For Sale: EGR Delete/Block-off Plate Kit

903hblue · #4 04-29-2017, 06:59 PM

Quote:

Originally Posted by dieselbenz1

I stacked 3 washers the approximate diameter as the pipe you removed put a bolt through them to seal it closed then used the same circular mounting clamp.

That is an interesting solution, and actually I did consider something along those lines, but how does the bolt stay in? Won't the exhaust gases find a way threw?
On eBay I saw stainless discs (with no hole) but then I figured there would still be a leak, even with the clamp on. Maybe not though?

903hblue · #5 04-29-2017, 07:02 PM

Quote:

Originally Posted by jay_bob

Message forum member rollguy he made a kit for this

For Sale: EGR Delete/Block-off Plate Kit

Thank you, but it looks like that kit is designed for the om603. Once the mixer housing is removed on the om602 all that is left to plug is the hole in the exhaust manifold.

dieselbenz1 · #6 04-29-2017, 10:11 PM

I used some exhaust paste the bolt through the washers has both a nut and bolt holding the washers together. No problems 5 yrs.

sixto · #7 04-29-2017, 10:25 PM

Can you cap it with a freeze plug?

Sixto
83 300SD
98 E320 wagon

903hblue · #8 04-30-2017, 01:45 AM

Quote:

Originally Posted by dieselbenz1

I used some exhaust paste the bolt through the washers has both a nut and bolt holding the washers together. No problems 5 yrs.

I will try this, thank you! Did you also use paste between the manifold opening and the washers? Seems like that would be good insurance.

903hblue · #9 04-30-2017, 01:53 AM

Quote:

Originally Posted by sixto

Can you cap it with a freeze plug?
Sixto
83 300SD
98 E320 wagon

Well the inner diameter of the opening seems to measure about 11/16, which is hard to find a freeze plug that diameter. Then I thought tapping it in the opening could lead to more issues, i.e. plug blowing out.
I already tried to cap over the whole "spout", but 1 1/2" was too small, and 1 5/8" was too large!

tjts1 · #10 04-30-2017, 02:29 AM

Quote:

Originally Posted by 903hblue

After dismantling the mixer housing EGR stuff from the exhaust manifold, I am left stumped with how to plug the hole in the exhaust manifold.
After a lot of brainstorming, multiple trips to hardware and auto parts stores, I've come to the conclusion I will probably need to tap and plug the hole. A 3/4 inch pipe plug (brass or steel?) seems like good way to go. This is where I am left very confused, since I have no plumbing and little tapping experience.
What pipe tap will leave me with the proper threads to fit a 3/4 inch plug? There seems to be a difference in how inner and outer diameter are translated in this realm.

Maybe there is another, more simple and cheap way to do this?
Thank you guys in advance!

Get these.

Do this.

903hblue · #11 04-30-2017, 12:17 PM

Quote:

Originally Posted by tjts1

Get these.

Do this.

THANK YOU!

903hblue · #12 05-02-2017, 03:17 PM

I got an update for you guys. I figured out that a 1/2" knock out seal will fit directly into the manifold opening. I coated the edges with Permatex Ultra Copper Gasket Maker, then knocked it in with a dead blow hammer. Initially I thought I would still need to cover with the 1" knock out seal, then clamp everything, but the 1/2" seal seems to be holding very well. Of course if it gives way then I will resort to the clamp, but for now I'm enjoying the cleaner look of only the seal.
Thanks to all who helped!

tjts1 · #13 05-02-2017, 03:47 PM

Nice job, I'll try the 1/2" next time.

903hblue · #14 05-02-2017, 05:52 PM

Quote:

Originally Posted by tjts1

Nice job, I'll try the 1/2" next time.

Thank you!

ROLLGUY · #15 05-04-2017, 03:11 AM

Quote:

Originally Posted by 903hblue

Thank you, but it looks like that kit is designed for the om603. Once the mixer housing is removed on the om602 all that is left to plug is the hole in the exhaust manifold.

FYI, the kit works on all 61X & 60X engines except 606 and newer.