Black goo in crossover pipe - PeachParts Mercedes-Benz Forum

buffa98 · #1 11-15-2009, 05:25 PM

After reading another post I decided to pull my crossover pipe (from the turbo to intake). I found about a 1/4 inch build up of nasty black goo. Also, there was a small drool of oil laying on the top from where the up pipe comes up of the tubro into the crossover.
I scraped the goo off with a screwdriver and it has the consistency of cookie dough.
Some questions I have:
1. Do I need to pull the intake completely and clean it?
2. Do I pull the EGR or disable it?
3. Could this affect mileage? I run 60 miles a day to and from work (all highway) and some around town. Last tank I only got 25 mpg. Some folks say I should be pushing 30.
See pics attached.

Picture 1 - is that the waste gate?
Picture 2 - is that the EGR valve?
Picture 3 - this is the crossover pipe that I removed
Picture 4 - is the goo removed

Suggestions? Recommendations?

pawoSD · #2 11-15-2009, 05:27 PM

Picture 1 - Not sure, might be

Picture 2 - Yes, that is the EGR.

That gunk is from the EGR.....just disable (or remove and install block-off plate)

Cleaning the intake out might boost mileage, not sure about the EGR disable...maybe. It only helps the motor to disable it either way.

C Sean Watts · #3 11-15-2009, 05:48 PM

You should see the knuckle heads on you tube that use a blow torch to "clean" their intakes. Taking off the lower intake and cleaning it would not be a bad idea. If you have lots of cardboard and a place you can dirty up real good, use foaming oven cleaner on them. Have another car (trunk lined with garbage bags and more cardboard) and a change of clothes ready - after you use the oven cleaner go to a vending machine style spray off car wash. Be sure it's one that heats the water beforehand. Park WELL UPWIND. A $ or two will finish the job with rinse water to spare. I actually got down to shiny, clean aluminum. It also ran like a new engine. P.S. change clothes before you go back home.

In addition to the EGR in test mode, I have the PCV line in test mode and I'm evaluating that now. The oil cap does not get sucked down as before but it's not doing the tea pot dance either, it just kind of rattles a little bit. We'll most likely fab up some kind of oil separator since I was getting a lot of oil into the compressor intake elbow.

buffa98 · #4 11-15-2009, 09:26 PM

"In addition to the EGR in test mode, I have the PCV line in test mode and I'm evaluating that now. The oil cap does not get sucked down as before but it's not doing the tea pot dance either, it just kind of rattles a little bit. We'll most likely fab up some kind of oil separator since I was getting a lot of oil into the compressor intake elbow. "

By test mode do you mean that it is still on just not working? I am exempt from emissions testing BUT I still need to have the original parts on car. It also depends on who does the state inspection.

Please explain test mode, Also on your 300 does that have the same motor as mine? 603xxx

compress ignite · #5 11-16-2009, 12:32 AM

I've gotta disagree with Sean on this one...
Oven Cleaner is a Super "Base" (Opposite of Acid) Cleaner...

I will not recommend it's use when the possibility of "NON-COMPLETE" removal
exists.

"I ain't gonna trust my intake tract/engine to my ability to "Rinse" a BASE out
with a Carwash."

If you've got the Intake Off...
Take it to a Radiator shop and have it "Hot Tanked",problem solved.(Maybe $20.00 USD)

Ian White · #6 11-16-2009, 01:07 AM

Quote:

Originally Posted by compress ignite

I've gotta disagree with Sean on this one...
Oven Cleaner is a Super "Base" (Opposite of Acid) Cleaner...

I will not recommend it's use when the possibility of "NON-COMPLETE" removal
exists.

"I ain't gonna trust my intake tract/engine to my ability to "Rinse" a BASE out
with a Carwash."

If you've got the Intake Off...
Take it to a Radiator shop and have it "Hot Tanked",problem solved.(Maybe $20.00 USD)

I agree with Compress, simply removing the crossover and having it hot-tanked will get all the guk out from the knooks and crannies. I had my intake manifold "617" tanked for 10 bucks, looks like new too!

C Sean Watts · #7 11-16-2009, 09:44 AM

For a DIYer on a budget not wanting to go to a radiator shop (BTW if you find one who WILL do it - two turned me down when I showed them what I had.)

*clarification* IF the oven cleaner contains "sodium hydroxide, lye, soda lye, caustic soda, NaOH" or any other ingredient containing NaOH DO NOT use it. The key here is "foaming" oven cleaner. Many foaming ones on the market use potassium amines or "caustic potash" as the active ingredient instead of sodium hydroxide.

I should add- at the car wash use the hot, high pressure soap setting first and hold the intake parts down with your foot.
Since the intake is aluminum the main concern is not alkali but acidic cleaners. I do understand your concern but chemically speaking, they don't to the same thing to aluminum.

DO NOT USE DRAIN CLEANER (chemically classified as a strong base-usually NaOH or caustic soda lye) at all. DO NOT use oven cleaner (chemically classified as a weak base-usually some combination of potassium amines) IF YOU DO NOT USE SOME KIND OF HOT HIGH PRESSURE WASHER to clean it out. DO use some thought - wash and rinse it thoroughly and don't let it sit for more than 15 minutes or so. In the many times I've both seen it used and used it myself, I've seen oven cleaner etch one intake that was polished to a mirror finish, another polish and it was good as new.

AND, if you are worried about oven cleaner you should avoid radiator hot tanks just as much. Acid is a great way to remove the ceramic scale in a radiator but acidic hot tanks WILL etch aluminum. They are NOT just water.

C Sean Watts · #8 11-16-2009, 10:02 AM

Quote:

Originally Posted by buffa98

By test mode do you mean that it is still on just not working? I am exempt from emissions testing BUT I still need to have the original parts on car. It also depends on who does the state inspection.

Please explain test mode, Also on your 300 does that have the same motor as mine? 603xxx

On the 603, there is an oil separator in the valve cover. The black plastic elbow feeds crankcase vapor into the air intake elbow in front of the turbo compressor. On older engines, where the separator isn't working so well anymore, it also feeds a good amount liquid oil in. Pull your elbow off and check it. This also contributes to a soot filled intake (but not as much as the EGR.) The factory separator has a spring loaded mechanism in it instead of just a set of baffles and duct work like most others. It's also riveted in on the inside. It is still in place and not bypassed. I have to have the "in place" inspection in NC, also. What I have is the hose going into a vented catch can and not into the intake elbow upstream of the compressor intake. The intake is capped off during the testing so I do not draw in unfiltered air. What IS bypassed is that intake elbow. I'm testing how much oil comes out in a given time in order to gauge how big an external oil separator/catch can I'll need. ALSO there is a chance we'll plumb the oil back into the engine so we don't need to drain the can periodically.

If you loosen the oil cap and let it sit in place you can guess-timate the engine blow by according to how much the cap 'dances' like it's on a boiling tea pot. No dance = good. BUT, in the 603 the PVC hose elbow ends right by the cap so it gets sucked down by the intake vacuum. When you eliminate that intake vacuum, (remember - up stream of the turbo's compressor is the other end of that hose) the oil cap will not get sucked down. You'll also get a much better indication of blow by. I've seen a few gas and diesel, you actually had to hold the oil cap down to keep it from flying off.

GIFritz · #9 11-16-2009, 11:10 AM

How do you disable the EGR? Pulled my intake the other day to diagnose a glow plug issue and also found a fair amount of black goo in the intake and cross-over pipe. I have a 1990 350SDL with the 603.970 motor.

compu_85 · #10 11-16-2009, 11:38 AM

Disabling the EGR is illegal and can get you in biggggg trouble! You need to ensure that the single vacuum line going to the EGR valve is connected and not blocked with a screw or bb. The computer on the 350 has no way if knowing if the EGR is working. so it's your job to be sure it is.

-Jason

buffa98 · #11 11-16-2009, 01:11 PM

Disabling the EGR is illegal and can get you in biggggg trouble! You need to ensure that the single vacuum line going to the EGR valve is connected and not blocked with a screw or bb.

I am not trying to start a debate on the "LEGALITY" of doing anything.. I am only trying to find out if some one else has had this problem and how they fixed it, And how to prevent the repeat in the future...

PS It is also illegal to drive faster than the posted speed limit

but lets not go there. Deal?

hey_allen · #12 11-17-2009, 05:25 AM

Quote:

Originally Posted by compu_85

Disabling the EGR is illegal and can get you in biggggg trouble! You need to ensure that the single vacuum line going to the EGR valve is connected and not blocked with a screw or bb. The computer on the 350 has no way if knowing if the EGR is working. so it's your job to be sure it is.

-Jason

Read it again...

I'm not quite sure just how so many of our cars manage to ingest bb's in the EGR control plumbing. Must be a factory defect in the EGR system. Such a shame that MB doesn't pursue such obvious defects once the cars are a little old...

bustedbenz · #13 11-17-2009, 08:45 AM

Quote:

Originally Posted by compu_85

Disabling the EGR is illegal and can get you in biggggg trouble! You need to ensure that the single vacuum line going to the EGR valve is connected and not blocked with a screw or bb. The computer on the 350 has no way if knowing if the EGR is working. so it's your job to be sure it is.

-Jason

They'd have to know there was supposed to be an EGR where my large absence of one is.

C Sean Watts · #14 11-17-2009, 10:02 AM

Quote:

Originally Posted by bustedbenz

They'd have to know there was supposed to be an EGR where my large absence of one is.

A friend of mine had a can full of fuel left right after he sold is most recent diesel and he wanted to give it to me but keep the can - no problem. Ah, but it was red as high school prom punch....."No biggie, I'll just top it off when I get home, that'll dilute it down." Silly me, my inspection sticker expired two weeks after that. During which the mechanic was curious to see under the hood. He looked at the clear (red) pre-filter, looked up at me, chuckled, closed the hood and put the new sticker on my windshield. That was three years ago. Most of them would not have a clue, especially if I had to make an EGR gasket out of sheet steel and I forgot to cut the hole in the middle.

bgiovan · #15 01-31-2010, 11:04 PM

Can someone shoot a picture of what a missing EGR might look like under the hood and what was used in its place? Like if you saw one at a junkyard and snapped a picture of it? ;-)