Have you cleaned out your intake lately?
 

You might want to do that.
http://i.imgur.com/sy291SB.jpg?1

http://i.imgur.com/C8X84rf.jpg?1

I pulled the intake manifold a couple of weeks ago to replace the glowplugs and noticed the intake ports and valves were filthy. I didn't have time to clean them so 2 weeks later the manifold came off again for cleaning. I used a couple of picks from HF but by far the best tool was a butter knife with the tip bent over 90 degrees to scrape out the grease. After scraping out as much as I could, I used some carb cleaned and a vacuum attached to a 1/4" hose to suck out the greasy liquid from the intake valves. I went through a large pack of paper towels and scraped out enough grease to make a couple of golf balls. The EGR was blocked off a year ago and crankcase vent has a catch can but I guess thats not enough to make the existing deposits magically disappear. Since cleaning it out the engine seems to build boost a lot quicker with less WOT smoke. I'm happy. I'm not sure about power since only had a chance to drive the car loaded.

That is totally disgusting. Thanks for the heads-up. :puke:

Was or is your car a wvo or WMO car?
With the diesel now produced as low sulphur I noticed a lot less carbon
and goop build up.
I also run a little cleaner about every 3 tanks.
My big truck has about 460,000 miles on it and it decently clean.
The Benz has about 150,000 and its really clean.
Just curious why some cars goop up and some don't?

As far as I know its always been run on straight diesel fuel. That was one of the reasons I bought this car, there were plenty problematic "veggi oil" conversion on CL I wanted to avoid. The engine consumers less than 1/2 a quart between oil changes a lot of which is an oil leak at the vac pump I still need to fix. The #14 head has never been removed so I guess its just 193,000 miles of blow by and EGR that nobody ever cleaned.

Duplicate post.

Fuel formulations and fuel system cleaners aren't going to clean or keep clean anything outside the combustion chamber and prechamber; i.e., anything in the OP's pictures.

Sixto
87 300D

EGR is the primary cause of this buildup. Deleting EGR should prevent it from recurring.

Although you'll feel better after cleaning, there will be basically zero improvement in power or fuel economy (unless one of the ports was drastically plugged up).

:boat:

Sixto is correct. Fuel cleaners won't keep a pre-CDI Mercedes diesel intake clean, as the diesel is injected into the prechamber, not above the valves as on gassers.

:stuart:

Doesn't the DI in CDI mean fuel is injected directly into the combustion chambers?

Sixto
87 300D

Yup - I believe that is correct. However since I've never worked on a CDI motor I wasn't sure exactly how the internals are set up. I think the CDI injects into the combustion chamber, without a prechamber. So fuel additives wouldn't help that intake tract either.

:chinese2:

Common-rail Direct Injection, I believe.

Even on gassers, additive would not make a large difference in keeping it clean... the injectors are typically located after the IM.

No, but URO is the OEM manufacturer for all EGR system parts.

Most of the Mercedes gas engines in the 80's and 90's have the injectors located above the intake valves. So in theory, fuel additives should help clean the intake valves.

You can pretty much achieve the same result by only using name-brand fuel that already has additives, i.e. Chevron, Shell, Exxon, Mobil, Sunoco, etc. The "cheap" fuel at no-name stations typically has much less, if any, additives and that's why it's cheaper. It's not worth saving the few cents per gallon, IMO, but that's a separate discussion.

:blink:

That is what my intake looks like on my OM602. I have a question regarding EGR... is disconnecting the vacuum supply to the valve sufficient to block EGR flow or do you need a shield between the valve and manifold?

This is a function of the EGR system and pcv system. Wifes '08 ML320CDI was that bad times 10 with 115k. Positive Crankcase Ventilation mixed with hot exhaust gas = crud. Problem would almost be livable if all it affected was the intake manifold; but the crud that accumulates on the intake ports of the head and the valves is what is really unacceptable.

Will be pulling my manifold in the coming weeks. for an inspection / cleaning. On the ML heads I basically scraped, sprayed and worked the goo out with my fingers while using a shop vac to suck it all out. The manifolds got sprayed with cleaner and power washed.

Oh, it would totally help the valves. I just don't see how it would help the manifold.

Depends on the year & model, and if your EGR valve is sealing properly when closed. There are a lot of threads on this topic, search the forum and ye shall find the answer...

:chinese2:

Exactly. It doesn't help the manifold at all.

:whistling2:

I finally had a chance to test out acceleration and the engine feels much stronger at the top end with almost no smoke past 4000rpm. Cleaning out the intake made a huge difference, more so than new injector nozzles or advanced timing. I should have cleaned it out earlier, well worth the effort. I need to find a good accelerometer app for my android so I can put some numbers on it.

The after numbers will be more telling with before numbers.

Sixto
87 300D

I cleaned the intake on my 617 as well, and blocked the EGR.

I used wooden sticks, plastic scrapers from Harbor Freight, brushes, cans of carb cleaner, diesel, etc. Wish I knew someone with a hot water pressure washer.

My 1997 E300D had 190K when I bought it. My manifold intake and air chambers were this bad and I cleaned them up and blocked off the EGR. This along with several other maintenance requirements got the car back to running like a champ.

The stickly crap in the air chambers was so bad and thick that I scrapped it out with a flat head screwdriver and I removed a ton of crap. What a dirty job, but it got done.

Pabster

Very true. Patoots are not known to be accurate performance meters.

:stuart:

Gasoline, compressed air and a lighter make quick work of that gunk!

HUMPTY BUMBDY OM606 edition
 

This is what came out of 1 of 12 intake runners in the cylinder head. A butter knife with a bent tip made short work of it. Its the consistency of axle grease.
http://i.imgur.com/g675fIi.jpg?1

I haven't even started on the manifold yet.
http://i.imgur.com/YBsE6xQ.jpg?1

The nice thing about the 606 is that it dumps its crankcase ventilation right at the point where the manifold meets the head so most of the manifold is not greasy like the 603 was. Once I scrape out the grease from the first inch or so, I can wash the soot out of the rest of it with my pressure washer.
http://i.imgur.com/Cf2iaH8.jpg?1

Ever since cleaning out the intake on the OM603 this catch can (re purposed high pressure air filter) does a great job of keeping the oil out of the intake.
http://i.imgur.com/1xiTW9Z.jpg?1

I'll be installing something similar on the 606.
http://i.imgur.com/86o5UGL.jpg?1

Instead of the idiotic 12 plastic crankcase vents they installed at the factory which are mostly cracked and broke.
http://i.imgur.com/SJ8SMkN.jpg?1

After cleaning out the manifold and ripping out the left over plastic chunks I plugged each hole with a short sheet metal screw then topped that off with some silicone sealant so no dirt can get in.
http://i.imgur.com/uNt6YHg.jpg?2

http://i.imgur.com/t6AEH2O.jpg?1

I capped off 1 of the 2 ports and ran a hose from the other between cyl 3 and 4.
http://i.imgur.com/llAGgHJ.jpg?1

The new oil/air separator sits on the right by the by the washer reservoir then the hose from there dumps into the intake snorkel before the air filter. This should keep the intake manifold clean for many years to come.
http://i.imgur.com/TNkfcMv.jpg?1

But the air oil seperator knocks out blow by. The issue of the black gunk is erg related. A 2 day soak in diesel fuel cleaned out mine with very little effort.

https://www.youtube.com/watch?v=3vOCwB2onGQ

I would bury it in sand or dirt to soak some of the heat away if there is any worry of heat warping.

Its the combination of EGR and oil that creates the black tar inside the manifold. The parts of the manifold that are only covered in EGR deposts are cleaned off easily with compressed air or the pressure washer. I blocked off the EGR a few months ago so thats not an issue anymore. The existing oil separator was clearly not doing a good job.

Prior owner did the EGR delete and manifold cleanout on my W210. It is still clean 18 months later.

I just did the EGR delete (thanks RollGuy) and cleanout with biodiesel (thanks Philly2tank) on my W124 and it subjectively seems peppier.

I suspect at some point I am going to have to face the dreaded oil cooler gasket change on my W164, and I am afraid of the crap I will find in the manifold on that vehicle.