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.