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EGR valve and hose DIY cleaning

CLK-Class (W208) 1998-2002: CLK 200, CLK 230K, CLK 320, CLK 430 [Coupes & Cabriolets]

EGR valve and hose DIY cleaning

Old 01-29-2015, 02:54 PM
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2012 E550 4matic TT
read procedure and challenges here. It may not be something for you to DIY; you have to remove the fuel injectors, coils, fuel rail, egr, throttle body, etc. to get the manifold off.

If you take it to a dealer, they will tell you the entire manifold must be replaced as MB says it is not a serviceable part. I believe an entire new manifold part is a little over $1k.

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Old 08-24-2015, 08:12 AM
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E55 AMG V8 Kompressor 2004 E 55 AMG Type: 5,439 cc (5.439 L; 331.9 cu in) Supercharged V8 Powe

Hi Guys,, nice write up..

Just to clarify P0400 is NOT just the one valve but means
Exhaust Gas Recirculation Flow Malfunction
bare in mind is can be anything from a bad/broken vacuum hose to sensor, pressure test vacuum system will reveal any leaks, or simply visual inspect the hoses.
Possible causes
* Plugged EGR passage which restricts the flow of exhaust gasses
* Faulty EGR solenoid Faulty EGR solenoid wiring/harness
* Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
* Faulty EGR valve
Actually just by removing the connection to the EGR solenoid with engine running will throw you the P0400 code, so..

Air filter intake on intake manifold simply pull/ push away from engine towards cabin using a hammer surely will brake it,, DONT use hammers EVER.
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flapjack (12-05-2017)
Old 03-07-2016, 01:22 AM
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BMW 2012 X3
Originally Posted by OGCLK320 View Post
Ok, so I just tackled this today, and really had very little knowledge about what to do. I basically researched on here and then went for it!

The EGR valve on the 320 motor is in the rear of the motor passenger side you can find pics on other threads that show location, not hard to find.

Now here is some quick background info, CEL light comes on last week and throws 4 codes at me, one of them being p0400 which is the egr valve, I cleared codes and nothing came back until a couple days ago after running my car hard on some canyon roads, I pulled the codes again and it was only p0400, so I figured since it returned after clearing last time, this must be the culprit, I did my research, and decided to go for it, because a local indy quoted me 500 for parts and labor, I opted to try it on my own, haha

The EGR valve itself is held on by two 10mm bolts, but the hose needs to be removed as well, two 8mm bolts. I had to remove a few hoses and also the intake in the rear near the exhaust manifold to be able to pull the actual egr hose out of the manifold, it goes in there about 3-5 inches and has a nice bend in it to make it as tricky as possible to get out.

After removing, I could not believe how plugged up the actual hose was the was in the manifold, as others have said, I nearly only had a pin hole of air moving through, it was ridiculous how clogged it was.

So after removing EGR cooler valve and hose I noticed all the hoses on the EGR valve had rotted away and the gaskets were no good either, made a quick trip to the dealer and bought the hoses and new gaskets $22. and some carb cleaner $5

Went home and started cleaning the crap out of the hose and valve, the valve had a little build up, but nothing compared to the hose, I used air and a clothes hangar, (metal obviously) to scrape all of the gunk out of the hose and valve, pretty much got them almost brand new looking... took about an hour to clean them up.

I then went ahead and started putting everything back together, slowly but surely I was able to get them back on properly,

Some little snags along the way, just had to move parts out of the way, a few hoses, and the intake was the main one for me to be able to remove the hose from the manifold.

It took me about 3-4 hours with clean up and test drive.

The difference was incredible, throttle response and how much quicker the motor revs up, I can only imagine how long this has been building up, it took way to long for the CEL to come on for this, because my car has felt sluggish for ever. I have 240k and I believe this stuff had never been touched before this morning.

I saved my self roughly 450 dollars and I know it was done correctly and efficiently. I would recommend everyone doing this them selves if you are a handy person and are having sluggish symptoms or receive the p0400 code.

I hope this helps a few people, I really wish I would have snapped pics but my hand were filthy and I just wanted to get it done.

A little patience and hard work will go a long ways!

Happy Holidays!
Very useful tips on EGR valve cleaning, needless to say lots of people will be educated.
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Old 05-19-2017, 03:33 PM
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98 clk 320
what kind of socket do i use to take off the 8mm and 10 mm bolts
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Old 12-05-2017, 03:32 PM
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Looks like E-torx, just like most of the other heads on these cars.
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Old 03-06-2019, 01:25 AM
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2002 CL500 to CL55 conversion
Originally Posted by jonUF02 View Post
Next step: take apart the entire intake manifold and clean it thoroughly. All that gunk that stops up the EGR tube was previously, and is now, going into your intake manifold. The manifold has big mechanical flaps inside that change the air flow as you accelerate, they are most likely really gummed up and may not even be moving to give you the maximum air flow. See my long thread about rough idle with pics.
i just wanted to add that mercedes recommends to never open the intake manifold. They consider it a “non serviceable” part

kind of a joke when you consider they also said the transmission is “sealed for life”. Which we all know is untrue, as all transmissions should have routine maintenance

but I will agree with mercedes somewhat about the intake manifold. I just started a diy thread(in 215 forums) about opening the intake manifold and let me tell you, this is about a 5 day DIY job to do properly. Most of the time spent waiting for sealant to cure, or letting the magnesium parts soak in gasoline to fully clean everything. Most DIY guys would rush this job I think, and the intake manifold is apparently notorious for having vacuum leak issues after people have opened them up

just wanted to add in case anybody came across this thread, because I did. You’ll surely gain a few horsepower back if you have a dirty manifold, but be prepared to re-do the sealant job/cleaning job until everything is perfect
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Old 03-06-2019, 01:33 PM
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2012 E550 4matic TT
I picked up a spare intake manifold at the local u-pull yard for maybe $50 or something. That way I had all the time I wanted to experiment with opening and cleaning it. Closing it back up is just a matter of silicone liquid gasket stuff, I'm not sure on the recommended cure time, but probably not more than 24hrs on that. Getting all the deposits cleaned off is a real tough job.
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Old 03-26-2019, 01:43 PM
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2001 CLK55 AMG, 2015 SRT392 Challenger
Originally Posted by AMG_BENZ View Post
I am wondering, is there a manual book for a CLK? Like the good old Bentley manual for a VW...

I am not sure if your problem can happen to 4.3L and 5.5L, but it's worth to keep that in mind.
Ahh yes! The Bentley manual was my bible when I owned a MkII GTI several years ago.
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