Clogged EGR Passages on ML 320 - PeachParts Mercedes-Benz Forum

sunedog · #1 11-18-2003, 03:21 PM

I have a 99 ML 320 with about 100K miles on it. The check engine light came on. I took it to my trusted independant mechanic and he reported the EGR passages are clogged. This delivers too much of the gases to cylinders 3 and 6 causing them to run rich (?) and triggering the check engine lamp.

He says he's repaired two other Mercedes engines with this problem. On one he had to remove the heads, on the other he didn't. He estimated repair bill at between $450 and $1800 depending on whether or not he had to remove the heads.

Is this common? Does it sound like he knows what he's doing? Is the repair estimate reasonable?

Thank you in advance.

sunedog · #2 11-19-2003, 08:53 AM

Update: Got the truck back yesterday. $1291 bill. Ouch. Here's the breakdown:

- clean out EGR passages: $232 labor and $30 parts
- R & R plugs and plug wires: $180 labor and $610 parts
- R & R battery: $0 labor and $142 parts
- shop supplies: $55
- tax: $42

So I got off lucky on the EGR passages. What killed me were the plugs and wires. The wires are $41 each. My mechanic said the plugs were worn to the point they caused the failure of the plug wires. He said 6 were definitely bad and 2 came apart when he pulled them off the plugs, so he went ahead and replaced all 12 wires. I won't complain about that decision.

Now I need to take it back in for the harmonic dampener pulley replacement and A service.

My jaw is clinched and I'm gritting my teeth as I smile and say "I love my Mercedes."

jbrowning73 · #3 11-19-2003, 10:50 PM

Did you have multiple problems? Was replaceing the plugs do to the milleage? If the only problem was a restricted EGR tube Why was he removing the plugs? Did you have a running problem too?

sunedog · #4 11-20-2003, 08:26 AM

Quote:

Originally posted by jbrowning73
Did you have multiple problems? Was replaceing the plugs do to the milleage? If the only problem was a restricted EGR tube Why was he removing the plugs? Did you have a running problem too?

The truck was idling a little rough, but my wife normally drives it and neither of us noticed the problem. I knew in the back of my head the plugs needed to be changed. The truck has just over 100K miles on it and the plugs were original. The mechanic said he was getting error codes on both problems with his diagnostic equipment.

sdanville · #5 12-16-2003, 11:17 AM

So, i like to try things on my own.
- anyone here Ever take their own EGR Tube off?
- I sure would like to see a picture of one and its location.
I was told the EGR on a ML320 is behind the right head.
I think I found it. but only a 2" rubber vacuum hose was attached as far as I could tell.
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anyone here Ever take their own EGR Tube off

Lebenz · #6 12-16-2003, 12:14 PM

It appears that most of the cost was for the R&R of the plugs, wires, and battery. Were any of these done before?

jbrowning73 · #7 12-16-2003, 07:14 PM

yes the egr valve sets at the rear corner of the right cylender head. You will see a steal tube that bolts to it that runs to the intake on the backside between the firewall. The tube is what plugs not the valve, you have to get the tube out and clean or replace it. You have to take the intake tube out to do this.

sdanville · #8 12-16-2003, 07:19 PM

Remove intake tube eh ?..-- Thats the part that air runs thru starting from the air filter box and runs back by the ERG ?

If so, I think I can do that.

I FINALLY found a Service Manual containing ML320 Information. This Chilton that may show me some pictures. Called Chilton SUV. the ML320 is only one of a dozens of SUV's listed , but with 2000 + pages it should help me.

I will order up shortly and dive in. I hope. Most likley ..I'LL BE BACK.
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December 22 2003 1st Day of Winter update. It is 40+ Degrees in Michigan so I took to my tools in the garage. With A cresent wrench and a metric socket set, in less than an hour I had the EGR Tube on my bench. I am not sure if it was 100% restricted , but cleand lots of gunk. Yet to test drive. Will update with results. Gilly gave me the info and encouragement to do the job. The intake tube was taken off to gain some room. I used a mirror and lots of light. I was elated the parts came apart as easy as if it were a Honda.
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December 23rd. Drove 20 miles. No more rough idle. I believe it to be cured! Thanks to Gilly's information.

sunedog · #9 12-17-2003, 11:04 AM

Quote:

Originally posted by Lebenz
It appears that most of the cost was for the R&R of the plugs, wires, and battery. Were any of these done before?

No. All were original and the truck had about 105K miles on it. They were due. I have no beef with the mechanic changing them. I just was floored when I heard I needed a set of plug wires that cost $504.

sdanville · #10 12-17-2003, 11:15 AM

$178 OEM ML320 Ignition Wire set online.
Disconnet one at a time..then connect.

You would have saved Hundreds.

ML320guy · #11 12-17-2003, 01:47 PM

can you provide more information on the plug wire process?

sdanville · #12 12-17-2003, 02:46 PM

I have not done it yet on the ML
I have done it on several previous cars and motorcycles.

Just replace them one at a time so they don't get mixed up.

I just ordered a Service Book yesterday that claims to have tune up information on the ML320.

check back with me in a week. It should be here. Maybe its trickier than I imagine.
sdanville@grar.com

Gilly · #13 12-17-2003, 05:19 PM

Nah, it's about the easiest set of plug wires you'll ever replace. The coils are on top of the valve cover (one per cylinder), dual plugs though, so a V6 has 12 of them. Can't hardly mix them up, just be a little careful. There is an upper and lower connector on each coil, the upper one goes to the FRONT plug. There are markings on the coil and the valve cover even, can't hardly go wrong.
My take on the situation is that you do need to be careful removing the wires from old plugs as has been discussed already, MB suggests using a wrench which was previously used by MB for adjusting valves, I believe on a M110 engine. Fits on the metal collar on the plug wire end and works just great. If one doesn't really have a clue on how to remove them properly, and just tries for example "yanking" on the wire itself, your gonna break wires. Possibly (I hate to accuse) the tech did wreck some of them, and instead of fessing up, recommended ALL of the wires. Maybe they wrecked ALL of the wires, I don't know, just conjecture here.

Gilly

sdanville · #14 12-18-2003, 08:29 AM

For months I have serched the World Wide Web for help on Mercedes ML320 maintenance. Turns out there is No place better than this sight and Gilly. Thank's for your unselfish time Gilly and being a good ol boy helping out us Mercedes owners without unlimited income. Mercedes may be out of my league if I had to pay the dealer for all the maintenance needed.
Rah Rah Rah .

As for the ignition wires. Everything else I owned you just yank off. So it is good to know don't yank. I thought I read..spark plug end..twist them 90 degrees left then pull.

Ron in SC · #15 12-18-2003, 08:44 AM

Steve,

You might want to use the search feature for this Forum. If you want to be a DIY'er you can find instuctions on may repairs including the spark plug change. If you don't want to take it to a qualified independent dealer or the MB dealer you will find that with the right instructions and tools may things can be repaired without much effort.