If you have a CDI with 100k miles or more, you might want to check your EGR valve before there is an issue while driving.

My vehicle started exhibiting episodes where the turbo would go offline and the car would shift erratically and generally lack power. This happened infrequently but then more so. On my last 1200 mile trip, it happened at least three times. Once just after starting and accelerating quickly, full throttle and once on highway after putting around in city stop and go.

The issue would clear itself after turning car off and restarting. No CELs or warning lights were thrown. A MB tech. said when I was in for a fuel hose repairs that an EGR code was stored and he could read it on a Star machine. I had waited to ck. the issue out until it became more frequent.

After doing some research, I concluded the EGR valve was not working properly and found a post that indicated a cleaning would correct the situation at least for awhile. Several Sprinter forums also talked about clogged, impaired EGR valves as well.

Anyway, the EGR is made by Wahler and sits on top the engine under the cover on the driver's side in the back. It is held in place by two 10mm E10 external Torx bolts which also hold the oil dipstick bracket and a wiring harness in place. To remove the EGR valve, simply remove bolts and rotate the valve left and right. Once loose, lift straight up and away from engine. Mine was stubborn and I hit it with PB blaster and let it sit overnight. Came out easily next morning.

Cover or stuff hole with clean towel to keep anything from falling into engine manifold.

What I saw....The internal part of the valve was caked in some carbon but I do not think it was necessary to clean it. What was also caked and causing the binding was the armature/linkage that comes off the valve motor and operates the plunger portion of the valve. The plunger would get stuck while I manually operated the valve armature/linkage. The same no doubt happened when the vehicle is being driven.

You can inspect this by carefully removing the plastic cover on the valve even while the EGR is in the engine. I am going to start doing this at least every other oil change.

To clean the armature/linkage, it is probably best to remove the entire valve so you are not flushing black carbon and solvent all over your engine and perhaps a small amount back down the plunger into your engine. Remember to remove and reinstall the O-ring where the valve meets the manifold. If you carefully remove it, you should be able to reuse it.

I cleaned the assembly with brake cleaner and after drying, it operated with no binding. I applied a small amount of graphite to the arm and roller the arm goes around just to give a little more help.

In a pinch, you might be able to get the linkage working again on the side of a road by removing the plastic cover and vacuuming the inside. You can also flush it a bit while in place as there is a small drain hole oriented toward the bottom while it is mounted on the engine.

Here is picture showing inside with plastic cover removed:





Here is picture showing valve part that fits in engine:



What is interesting is that no CEL or warning light comes on. You just all of the sudden may have reduced power. From reading other people's situations, a CEL may come on after the situation persists for a length of time (repeated EGR problems).

MB will want to replace the EGR and perhaps reflash the ECU at a cost of +/-$800!! It makes sense in the make sure it is fixed world but I'm OK to do a little leg work and reuse a part that has just become impaired.

At 100k miles, coking with carbon of the engine EGR system is probable which can lead to EGR vqalve impairment. It makes sense to be proactive and avoid hassles or issues while operating the vehicle.

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

If one were to eliminate the EGR at the ECU for offroad testing purposes, would that eliminate the possibility of this occurring?

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Yes

However, I am not convinced that our CDI engines were designed to be operated without EGR technology. Does anyone have some research or source on the topic?

On older engines, EGRs were added to address pollution control. On the CDI engines, EGR may have been designed into them from the beginning. I do not know if there are any potential adverse issues with operating the engines with the EGR deleted.

What this cleaning process does do is restore the EGR valve to correct operating parameters. It does it economically too!

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

A cleaning once every 100k miles is not a good reason to disable the EGR. It was designed into the engine from the start, and if all it needs is a good scrub every decade it's far less troublesome than its predecessors.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

A good reason to disable the EGR is to keep diesel exhaust gasses, soot, and particulates out of our intake systems. Those particulates cannot be doing anything positive to the cylinder walls, valves, intake manifold, or oil.

I'm currently "offroad testing" my CDI with the EGR disabled. I'm anxious to see what the oil looks like after several thousand miles compared to the black color I saw previously in just a few hundred miles.

If chronometers EGR valve was caked with soot, one has to wonder what the rest of the intake tract looks like?

It's not just the EGR that's the issue....it's all the other stuff that gets gunked up by the exhaust.

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Ray don't be silly. The oil will be just as black as before. You drive a diesel, not a gas car.

The EGR is not hurting anything and it reducing the NOx your engine produces. Disabling it is silly, and shouldn't be done.

Again, cleaning once every decade is hardly a humongous deal. Do you know that the direct injected gasoline cars of today have to have their intakes removed and their intake valves walnut blasted to remove the Carbon build up off them? Standard maintenance on the new Mini Coopers...

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

Rest of intake that was visible was only lightly coated with dry hard carbon. EGR actuator seemed to accumulate more carbon perhaps because it was a terminal point?

Valve was made by Wahler of Germany. I know that there was a service bulletin on changing the EGR valves for early production EGRs but do not know if this one was an early version.

Agree, cleaning is easier and does not change design characteristics of engine. Until someone shows with hard evidence that an EGR delete enhances longevity, performance and mpg on vehicle and does not actually harm engine, I personally would not delete.

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

Believe what you want. I've been driving diesels for a lot of years. EGR issues on these cars is well documented. I'll choose to be silly then.

Very well. I agree with the OP that there is no need to break federal law and delete the EGR. Silly indeed.

__________________
'84 190D 2.2 5MT (Red/Palomino) Current car. Love it!
'85 190D 2.2 Auto *Cali* (Blue/Blue) *sold*
http://badges.fuelly.com/images/sig-us/302601.png
http://i959.photobucket.com/albums/a...0/sideview.png

I disabled the EGR on my OM611 car (same engine, only 4 cylinders) and it took ages to get warm from a cold start, and the MPGS actually went down.

I can believe that. I have read that the EGR system on the CDIs assists in warming the engine to operating temp. I note my CDI has reduced MPG during the warm up process according to the on board computer. Anything that would make the process longer, like lack of an EGR valve, would cut into fuel mileage.

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

I guess the question is whether you would rather have soot in your intake manifold or nitrous oxide in your lungs.

While I'm not generally a fan of additives, I decided to continue the Opti-lube regimen (boosts cetane and lubricity) that the PO used for the last 100k miles. It's cheap, it can only help, and one of the ways I suspect it will help is cleaner intake, EGR, etc....

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Nitrous Oxide in my lungs would sure make me a lot happier! And it would probably make my car run even faster! (But likely blow something up)

I think you mean nitrogen dioxide and nitric oxide, of which nitrogen dioxide is the really toxic stuff.

I tend to avoid directly inhaling my exhaust fumes.

I apologize to the OP for taking this thread off track. Good job to him for finding an issue and taking care of it himself. As well as a thank you for posting his process with pictures. Well done!