Mercedes-Benz Forum banner

1 - 11 of 11 Posts

·
Registered
1995 E320 Wagon, 2002 S430
Joined
·
594 Posts
Discussion Starter #1
Need your help again guys, I Pulled two CEL codes - #5 and #9:

5 Exhaust gas recirculation inoperative
I have read on several posts that the fix here is to clean the EGR tube with a speedo cable/cordless drill combo. But I need to know where exactly this hose/tube is located and the procedure for removing it; then I will soak it in kerosen and try the roto rooter trick.

9 Intake air temp. sensor, open/short circuit
I need to know where this little bugger is located and any hints/tricks if there be any with replacing this. What will having this sensor fail do to the performance/fuel economy of the car?

Thanks in advance guys.
 

·
Registered
Joined
·
5,344 Posts
The EGR pipe goes from the EGR valve, on the right (passenger) rear of the engine, snakes around the behind the engine to the intake manifold on the left side of the engine closer to the front. You need to disconnect both ends to do a good job with it, and even then it's hard to get the snake to go all the way through. It's tough to get to on the intake side, 2 10mm bolts as I recall, the front one can be accessed from the top but the rear one is more easily accessed from below.

The air intake temp sensor goes into the air intake pipe somewhere near the air mass sensor, just before I think. Do an internet parts search and you can see what you're looking for. They rarely fail, just make sure it's hooked up, clear the code and you'll probably be fine, but it is cheap if you want to throw on a new one.
 

·
Registered
1995 E320 Wagon, 2002 S430
Joined
·
594 Posts
Discussion Starter #4 (Edited)
The EGR pipe goes from the EGR valve, on the right (passenger) rear of the engine, snakes around the behind the engine to the intake manifold on the left side of the engine closer to the front. You need to disconnect both ends to do a good job with it, and even then it's hard to get the snake to go all the way through. It's tough to get to on the intake side, 2 10mm bolts as I recall, the front one can be accessed from the top but the rear one is more easily accessed from below.

The air intake temp sensor goes into the air intake pipe somewhere near the air mass sensor, just before I think. Do an internet parts search and you can see what you're looking for. They rarely fail, just make sure it's hooked up, clear the code and you'll probably be fine, but it is cheap if you want to throw on a new one.
Deanyel, wow, thanks for the detailed and helpful response. The EGR tube removal and cleaning seems to be a bit of a pain yes? But probably well well worth it. I plan on doing it after some more important items like replacing the front rotors and pads (after learning you can't machine the rotors on MB cars). But I had a thought and please let me know if you think it is a good idea or not; that is...bypassing the old clogged EGR tube completely and running a new one (leaving the old one just sitting there) in a simplified more direct route from the EGR valve to it's native connection point on the intake manifold (what route exactly I do not know yet). If this was possible and recommended, what kind of tubing should be used and where can it be obtained? Why did Mercedes use stiff metal tubing? Would a professional grade NAPA cut same diameter high temp rubber flex tube be a suitable replacement? Or would the out-gassing of the rubber mess with the readings?

Oh, and I did locate the intake temp sensor, probably the easiest sensor on this car to replace (like taking a plug out the a socket in your home). Thanks for your help.
 

·
Registered
Joined
·
5,344 Posts
The original EGR tube, 104 140 02 08 was replaced with 104 140 05 08, a redesign that was less likely to clog, around $140 list. But the original wasn't that bad and replacing with the new requires removing the intake manifold, so a bigger job than just cleaning the old one. Buildling a new one would require fabricating the connection points which sounds like a pain, at least to do it well. It's difficult to snake the whole pipe from the valve side but if you remove both ends, and the mid-point bracket you can snake from both ends and get it pretty clean, at which point it should be good for another 50-100k miles. Remember to check for clogging at the intake side as well, where the pipe connects. It's a nuissance job but one or two cleanings probably covers the life of the car.

Mercedes brake rotors can be machined like anything else, just a matter of whether they are within spec when you're done. They recommend against it, most likley because they like selling new rotors. But new rotors aren't that expensive.
 

·
Registered
1988 M-BENZ 300E | 1991 FORD PROBE GT TURBO | 2003 FORD EXPLORER 4x4
Joined
·
684 Posts
BTW, how do you read the codes and where can I find the definitions for them.

I found the thing with the button and LED light.
 

·
Registered
1988 M-BENZ 300E | 1991 FORD PROBE GT TURBO | 2003 FORD EXPLORER 4x4
Joined
·
684 Posts
Ok, I'm having code 5 also.

Wonder if some SeaFoam in the intake will help.
 

·
Registered
1995 E320 Wagon, 2002 S430
Joined
·
594 Posts
Discussion Starter #9
Ok, I'm having code 5 also.

Wonder if some SeaFoam in the intake will help.
Not a bad idea but I think it would be very unlikely that a code 5 will be rectified by Seafoam. After seeing pictures of the gunk and buildup inside the EGR tube and given the fact folks struggle just to free SOME of it up with a high RPM roto rooter improvisation tells me that seafoam will merely take the dust off, nothing more.

I for one am not looking forward to taking that thing out, it's really snaked in there! But most everything else on this engine is meticulously well thought out and intuitively placed, easily accessible and serviceable. A true engineers dream. This car has been a real pleasure to work on these few days of ownership. I witnessed for the very first time last night the ingenious and unexpected washer fluid heating system (man these guys thought of EVERYTHING). Anyhow, getting way off topic now, but these cars really are worthy of the marvel and praise they receive -- this generation and prior. It's worth a 14 year wait, and a $45,000 drop in price! I still can't believe I acquired this machine for $2,900! Makes the CEL codes and repairs a minor inconvenience (a pleasure really as it gives me an excuse to work on the thing).
 

·
Registered
1995 E320 Wagon, 2002 S430
Joined
·
594 Posts
Discussion Starter #11
On a 1988 300E a code 5 is an oxygen sensor. Not a good idea to assume all code lists are the same.
Good point, hence another reason hijacking threads is not a good idea. As far as Seafoam fixing an oxygen sensor in this case...not gonna work. Get ready to spring for the part and do the replacement yourself.
 
1 - 11 of 11 Posts
Top