Has your '96-'99 E300's intake clogged? - PeachParts Mercedes-Benz Forum

LightMan · #1 07-14-2003, 07:54 PM

Just curious, because I know they have EGR systems, and I know they have CCV recirculating systems. This combo makes for nasty intake clogging on VW TDI's. Wondering if anyone's had their intakes off and if they are dirty/clogged?? I saw one post of someone who disconnected the vaccum hose to the EGR on his '95 E300, and plugged the hose(off road use of course). Has anyone else taken preventative measures to keep the intake clean? Thanks,
Dave

#2 07-14-2003, 08:27 PM

What would a symptom of a clogged intake be? I don't have the resources to check myself and that is something I have not asked the dealer about.

LightMan · #3 07-14-2003, 08:59 PM

If your intake was clogging , you would slowly lose performance as your airflow through the chamber is reduced. Most likely it would be hard to notice as it's gradual. If you have your intake off, certainly look inside and see if it's gunked up, and clean it.

Here's a pic of a TDI intake after 40K with the stock EGR settings...

Rick Miley · #4 07-15-2003, 09:17 AM

The dealer cleaned mine at 75K miles when they had the intake off to replace the glow plugs. I didn't personally see it, so I can't say how bad it was clogged.

#5 07-15-2003, 10:48 AM

Don't ya'll both use biodiesel? Could this have anything to do with that TDI intake sludge? Not flaming--I have just been looking into the biodiesel scene lately, but don't want to create any extra problems.

JimSmith · #6 07-15-2003, 11:11 AM

narwhal,

I think that stuff is a product of blow-by oil vapors/droplets wetting the inside diameter of the intake manifold, and then having that relatively sticky surface exposed to exhaust particulate and smoke from the exhaust gas recirculation port. Unless you are suggesting biodiesel makes more soot I do not think using biodiesel is the problem. It is the concept of cycling exhaust through the intake, which is apparently something the engine doesn't like any more than your or I would.

Given an experience like the one Lightman has shown in the photo, and that these deposits are actually pretty common from other threads here, why is this practice still used? There must be some other way to control the formation of NOX, or what ever the EGR system controls in the emissions. Maybe if they took it off the downstream side of the catalyst in the later cars it would be hot enough to be effective, but not so full of junk!

It seems to me if the intake can plug up like that in such a short time there is a malfunction or design defect in the emissions equipment, which has a much longer warrantee than the rest of the typical car, like 100,000 miles or some such number. I would think a routine cleaning would be necessary to maintain the emissions equipment and that should be covered. Maybe if it started costing money an engineer would get the assignment to fix the problem and stop sending exhaust into the intake.

Jim

Rick Miley · #7 07-15-2003, 11:11 AM

No, that isn't because of Biodiesel, and I guarantee you that isn't Lightman's intake. His is clean as a whistle. Actually, the bio will create much less sludge than what you see there because it produces extremely little soot. There are rumors that bio can even help clean an already sooted intake.

Anyway, I cleaned mine in the Jetta a few months ago at 70K miles and it was not quite as bad as that picture. And, as stated above, I never saw the E300's intake. I just started using the biodiesel a couple weeks ago, so all my "intake experience" is petroleum diesel based.

Rick Miley · #8 07-15-2003, 11:20 AM

Jim was writing at the same time I was, so I want to post a followup. The real problem seems to be the diesel fuel that we use in the country. They don't have clogged intake problems in Europe where they're running low sulphur fuel. That should be taken care of in the U.S. by 2006 when low sulphur diesel fuel will be mandated.

Of course, the other half of problem is the crankcase ventlation back to the intake. If we didn't have to put up with this, then the dry soot from the EGR would pass right through and not stick. In 70K miles of driving, my Jetta "might" have vented a quart of oil if left open to the atmosphere. But because of the EPA mandated emissions controls, I ended up cleaning the intake manifold with 2 cans of carb cleaner, a half gallon of mineral spirits, 2 rolls of paper towels, and several pairs of latex gloves. Hmmm, I wonder which way is really better for the environment.

LightMan · #9 07-15-2003, 11:44 AM

Well folks, where to start. For one of course that's not my intake

Rick was right, mine is clean. However, mine is clean because I modified my EGR's duty cycle with engine diagnostic software at just 800 miles. This 'egr mod' has been very popular with the TDI community, in reducing intake clogging. The picture above is what happens to MOST stock TDI's after 44-60k miles. Those that run good fuel or drive higher rpms have slower clogging. I personally don't believe that biodiesel will clean your intake, but some claim that b100 use will. As posted above, the combination of the oil vapors/mist from the ccv and the sooty exhaust from the egr form the hard carbon in the intake. Using biodiesel or modifying the EGR/CCV are neccesary.

Not really sure what narwhal is saying, but I think he's asking/saying that the tdi intake clogging problem led me to wonder about the E300, and that assumption is correct. The last thing I want to have is a clogged E300. There is also a much much smaller crowd of E300 owners on discussion forums, than the 15,000 TDI owners on the tdiclub, so information and experience is much more limited.

I see on the left side of our engine, the ccv hose is easily accessible. It would be simple to attach a length of heater hose to the ccv, and run it to the ground, and cap off the hole to where it's re-routed... Also disconnecting and plugging the vacuum hose to the EGR will stop it, but my trigger a check engine light... These are a few of the things I'm curious about on the E300. Obviously if the intakes stay clean there's no need... Also folks modifying emissions equipment is for 'off road' use only

Edit: I finally see what narwhal was asking. NO, biodiesel causes NO intake sludge. It has no sulfur and relatively zero soot. The reason my intake is so clean is some 25,000 collective miles on 100% biodiesel, as well as a few tweaks

shoe · #10 07-15-2003, 02:21 PM

Is there any place that list where someone could by Biodiesel in the states?

LightMan · #11 07-15-2003, 02:33 PM

Biodiesel Distributors

Retail Fueling Sites

Keep in mind these are not always complete or up to date, but a good start!

lrg · #12 07-16-2003, 12:04 AM

For what it is worth, I believe the theory behind the EGR is that adding burnt gasses (exhaust) slows combustion and lowers the gas temps slightly which in turn reduces NOx production. NOx is largely a product of high temps at combustion.

michakaveli · #13 07-16-2003, 12:09 AM

Anyone know where the CCV line is on the non-turbo E300's? I wouldn't mind running a line to the ground to make sure non of the oil vapors keep entering my intake. This is the glue that makes the soot stick sooo well in the intakes. If the CEL comes on, just put it back to stock and after approx. 100 miles the lamp goes off. Worth a try :-)

LightMan · #14 07-16-2003, 09:28 AM

Quote:

Originally posted by lrg
For what it is worth, I believe the theory behind the EGR is that adding burnt gasses (exhaust) slows combustion and lowers the gas temps slightly which in turn reduces NOx production. NOx is largely a product of high temps at combustion.

No, actually the reduction in emissions is because the exhaust gas is burned again. EGT's are higher with EGR systems, because it's burning exhaust thats already hot, not fresh cool air. The EGT's however aren't a concern, its the sooty exhaust that the EGR recycles that might be clogging our intakes....

Rick Miley · #15 07-16-2003, 11:12 AM

michakaveli, venting the crankcase to the atmosphere will not cause a check engine light. That's not something that the computer monitors. Just look for a hose going from the valve cover to somewhere in the intake.