[manitoman]

I own a 2008 GC CRD and I still can't get my arms around why it is beneficial to add a catch can for the recirculated engine gasses. In retrospect, the part is inexpensive and if it is so important, why doesn't MB, make it part of ALL of their turbo diesel engines. Domestically the number of diesel engines is small, but globally it composes close to 40% of their engines.

Don't the exhast gases lubricate the turbo ?

will it void the warranty if I add the catch can ?

[fred99x]

The reason for the catch can is to filter the oil out the fumes being drawn into the turbo intake from the crankcase. There is a seal at the turbo intake that is prone to leaking oil onto the swirl motor and mechanism below the turbo intake. This leaking oil may cause the swirl motor to fail and possibly gum up the mechanism neither of which anyone wants. Installing this filter (catch can) will not void your warranty (according to my dealership) assuming a proper catch can is installed and properly installed. The exhaust gases drive the turbo but I don't believe they provide any lubrication. Not exactly sure how this turbo gets lubricated but maybe someone can provide this information.

[konarider94]

turbos are lubricated by the engine oil usually. there are oil lines under pressure that provide the oil for the hydrodynamic bearings that your turbine spins on. the bearing is actually a thin film of oil. additionally many turbos have coolant lines to help keep the housing cool.

[mitek]

That is a good question actually. Now that I have installed the updated intake hose with the new seal that stops the leak onto the swirl motor, I wonder if there is no potential damage from the factory design where oil fumes enter the air intake, should I still keep the catch can I had previously installed? The reason is that I don't really like all of this additional hardware and hoses under the hood which potentially can give you problems down the road. Just the other day one of the hoses got pinched and I lost a quart of oil through the dipstick release hole, good thing I noticed it right away and stopped to fix the problem.

[manitoman]

What is this "new seal that stops the leak into the swirl motor" ? Is this something that is covered under warranty? Again, my question is . . . with all of the MB diesel motors out there, why not include this catch can ? Why let the fumes get burned up if it's not a good thing and can lead to premature engine failure ?

[LJS8510]

Originally Posted by manitoman

What is this "new seal that stops the leak into the swirl motor" ?

http://www.jeepforum.com/forum/f67/crd-modified-intake-oil-leak-863459/

[nostaw22]

Originally Posted by mitek

That is a good question actually. Now that I have installed the updated intake hose with the new seal that stops the leak onto the swirl motor, I wonder if there is no potential damage from the factory design where oil fumes enter the air intake, should I still keep the catch can I had previously installed? The reason is that I don't really like all of this additional hardware and hoses under the hood which potentially can give you problems down the road. Just the other day one of the hoses got pinched and I lost a quart of oil through the dipstick release hole, good thing I noticed it right away and stopped to fix the problem.

Because of the high pressures of combustion some of the exhaust gasses leak past the piston rings and accumulate in the crank case which causes a pressure buildup if it isn't vented. The engine is designed to recirculate EGR (exhaust) and CC (crank-case) gasses back to the intake to reduce vehicle emissions and be environmentally friendly. This is standard on gasoline engines too...

On a diesel a little oil mist in the intake won't hurt anything -- diesel fuel is pretty close in composition to #2 heating oil, so A little engine oil in the mix won't matter - it will just burn with the fuel.

JW

[CRD_Joe]

Its called a ProVent. I have one on my CRD KJ. I know a guy who has one on my CRD WK as well. They work great. I wouldnt own a CRD/TDI without one.

http://www.cfpfilters.com/downloads/product_info/Mann/provent.pdf

[fatfreddy]

Originally Posted by nostaw22

Because of the high pressures of combustion some of the exhaust gasses leak past the piston rings and accumulate in the crank case which causes a pressure buildup if it isn't vented. The engine is designed to recirculate EGR (exhaust) and CC (crank-case) gasses back to the intake to reduce vehicle emissions and be environmentally friendly. This is standard on gasoline engines too...

On a diesel a little oil mist in the intake won't hurt anything -- diesel fuel is pretty close in composition to #2 heating oil, so A little engine oil in the mix won't matter - it will just burn with the fuel.

JW

I have read on other diesel forums that the oil mist you are talking about will collect in the intercooler thus causing it not to cool the intake air as well as it would if it were clean.It has been said that at around 60000 miles you have to take the intercooler off and clean it to keep it working efficiantly.So keep your catch can to keep the crap out of the intercooler and the rest of the intake tubes.

[Swayse]

I do it because of egr, exhaust gasses mixed with oil vapor makes a nasty mess in the intake. I vented mine to the atmosphere so I wouldn't get any oily vapor in the intake.

[nostaw22]

Originally Posted by fatfreddy

I have read on other diesel forums that the oil mist you are talking about will collect in the intercooler thus causing it not to cool the intake air as well as it would if it were clean.It has been said that at around 60000 miles you have to take the intercooler off and clean it to keep it working efficiantly.So keep your catch can to keep the crap out of the intercooler and the rest of the intake tubes.

Let me clarify.... I have read about the same issues with oil / soot buildup and I realize they can cause problems.

I didn't mean to suggest a catch can or CCV filter isn't a good idea too add. I just meant to clarify why ingesting a little oil isn't a problem if it doesn't cause fouling.

JW