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Looking at a CRD....this is bad right?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=36236		 Page 1 of 1
Author:  deker [ Thu Sep 25, 2008 3:23 pm ]
Post subject:  Looking at a CRD....this is bad right?
So I've got a CRD from a dealer for an overnight test drive (LONG story....). Was listening for an extra rattle and my buddy thought it might be the engine cover rattling around, so he pulled the oil filler cap....then it was raining oil. Like, I put my hand over the oil filler and it came back black. This would be an indication of pretty severe blow-by no?

Thanks,

-d
Author:  cerich [ Thu Sep 25, 2008 3:30 pm ]
Post subject: 
no, oil in a CRD is black as black can be 20 minutes of running after a oil change.

the spitting out is the engines way of telling you to put cap back on..... :D
Author:  deker [ Thu Sep 25, 2008 3:47 pm ]
Post subject: 
I wasn't so much concerned about the color of the oil (as far as I'm concerned, black is good, that means the detergents are working and the carbon is being trapped in the oil where it belongs). My concern was that the pressure that's making the oil mist out is coming from???? I figured it was crankcase pressure making it into the valvetrain due to blowby. Am I missing something?

Thanks,

-d
Author:  Dawgbyte1975 [ Thu Sep 25, 2008 5:29 pm ]
Post subject: 
Mine has done this ever since I have had it. I've noticed it every time i've removed the oil with it running.
Author:  deker [ Thu Sep 25, 2008 5:57 pm ]
Post subject: 
Dawgbyte1975 wrote:
Mine has done this ever since I have had it. I've noticed it every time i've removed the oil with it running.


What kind of volume of oil do you see? This was pretty bad and may have had some exhaust smoke mixed in, I'll have to check again.

-d
Author:  tjkj2002 [ Thu Sep 25, 2008 6:35 pm ]
Post subject: 
deker wrote:
Dawgbyte1975 wrote:
Mine has done this ever since I have had it. I've noticed it every time i've removed the oil with it running.


What kind of volume of oil do you see? This was pretty bad and may have had some exhaust smoke mixed in, I'll have to check again.

-d
That would be crankcase pressure,perfectly normal and it is vented but diesels produce alot of it.If you ever see a older diesel running you will see some smoke coming from the breathers,in newer diesels it is vented back into the intake.Also a diesel has alot more oil pressure and it is getting shot everywhere inside of that engine(not the combustion chamber though,that would be a problem there) so if you open the engine(like take the oil fill cap off) you will have some shoot out,not always but that depends on where the oil cap is located and if it is baffled
Author:  UFO [ Thu Sep 25, 2008 6:36 pm ]
Post subject: 
deker wrote:
Dawgbyte1975 wrote:
Mine has done this ever since I have had it. I've noticed it every time i've removed the oil with it running.


What kind of volume of oil do you see? This was pretty bad and may have had some exhaust smoke mixed in, I'll have to check again.

-d
The checking of blowby is a common test for old Mercedes diesels. I am not sure what constitutes excess blowby in a CRD, however exhaust smoke is supposed to come out as that's what is creating the pressure.
Author:  Joe Romas [ Thu Sep 25, 2008 7:14 pm ]
Post subject: 
Unlike a gasoline engine that's crankcase is under a vacum the crankcase in most diesels are under slight pressure :shock: What you saw was perfectly normal of a CRD. My voice of experience is from the first day of ownership in 06 with a whole 9 miles on the clock and it's still the same 2 years later :D
Author:  deker [ Thu Sep 25, 2008 9:51 pm ]
Post subject: 
Gotcha. That's good to know as I continue to look...and I will be continuing to look. I tried to test out the 4wd on tihs one and it seems as if the selector handle is just not attached to anything. Add that to some other stuff missed by this dealer's mechanics before, plus the fact that it needed a new turbo at 53k, has a rattle in the front of the engine (though that's probably the alternator pulley)...I'll keep looking.

Thanks,

-d
Author:  Uffe [ Fri Sep 26, 2008 2:00 am ]
Post subject: 
deker wrote:
Gotcha. That's good to know as I continue to look...and I will be continuing to look. I tried to test out the 4wd on tihs one and it seems as if the selector handle is just not attached to anything. Add that to some other stuff missed by this dealer's mechanics before, plus the fact that it needed a new turbo at 53k, has a rattle in the front of the engine (though that's probably the alternator pulley)...I'll keep looking.

Thanks,

-d


New turbo, or just blown CAC hoses filled with oil from blowby causing a newbie diesel tech to change the turbo because he thinks a seal has broken? There's been plenty of mistreatments of the CRD on that account, as far as I can tell...

That blow-by is best handled by a catch can and some hoses going between the CCV to the catch can and back to the pre-turbo intake. It will blow about half a quart each 6,000 miles out that way, on my 03 anyroad...
Author:  cerich [ Fri Sep 26, 2008 9:13 am ]
Post subject: 
deker wrote:
Gotcha. That's good to know as I continue to look...and I will be continuing to look. I tried to test out the 4wd on tihs one and it seems as if the selector handle is just not attached to anything. Add that to some other stuff missed by this dealer's mechanics before, plus the fact that it needed a new turbo at 53k, has a rattle in the front of the engine (though that's probably the alternator pulley)...I'll keep looking.

Thanks,

-d



many have had the 4wd lever left not connected after the F37 on the TC is done. the rattle could actually also be the TC...
Author:  nursecosmo [ Fri Sep 26, 2008 8:27 pm ]
Post subject: 
The oil spitting out of the filler cap is not from blow-by. The filler hole is situated directly over the camshaft and there is no baffle. Contrary to popular belief the CRD engine does not have positive pressure in the crankcase. The CCV vents into the intake air stream between the air filter and the compressor. The air filter restriction induces a small amount of vacuum, which is just enough to pull the steam and oil vapor into the intake. The only way to check the amount of blow-by from the engine is to pull the CCV hose off and see what comes out. Know however that you will have an oily mess, and observing the amount of blow-by will probably not tell you much, seeing as how this engine makes a lot of blow-by until it is broken in somewhere around 50-100k miles.
Author:  deker [ Fri Sep 26, 2008 8:34 pm ]
Post subject: 
Well, the dealer called me again tonight...The general manager is the one I'm dealing with. According to his tech the pin holding the transfer case linkage fell out (pretty much as I figured). As he is still kissing my butt, I may give them one more shot when my wife gets back into town....This should be interesting.

-d
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