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Topic: What is this? (plastic elbow in engine compartment) (Read 585 times) previous topic - next topic

What is this? (plastic elbow in engine compartment)

I'm doing engine clean up while the radiator and trans. cooler is out and came across a plastic elbow attached to a hose and the middle of the valve cover on the passenger side.  If it were on a car, it would be an EGR valve, but I'm not finding that in the archives.  Does anyone know what it is?  I need to replace the rubber grommet that is leaking oil.

[tweaked title to be more descriptive for future searches - Michelle]
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: What is this?

Reply #1 –
Guessing engine crankcase vent.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: What is this?

Reply #2 –
What some people call the slobber tube
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: What is this?

Reply #3 –
Try PCV positive crankcase ventilation in your search, not sure if your engine has one
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: What is this? (plastic elbow in engine compartment)

Reply #4 –
Quote from: rbark –
What some people call the slobber tube
It tuned out to be the road draft ("slobber") tube, after tracing through the oily build up, wires and other hoses.  I was surprised that it would come directly out of the valve cover - a little different from my  CAT.  I'm going to consider installing a recovery system (Racor); I installed one in my last diesel and it really cut down on oil vapors.  Now I just have to find the grommet.
Thanks Richard.
2000 U320 mid entry  #5688
2006 Jeep Liberty


USMCR retired
SDFD retired
FEMA US&R TF8

Re: What is this? (plastic elbow in engine compartment)

Reply #5 –
Sven, check the archives for containment systems other people have done here
Richard & Betty Bark & Keiko our Golden Doodle
2003 U320T 3820 PBDS
Build # 6215
MC # 16926
2016 Chevrolet Colorado 4X4 diesel

Re: What is this?

Reply #6 –
Quote from: Old phart phred –
Try PCV positive crankcase ventilation in your search, not sure if your engine has one
That is for engines with vacuum.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: What is this? (plastic elbow in engine compartment)

Reply #7 –
Quote from: craneman –
That is for engines with vacuum.
Even diesel engines have a small vacuum created by the air filter system. No free lunch.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: What is this? (plastic elbow in engine compartment)

Reply #8 –
I would do NOTHING that restricts the free flow from the crankcase vent hose-- certainly not a PVC valve. Even on the "pre-turbo" side of the intake system, you have less than 1/2 PSI vacuum (14 column inches of water). And, that only under full throttle.  Even less with a new air filter.

Sure, fit a catchment jug: old 2 quart juice plastic containers work well-- just cut enough holes so the exit holes you make near the top have a surface area greater than the ID of the hose.  Secure the container with the hose 3/4 of the way down into the container.

The oil vapor/water vapor pretty much collect in the bottom of the container.  If more than an ounce per 5,000 miles, you need to find the cause.  The most common cause is overfilling the crankcase.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020