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Topic: Oil leak on Holset air compressor  (Read 471 times) previous topic - next topic

Oil leak on Holset air compressor

I've got a 97 C8.3 325hp 12 valve Cummins with a Holset SS296CE air compressor mounted to the engine. Stopped for lunch and noticed oil on toad, engine door and dripping below engine. Had topped off oil prior to starting down the road this morning.

Engine was down two quarts. Air pressure seems normal. Air is dry and clean at main tank. I'm going to keep on for two more hours to home base at The SKP Ranch near Artesia NM. Going to check oil along way.

Oil leak primarily at bottom of compressor.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Oil leak on holder air compressor

Reply #1 –
Sorry - I have no specific help with the leak.  Standard procedure would be clean up and dry the whole area around the compressor so you can see what's going on, then run the engine and watch for the source of the oil.  Once you know the source, the remedy should be obvious.  Hopefully, it is something simple like loose bolts or a blown gasket.  Good luck.


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Oil leak on holder air compressor

Reply #2 –
Found the posts below.  May offer some clues?

https://www.irv2.com/forums/f104/engine-oil-leak-air-compressor-hydraulic-pump-551672.html

https://www.irv2.com/forums/f123/oil-leak-on-rear-of-air-compressor-ideas-178891.html



1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Oil leak on holder air compressor

Reply #3 –
Did you ever change oil yourself. Dip stick may not adjusted for accuracy, which can only be done after adding correct # of quarts to an empty crankcase. Could the 2 quarts added be too much pushing oil out of breather/slobber hose vent from top of engine.

Re: Oil leak on holder air compressor

Reply #4 –
Changed oil and dip stick is accurate. Oil has about 3,000 miles on it. I will be cleaning every up tonight and then going for a drive tomorrow as suggested.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Oil leak on Holset air compressor

Reply #5 –
Ya, the second picture suggest a long-time leak and not with just fresh oil.
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

Re: Oil leak on Holset air compressor

Reply #6 –
Check the bolts on that triangular bracket at the end of the compressor.  The compressor is mounted on the rather fragile aluminum timing cover on the front of the engine.  The triangular bracket is there to help support the weight of the compressor, and to keep it from vibrating.  Posts on other forums mention the fact that if the bolts retaining this support bracket loosen or fall out, then the air compressor can start moving around, causing damage either to itself or to the aluminum timing cover.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Oil leak on Holset air compressor

Reply #7 –
Quote from: Realmccoy –
Changed oil and dip stick is accurate. Oil has about 3,000 miles on it. I will be cleaning every up tonight and then going for a drive tomorrow as suggested.

Remember someone posted a while back. When you have a new problem go and look back as to what you had just done.

Been wrong many time but, I am with Barry & Cindy. I would look and make sure the oil is not coming out your slobber tube.  I also agree with Wolfe that the leak around the air compressor has been leaking a long time and would be way wetter with the amount of oil you say has leaked out.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Oil leak on Holset air compressor

Reply #8 –
It may be the breather but the breather tube should exit near the level of the oil pan gasket,clean the tube and the screen in the valve cover,you may have excess crankcase pressure.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Oil leak on Holset air compressor

Reply #9 –
A little update. Cleaned the crud off and found the bolt on the back cover to be very loose. The other bolt was also loose. Tightened both bolts and will take it for a test drive tomorrow while refilling propane tank.

I also want to check the slobber tube. Can anyone describe the procedure for doing that? I found the valve cover outlet, a 90 degree tube coming from the valve cover with two hose clamps and a short rubber connection between the down draft tube assembly and the valve cover outlet that runs horizontally and then 90s towards the ground.

I also checked those mounting bolts and they were tight.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.

Re: Oil leak on Holset air compressor

Reply #10 –
I guess you could put a catch can at the end of the slobber tube.  I would clean the outside and best you can do the inside of the tube. After driving you can check and see if any fresh oil is dripping out of the tube.

After the drive home are you still full on the dip stick?

On my 1997 U295 the dip stick was off. It was full when the stick showed two quarts low.
2014 ih45  (4th Foretravel owned)
 1997 36' U295 Sold in 2020, owned for 19 years
  U240 36' Sold to insurance company after melting in garage fire
    33' Foretravel on Dodge Chassis  Sold very long time ago

Re: Oil leak on Holset air compressor

Reply #11 –
We monitor our tube by having it stuck 1/2 way down in a small peanut butter jar that has Stainless steel wool stuffed around the top. This leaves about 3/4 of the jar so you can inspect loss as the SSSW lets the vapors vent out.

Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Oil leak on Holset air compressor

Reply #12 –
I would take the tube off and clean out the inside and start from scratch,don't see any reason for "monitoring" a tube that is
not supposed to have the slightest restriction,if you do have oil coming out of the tube that's another problem.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Oil leak on Holset air compressor

Reply #13 –
Took the coach on a 70 mile run to get propane and check for leaks. Oil level unchanged , compressor was dry at back plate where bolts were tightened on the cover, and a small weeping of oil around oil pan gasket next to compressor. Next will be removing slobber tube to check for blockage.
Also plan to re-torque the pan gasket next. 

Thanks for the help! Running to Albuquerque on the 13th, then to OKC, Dallas, and back to New Mexico by Dec 10th. That will be the proof of the pudding.
1998 36 foot U270 Build No. 5328 WTFE, 900 watts solar, Victron controller, B2B, bat monitor, 600 AMPH lithium with 2018 Chevy Colorado toad, SKP #110239, Motorcade #17781, 2021 Escape 17B for when Coach is broken down and campsites are too small, retired and full-timer since Dec. 2020. Part of RV family since 1963.