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DonnaB · 10-26-2010, 11:38 PM

This is a heads up for others with 2007 Dutch Stars and might include 2006 and 2008 model years as well since the major coach design is the same in these model years. We have the standard 400 HP ISL Cummins engine on a Spartan chassis. We recently took our motor home into Cummins Northwest for a noise that was determined to be an exhaust leak. During the diagnostic process, they also found “several” oil leaks that were all covered under the Cummins engine warranty.

In fixing the oil leaks the tech found the oil breather tube was routed down the length of the valve cover to the rear of the engine (toward the front of the coach) then drops down. When Newmar put the coach on top of the chassis, there was not enough room engineered for proper clearance of this tube. The tube is a hard plastic of about ½ inch or more in diameter. There is only about ¼ inch clearance. This compresses the tube, but when the engine gets hot it would cause the tube to collapse. This causes back pressure in the engine which could have caused the oil leaks. We are lucky that Cummins did not deem this the cause of the leaks as they might have negated the engine warranty for this issue which would have been VERY expensive for us.

As part of the repair, Cummins re-routed our breather tube, putting a 90 degree elbow and running it down the side of the engine eliminating this problem. In addition, all the insulation and about ½ the material in the tube itself was worn away, as well as the fiberglass panel on the interior engine access panel (bedroom access point).

Just be aware of this especially if you have been having oil leak issues. Not sure if this would translate to other models with the same engine.

Route 66 · 10-27-2010, 04:39 AM

Uh oh!

Same rig, but no leaks.

Thanks!

soricobob · 10-27-2010, 06:25 AM

Excellent post, some very valuable information, and shame on Newmar!

Iron Man · 10-27-2010, 07:55 AM

I am wonderig if it only that floorplan or the 40 foot models? Did they do something different on other floorplans or the tag axle models?

Renden · 10-27-2010, 07:59 AM

No leaks

Thanks for the info

DonnaB · 10-27-2010, 09:26 AM

I don't really know about the floor plan issues or the tag. It has to do with how the coach box sits on the chassis and the clearances involved. However, if you pull off your bedroom engine access panel, it will be readily apparent if this is an issue with your coach.

And for those that say "no leaks".....we were not aware that we had an oil leak until we went in for the noise, so the leaks were fairly recent.

Ronnie Bledsoe 2006 Dutchstar 43' · 10-27-2010, 10:35 AM

I have 2006 43' (4306) with the same engine. Engine was removed 2 years ago for block replacement due to a block casting problem. The Cummins techs did not mention a problem of this nature.

jbilling · 10-30-2010, 05:52 AM

Great post and I can tell you from first hand experience it makes a BIG MESS. We have a 2007 Dutch Star 4320 with the 400. On our first trip to Florida with it we stopped in Knoxvillle for Fuel. Walked back to check our Tahoe behind and found the Tahoe and back of motorhome covered in oil. Engine comparment was a disaster. Luckily we had only lost about 2 quarts of oil but what a huge mess. The dispstick tube had melted about a 1/2-1/4" hole in it and pressure blew oil all over.

walkingplow · 10-31-2010, 11:04 AM

Interesting posts!! Had a similar problem as "jbilling" Cummins noticed the dip stick tube was melting - fixed it with a bonding tape and reinstalled it fastening it in a new location.