extending the slobber tube

First, refurbished means just that, the engine was refurbished, meaning rebuilt. It may have been the original engine (unlikely but possible just due to the time to have it done) or it was an engine rebuilt by a diesel rebuilder just waiting for a new home.

Second, a slobber tube does just that - slobber out a little oil and oil vapors that could look like light smoke. The smoke with oil vapors, unless extended, gets sucked into the front side of the radiator and blown through it sticking to the radiator fins which clog up with the dust and dirt also sucked through the radiator.

Third, your engine has always produced some smoky vapor. Whether it's excessive or not, only a good diesel shop will be able to tell you. Whether it's excessive or not you should still extend the tube so the oil vapors do not go into the radiator fins. Take it to a Freightliner shop and have them take a look at it.

Bill

Acceptable blow by can be measured by any authorized Caterpillar shop and you can extend the road draft tube (slobber tube) to any length you want and put it anywhere you want to.

Case in point, I deleted the blow by recirc system on my 7.3 Ford pickup and added a road draft tube and ran it down along the frame rail to a mid point under the truck.

Lots of levels concerning a 'refurbished' engine from just a minor rebuild to a full teardown. Obviously, you have no idea what was done.

#1 cause of excessive oil blow by is overfilled crankcase.

Have you verified that your oil level is correct? Caterpillar recommends not adding oil until level is down to the ADD mark.

And, on RV's, it is not uncommon for the dip stick to be mismarked, as the RV manufacturer supplies the dipstick. If yours is OE from Caterpillar, this should not be your problem.

As far as extending the blowby tube, it can be done, BUT (large BUT) there are some "got-yas". Water vapor is a natural byproduct of combustion and does exit through the blowby tube. So, it is important that the extension only go downhill/not have a drip loop. In sub-freezing temperatures, water vapor can collect and freeze in the drip loop and block air flow. A real no-no.

Here's my slobber tube extension (CAT 3126). As Brett stated, it's important to get a down bubble to let it drain. I re-adjusted the slope after taking this pic. Over the 11 week summer trip, I got no engine oil on the white toad (hydraulic fluid - yes, anti-freeze - yes, but no oil).

Why not install an Airsep system and be done with it?
Airsep