Oil Change

Changing the oil may seem daunting with that big ‘ol diesel back there, but it is no harder than changing the oil on a passenger vehicle. There’s just a little, ok a lot, more of it. The steps are:

  • Warm up the engine
  • Drain the oil
  • Remove and replace the filter
  • Add the new oil

First off, it’s all a lot easier when there’s a little more room to maneuver. Some people get really excited about getting under there. If you’re concerned, the absolute safest way is to make large, solid wood ramps out of multiple layers of 2×12’s or similar and drive up on them. Of course we have these handy dandy hydraulic jacks already installed so why not use them? Bring it up a little in manual. Once again, some people get really concerned and you could put heavy stands under the chassis beams, or large constructed columns of pieces of wood 6×6’s or cement block. Personally, I have never heard of the hydraulics blowing out, and the odds of it happening are very small. There are literally thousands and thousands of motorhomes sitting on their levelers at this very moment and, again, I’ve never heard of one coming off them. So me, I’ll go under there for a few minutes just the way it is. To have the bottom of the oil pan nice and level I bring up the front a little too.

Warming up the engine is easy. Fire it up and run it at high(er) idle. Use the cruise control to control the RPM. After running for 10 minutes or so shut it down. Then, remove the oil plug in the bottom of the pan. It takes the square end of a 3/8″ drive. I use a cement mixing tub from Home Depot to catch the oil.


Once the oil has drained I put the plug back in and remove the tub. Now it’s time to remove the oil filter. That’s the round red thing in the picture….. It’s red only the first time because it was on the engine when it was painted. The new one is white. There’s a rubber O ring on there which tends to stick to the engine. Make sure you get it off as there’s a new one on the new filter. I put a small tub under there when I take it off, but as it is mounted vertical, right side up, there is little or no oil that comes out when you remove it.


As far as getting it off….. there are fora full of people lamenting that the first time the filter is a bear to get off. Not just our Freightliner chassis, same with the RAM truck people with the Cummins engines. Apparently there’s a gorilla in the Cummins factory assigned to putting on the filters that takes a lot of pride in his work……I am in the process of ordering a decent tool for it, and will update here when I get and test it. Meanwhile I used a LARGE channel locks with a wrench for leverage on it to grab the thing from the bottom.

Here’s another hot topic. Used to be it was nice to fill the new filter with clean oil before mounting as that would avoid the engine running without oil for a few seconds (bad). Today the manufacturers are talking out of both sides of their mouth a lot. Some places it says to put the filter on dry. The ECU (Engine Control Unit) will not allow fuel/starting until there’s oil pressure, so those few seconds of cranking until the oil filter fills and the pressure builds will not hurt it. What they say they DON’T want you to do is pour oil in the big hole into the filter as that is the “clean” side and oil out of a bottle (even new) is not considered clean (<25 micron instead of single digits. Hmmmmm.) To me then it follows that IF you want to fill the filter you plug the center hole (A thumb in a latex glove works well) and fill it through the outer ring with the small holes. (the “dirty side”). I now do just that.

Now lube the O ring with a little oil and on it goes. The diagram says to mount it finger tight plus one turn. I usually mount them as tight as I can with my bare hands. I’ve never had one leak, let alone come off. As far as which filter…..there are substitutes which are probably just as good. For as long as the warranty is valid I will use Cummins original parts, and I may stick with them afterwards. Takes the guess work out of it.

EDIT: I have since procured this little gem….. Sears Craftsman, available on line at Amazon. It does the trick and then some…..

EDIT EDIT: …. Currently not available…. but there are others like it.

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Now it’s time to put new oil in . The book specifies ASP rating of CJ-4 for engines with DEF. If you want to melt a forum or Facebook page start the “which oil to use” discussion. You’ll get 12 opinions from 10 different people. The consensus amongst owners of our chassis is that the Shell Rotella T4 15/40 is a decent oil for this engine. It’s not the only one, but it works for me. And it goes in the generator too. Wallymart generally has the best prices. 4-1/2 gallons. Yessir.

So, I put 4-1/4 in, which brings the oil about halfway up the range on the dipstick. Then I start the engine and run for 5 minutes. Shut it down, wait 10 minutes for the oil to settle and check/bring up to the full mark.

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There, done. Under an hour if you take your time. No traveling to a shop, and no paying $120+ materials for that hour.