Wednesday, April 29, 2015

Lubricating the Waste Tank Seals and Macerator

I was certain that I had written about this before, but searching this entire site I can find no mention of it. It is very important to regularly lubricate the tank seals in the black and grey tanks - and for those with Roadtreks or any RV with a macerator, the added benefit of the process is that it lubricates the internal parts of the macerator at the same time.

When we got our Roadtrek in 2011, the recommended lubrication to do this was coconut oil. Coconut oil is expensive and has a problem - it reacts to temperature. If you go to buy coconut oil - I found it in a gourmet food store - it is sold in a bottle as a white paste. At 75 degrees F coconut oil liquifies and becomes a clear liquid. Below 75 degrees F that same coconut oil becomes a solid fat - thus the white paste. I also found that the Camco RV supplies company sells "Coco Lube" which is a 100% coconut oil lube in a bottle. I bought that at over $6 in an RV shop. I bought it in the summer and tried it in the summer and it seemed to be fine. Then in the Fall I decided to lube the tanks again and now that bottle was full of white paste. I could have gotten it out of the bottle and put it down into the tanks but it would have been a gunk going down and likely would have staid in a lump in the tank. This is not at all what you want.

I started researching what the alternative is and learned that many use mineral oil. Mineral oil is sold in pharmacies or pharmacy departments. It is sold as a laxative - yes, it is "food grade" and can be consumed which you don't want to do unless you wish the resulting effect. You should be able to find a bottle for about $2 or $3.

To use the mineral oil to lubricate your waste tanks (and macerator):

1) Measure ONE HALF CUP of mineral oil, open the toilet flush flap and pour it down the toilet.

2) Flush the toilet with water.

3) Measure ONE HALF CUP of mineral oil, and pour it down the open drain of the kitchen sink. (Take the drain stopper out first.)

4) Run some water down the drain in the sink. 

You have just lubed your tanks and macerator. Step 1 and 2 put the oil into the Black Tank. Step 3 and 4 put the oil into the grey tank.  You are DONE.

Simple. You can't get more simple than this.

The mineral oil in the tanks will lubricate the seals in the tank. The next time you dump and use the macerator that mineral oil will come through into internal workings of the macerator and lubricate those also.

Do this two to three times each year. I do this AFTER I De-winterize. I do this Mid-summer. I do this in the Fall. This is all that is needed.

Just as an aside - always keep the flap in the RV toilet covered with water to prevent it from drying out. In the winter when winterizing, use RV antifreeze instead of water.

NEED I SAY THIS? Never put mineral oil into the FRESH WATER TANKS. It will not harm the tanks but like Eveready batteries, you will keep going, and going, and going...


  1. Thanks for this simple piece of maintenance advice!

  2. thank you very much for the information, I have been searching for a while