I probably get more emails on this subject than any other.
You must filter WVO no matter how clean it looks because, basically, it's full of crap!
One day I visited a small cafe in the hope of obtaining some WVO. I'd never been there before so when I asked the manager what she did with her waste vegetable oil, I steadied myself for the usual confusion that follows this question. But this lady was way ahead of me.
"You want to put it in your car?" she asked very casually.
I was amazed. Normally I have to go through the process of convincing people that yes, I really do run my car on it, no I'm not kidding, yes it's perfectly legal, etc. This lady had heard it all before and told me something very interesting.
"I used to have a guy come and collect my oil. He loved it because it's so clean. He poured it straight into his tank."
"Straight in?" I asked, genuinely shocked.
"Yes, straight in. My machine filters the oil as it comes out, so it's beautiful clean stuff. He used to come regularly but stopped a while back. I don't know why. Do you want it then?"
Of course I did. I collected a couple of containers she had around the back and true to form they looked nice and clean. The whole content was a golden colour and there was no sign of batter, crumbs, chips or any debris at all. It was clean.
So did I pour it straight into my tank? No way!
I let the containers sit on a shelf in my shed. You can see the pictures here.
After just one week of settling, the content had virtually halved into fats and useful WVO. Sure the oil was clean of debris, but animal fats, water and the like aren't immediately visible as they combine with the vegetable oil when hot. Over time these fats will separate and sink to the bottom. In this image you can clearly see these fats as the lighter coloured bottom half. The top half, after still more settling and filtering, went on to be used in my engine - but NOT the bottom half.
So why had the previous collector stopped coming for this useful commodity? Well I can't be certain, but I think I can guess...
If he poured the content of those containers into his fuel tank, all those fats and water would get sucked into his engine. I have no doubt that over time injectors would block, pumps would break and all manner of damage would be caused.
Perhaps he just got fed up of using WVO and stuck to diesel? Or perhaps his engine gave out and he got a costly repair bill. Perhaps even more frighteningly his engine failed whilst his was travelling down the motorway at high speed...
All I do know is that it's not worth it. Filtering my way is easy and cheap. Don't skimp on the process. You'll save a fortune and maybe even lives by doing it right.
“You can never do a kindness too soon” - Ralph Waldo Emerson
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