Everytime I drain the fuel filter under the truck, the fluid comes out green from the moment it starts draining.

1) If there is water in the bowl, does it completely separate from the diesel?

2) Is water heavier than diesel and would settle to the bottom of the bowl?

3) Thus if there is water, will it come out clear and then change to green?

Mostly use BP diesel fuel. Put on about 3,000 miles this year (trailer towing unit). I don't drain every month, sometimes it is several months.

 

hopefully nothing but if you have water, it will settle out to the bottom of the fuel. Drain the fuel into a glass jar and let it sit a few minutes but most times if you have any water, it will show up immediately.

 

Ditto to what Larry said. Better only see clean fuel. Whatever color you happen to pump. Green to clear...

 

I wondered about the same thing so one day after draining some diesel into a small mason jar I put a single drop of water into the diesel. It went right to the bottom and broke into some smaller drops but was very obvious.

Rob

 

I was just like you until yesterday. I have been draining my filter monthly since I fill up every week and never saw any hint of different fluids. Yesterday I drained the filter and in the bottom of my mason jar I saw 1 drop of water. It looked like an air bubble sitting at the bottom of green fuel. It separated from the fuel immediately and was very heavy in comparison.

 

Yeah ... surprised me a bit too, but the diesel fuel (at least where I buy it in South Texas) is alien green. I never see water so I took a clear clean milk bottle and put some fuel into it, then a bit of water. Obvious separation. I perform all of my own maintenance - I've never seen water in my system. I never perform a "drain only" ... maybe because it's so warm here? I only perform the fuel filter swaps. That reminds me .... it's time! Good luck!