Hi diesel noob here again LOL....so I'm considering taking the plunge and buying my first diesel, 2015 Ram 3500 with 6.7L Cummins and 81k miles.Reading through the Diesel Supplement to the owner's manual, it says that if the "Water in Fuel" light comes on while driving, to stop immediately and drain both fuel filters, one of which is located under the truck. It occurs to me that that light is only going to come on when I'm dressed up taking DW somewhere...Do you drain the filters periodically to prevent the light from coming on? How often is that needed? If you're on the 8-lane bypass with traffic zipping by and the light comes on, do you pull over and shut 'er down?Thanks in advance!

With the Ford 7.3 mostly I just add some diesel fuel supplement, found in a white can available at any truck stop. It adsorbs water and removes it from the fuel through normal combustion.

Periodically drain the filter(s), that too should be in the manual. I have never had the warning and never saw any evidence of water in the drained fuel. I drain into a clear bottle, let it set for a day or more and nothing. Having said that, I better pack a jumpsuit.

There are two water in fuel(WIF) sensors. One on both filter units. It is recommended to pullover as soon as possible when the light comes on, but keep in mind that both filters are water/fuel separators so even if the primary filter under the bed fills up with water, it will take some time(many miles) to fill up the secondary filter up by the engine.The only time I had WIF sensor issues was when I accidentally twisted the wires when I performed a filter change. This exposed some of the wires causing the alarm to go off if I drove through a puddle of water and it splashed the exposed part of the wire harness. I changed the sensor/harness (about $35 online) and it never came on again in the past three or four years. You should not have to worry about this light if you change your fuel filters at their recommended intervals. Again, keep in mind that both are water/fuel filter separators and even if one is full of water, it has to fill up the second one before it gets to your engine which takes a long time and many miles. This is likely not going to happen quickly unless you have a massive amount of water in your tank which is dang near impossible.

If you get bad fuel you might get that warning. I bought my truck with 70K on the odometer and I've now put on 79K of my own. In nearly 5 years of ownership I've never had the WATER IN FUEL light come on. I've only ever touched the filters when I do my annual/15K mile oil change and fuel filter replacement.Some cheap insurance would be to keep a 10x10 tarp under the back seat and a small plastic cup if you have to do this in an emergency situation. The rear filter is directly over the drive shaft and when you drain it the fuel hits the shaft and goes everywhere. If you place a small cup under it you can catch the fuel and avoid a mess.Also, the front filter drains directly on top of the front axle. I attached a piece of 1/4" rubber hose to mine and routed it up by the radiator. This makes the outflow easier to see and also avoids a mess on your axle.KJ

5 years, 30K miles, never had an issue. Buy quality fuel from a busier station and you'll likely never have an issue. As others have said, you have the rear filter and front filter. Both have water collectors and drains. The Cummins has a great factory filtration system, I've never once worried about it.

Water in Fuel? When Do You Drain the Filter? | Good Sam Community

noteven
Explorer III
May 20, 2020
4x4ord wrote:
I think periodic fuel filter changes is a waste of time and money. If you get dirty fuel the new filter will plug almost immediately.... if the fuel you get is clean your filters will last for years. Some of my diesel engines haven't seen a filter change in 15 years. I change my fuel filters if I notice a lack of power or when the fuel restriction gauge shows a problem.

Don’t tell anyone but I was learned in Fleetguard filtration school that air filters need not be changed until the restriction indicator says to change. They do a better job of filtering as they load with dirt.
Grit_dog
Navigator
May 20, 2020
4x4ord wrote:
I think periodic fuel filter changes is a waste of time and money. If you get dirty fuel the new filter will plug almost immediately.... if the fuel you get is clean your filters will last for years. Some of my diesel engines haven't seen a filter change in 15 years. I change my fuel filters if I notice a lack of power or when the fuel restriction gauge shows a problem.

But your views on vehicle maintenance is THE reason more people buy new cars and are afraid of what they're getting in a used vehicle.

For the uninformed here, 4x basically buys a new vehicle, does the absolute minimum humanly possible to maintain it and then buys another new one before that one gets enough miles on it to have major problems due to lack of maintenance.

He's a used truck buyer's worst nightmare...
ppine
Explorer II
May 20, 2020
BurbMan,
You can pick up a load of water at any time. Like from the bottom of a gas tank that doesn't see much sales volume. If you see the light on the dash, by all means drain some fuel (and water) out of your fuel filter. Keeping the tank closer to full eliminates a lot of condensation in winter. Diesels are forgiving engines, but they don;t like water.
cummins2014
Explorer
May 20, 2020
4x4ord wrote:
I think periodic fuel filter changes is a waste of time and money. If you get dirty fuel the new filter will plug almost immediately.... if the fuel you get is clean your filters will last for years. Some of my diesel engines haven't seen a filter change in 15 years. I change my fuel filters if I notice a lack of power or when the fuel restriction gauge shows a problem.

I am kind of with you on this, although I do change this 2014 Ram of mine once a year, never had a fuel light come on yet, until the wires got chaffed on the rear fuel sensor on this Ram, and every time I would go thru a rainstorm I would get the warning ,new fuel sensor , no more warnings.

My previous 99 ford Superduty , got three fuel filter changes that I can remember in nearly 16 years. Never drained the filter ,never had a water in fuel warning. To this date 22 years with a diesel truck ,and never had a warning because of bad fuel. Lucky, no idea. Have bought diesel all over the western US , and parts of Canada.
4x4ord
Explorer III
May 20, 2020
I think periodic fuel filter changes is a waste of time and money. If you get dirty fuel the new filter will plug almost immediately.... if the fuel you get is clean your filters will last for years. Some of my diesel engines haven't seen a filter change in 15 years. I change my fuel filters if I notice a lack of power or when the fuel restriction gauge shows a problem.
ACZL
Explorer
May 19, 2020
Cummins12V98 wrote:
ACZL wrote:
Cummins12V98 wrote:
"I didn't drain the separator at last oil change and all is still well"

You better drain it today or you won't sleep tonight!

Wanna bet? It's 420am EST, 1st nite back to work and eyes are not doing so well staying open. LOL

Good to hear! Build America!!!

Sorry, my post was a tad misleading. Was on vaykay last week. My work has been deemed essential and having been w/ this place for close to 30 years, was pretty safe from getting laid-off. Did drop down to 4 day work week, but still goin'.
patperry2766
Explorer II
May 19, 2020
Cummins12V98 wrote:
Dennisokey wrote:
I have a 2018 Ram 2500, with it you replace both fuel filters every 15k. Go to www.Genosgarage.com for best prices on Oem filters. He does a great job explaining why you should no go with a non-oem filter on a diesel.

I like to support Geno's but the OE MOPAR filters are $85.80 on AMAZON Prime and Geno's Racor and Mopar are $108.42 with shipping of $10.52.

x2. There are some good videos on Youtube on doing it yourself. For S&G I asked at the dealership last time I was in how much to change them. Their quote was close to $300. Last change took less than an hour so I guess my time is worth $200 an hour. Wish my employer felt the same way
4x4ord
Explorer III
May 19, 2020
I've had a water in fuel light come on once. I pulled over immediately and drained the primary filter. If you get fuel with water in it there is no way of knowing how much water you got .... In the rare instances that a water in fuel light comes on I would recommend pulling over immediately. Draining your filter periodically is a waste of time in my opinion. If there is water in the filter bowl the light should be on. If there is no water in the bowl why are you draining it?
Cummins12V98
Explorer III
May 18, 2020
ACZL wrote:
Cummins12V98 wrote:
"I didn't drain the separator at last oil change and all is still well"

You better drain it today or you won't sleep tonight!

Wanna bet? It's 420am EST, 1st nite back to work and eyes are not doing so well staying open. LOL

Good to hear! Build America!!!
Cummins12V98
Explorer III
May 18, 2020
Dennisokey wrote:
I have a 2018 Ram 2500, with it you replace both fuel filters every 15k. Go to www.Genosgarage.com for best prices on Oem filters. He does a great job explaining why you should no go with a non-oem filter on a diesel.

I like to support Geno's but the OE MOPAR filters are $85.80 on AMAZON Prime and Geno's Racor and Mopar are $108.42 with shipping of $10.52.