Dirty Diesel

Most people report they have never had a problem with "dirty diesel." So, most likely neither will you.

However, there are exceptions to this rule. Some folks have reported "dirty diesel" problems ranging from poor performance and filter clogging causing a little inconvenience all the way to significant engine damage causing great delay and expense and even warranty denial if the rig is new.

The only way I know of to prevent getting a bad batch of diesel is to actually look at it before pumping it. I began doing this a few years ago. It takes an extra minute or two at the filling station, but for me it's worth it before pumping a few hundred bucks of potential problems into my tank.

To execute this low-tech approach, I have a gallon-size glass jar in my rig. After pulling up at the pump, I open the door where this jar is stored and pump a quart or so of diesel into it. If the diesel meets my approval, I proceed to fill my tank. About half way through the fill, I stop to pump another quart or so into the jar to make sure the fuel is still up to par.

I judge the diesel quality based on this simple criteria: The diesel must be clear, clean and bright, with usually a light golden or yellow tint. In cold weather, the diesel may be a bit hazy from the wax crystalization but this is acceptable and may prompt me to add some PowerService anti-gel compound to keep related problems away.

If the fuel is excessively old or dirty or has a lot of emulsified water mixed in it, it will be dark and hazy. If the fuel is contaminated with free water, there will be an obvious water bubble settling quickly on the bottom of the jar. All this fails my test.

When I encounte diesel that doesn't pass this test, I pay for the partial gallon and move on to more promising land and discard it later in an old oil bottle or two I keep with me for this purpose. It is not common to find problems, but it can happen. I've seen it myself.

I keep the the sample of my good downloaded fuel until I stop for the night just in case something might settle in the sample that I somehow missed at the station. Although this has never happened, I figure it doesn't hurt to keep it until I get a chance to pour it into my tank. A minor side benefit is that if I did miss something that only becomes obvious later, I have that sample to discuss with the station where I got the fuel for any appropriate redress of problems should they occur.

This process takes very little time but, for me, provides a lot of comfort way out there somewhere on the road.

I fuel up at the larger locations mostly, but on the back roads if I haven't planned far enough ahead. I don't carry extra filters (maybe I should), but I can change them. Knocking on wood.

Reading the labels is important but most of the time it does not give you a complete picture of what you are getting from the pump. I know that people on here will talk about the fuel mileage they got yet they have no idea how pure the fuel was when they filled up. Most labels, like ethanol and methanol, will list the MAXIMUM amount of ethanol as 10%. That means that it could be 10% or it could be 1%. I would guess that the bio-diesel is the same thing. You may have 30% or you may have less, depending on what was in the large storage tank when the new fuel was added. Without knowing the exact percentage of additives to the fuel, it is next to impossible to come up with an accurate fuel mileage figure.

In all the years we've been buying diesel for the motorhome, we have never had a problem with fuel. I always kept extra fuel filters but never needed them.

I always had the service shop use my fuel filters and then buy a new set from them to keep as extras. I didn't want to filters to become old.

About a month ago, I pulled into a truck stop in north Mississippi to get fuel. Filled up and then noticed the pump had a sticker that said something to the effect 'fuel contains up to 30% bio diesel'. WTH?

We have a sticker on our coach that says 5% max for bio diesel. I just made a trip to Nashville and back and filled up again at a Pilot putting in 85 gallons in our 230 gallon tank. The pump only said ULSD, no other stickers indicating bio diesel.

No lights came on in the last month with the larger portion of bio diesel or any notice of engine performance change. I'll keep a closer eye out for those stickers now.

MM.

I agree carrying spare filter is a good idea. Knowing how to change them is even better. If you don't know how to change them learn.

There are lots of mechanic that can change the filters for you if you get a bad load of fuel but they may not have the correct filter with them. Having the correct spare filters with you could get you going faster. Also knowing the correct filter number will help when you make the call to the mechanic so he can ensure that he has the filters when he arrives.

Old-Biscuit wrote:
7 yrs.traveling around USA
Rarely used any truck station (too dirty, too busy, too high cost)

We fueled at regular stations on secondary/backroads.......lots of times in very small towns.
Some name brand stations and some Mom/Pop stations


Never had an issue with dirty diesel

I agree with Old Biscuit - I fill up at a truck stop about one out of ten fill ups - usually when I sleep at one for a few hours. Their pricing is higher - us Gas Buddy. We can usually plan our fuel stops at Sam's Club or Fred Meyer's. We have to stop to buy food someplace and they usually have the cheapest diesel prices. We've bought a lot of fuel on the back roads and have never had a problem.

Bill

I don't know of any way to protect from loading bad diesel unless you have your own storage tank with good filters on it. However, your main protection is your primary fuel filter. It should have a clear bowl on the bottom of it you can look at daily when driving. In the clear bowl you can see water or contaminates filtering out if they're in your fuel tank. When more than a minor amount appears, drain it out and watch it a little closer for a while.

If your primary doesn't have a clear bowl on it, find a filter that does and change it out. On my Cat C7, I use either Cat or Freightliner/Alliance filters. I'll assume the same is available from Cummins. The filter and the clear bowl are sold separately as the clear bowl doesn't need to be changed very often. I do carry a spare bowl also as they become clouded over time and it's always possible to crack or break one.

You should have at least two sets of spare filters with you in case of contaminated fuel. And I'd tell you to have a third primary filter with you for standard maintenance when you have an oil change. Often the place changing the oil and filters won't have the correct filter on hand using a bowl because it's a little more expensive. When I stopped at Speedco for an oil change recently they didn't have a primary fuel filter to use a bowl with. I had to give them one of mine.

Bill

With many RVs only being driven a couple times a year I would bet that the fuel in your tank is worse than anything you are likely to purchase.

Old-Biscuit wrote:
7 yrs.traveling around USA
Rarely used any truck station (too dirty, too busy, too high cost)

We fueled at regular stations on secondary/backroads.......lots of times in very small towns.
Some name brand stations and some Mom/Pop stations


Never had an issue with dirty diesel

Ive had ONE in 15 years...and it dont matter where you buy fuel at.

7 yrs.traveling around USA
Rarely used any truck station (too dirty, too busy, too high cost)

We fueled at regular stations on secondary/backroads.......lots of times in very small towns.
Some name brand stations and some Mom/Pop stations


Never had an issue with dirty diesel