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Fuel questions

I thought I had asked this before, but maybe it was just on my list of questions to ask.

When we looked at the coach we're buying, it had about 1/3 tank of fuel of unknown age. The coach ran just fine on the short drive, but I'm wondering about the 300 or so miles home. I'm planning on filling the tank right away, and I'll fill it again when we get home. There are some spare filters in the coach, and I'm hoping that I'll be able to figure out which are fuel filters and which might be oil filters.

1. Should I get a biocide and add it to the fuel now, later, or both?
2. Should there be a problem, who might be the best to call? We still have Good Sam's until the end of the month (then we're switching to Coach-Net) so I'm assuming that they would eventually send out someone.

I'm not really expecting any problems, but since I'm new at diesel engines, I'd rather be prepared for a problem that doesn't show up than wonder what to do while sitting on the side of the road.

Re: Fuel questions

Reply #1 –
David,

The numbers will be on the side of the filters. If a different brand, just x-ref on the internet with the ones you have as spares. I generally run an additive like one on the list at: Lubricity Additive Study Results - Diesel Place : Chevrolet and GMC Diesel Truck

Our U300 had been sitting in a high humidity environment in N.C. without going anywhere for 2 years. Just installed new batteries, added about 125 gallons of diesel and drove across the U.S. visiting friends and National Parks.  Did lose the hydraulic belt a day after we left. Make sure you have an extra and adjust the steering wheel so you can see the warning lights above the speedo/tach.

Generally, you start to lose power on the hills as the first symptom of fuel starvation. If you do change filters, remember the little manual pump mounted on the frame below the air dryer on the right side in the engine compartment. All diesels don't like running out of fuel but Detroits are pretty tolerant.

Check coolant level as it will shut the engine computer down if low.

You didn't say if you have had an RV or large vehicle driving experience. Best to start in the morning and get home before dark if not acquainted with the vehicle.

Call one of us if you have a problem and are stuck. Write down the phone numbers in case you don't have internet by the side of the road.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Fuel questions

Reply #2 –
David, Keep spare filters and when you fill up use a clean oil jug ( a little oil won't hurt ) to get a gallon of fuel.  If you do clog a filter they are not too bad to change.Don't know what engine you have but on Cummins there should be two filters.  One is on the engine on the curbside up high and the other is probably on the side frame. Might double as a water separator.  Some coaches have a cut off valve to prevent fuel from running back to tank.  Close this valve, remove filter, see that filter base is clean and free of old O ring.  Fill filter with fuel, oil oil ring well and screw on, when filter is hand tight go a quarter turn more.  Start engine and run for a few minutes.  Then replace the other filter the same way. And as Pierce says give one of us a call if you get stuck on the road.
Good Luck
Gary B

Re: Fuel questions

Reply #3 –
First thing to do is to check for water in the fuel tank.
Look for a water fuel seperator, probably near the rear passenger side and check for water there.

Use the air level system to tilt the coach so that the front passenger corner is low (with the refer turned off), then leave it a few hours. Any water in the tank will move to the front passenger corner of the fuel tank. Siphon a gallon of diesel from the front passenger corner into a clear container and let it settle for a few hours. Any water will be visible. I do this every year just to be sure that there is no water in my tank.

If you find water, post another question about what to do on this web site.

If you do not find water, then drive to a service station and fill the tank. This will dilute the old diesel in the tank. My understanding of diesel is that it can be stored for years and still safely used. Others on this site may have more direct experience than myself.

Before you use biocide, you need to learn how to change the fuel filters and have several spare filters available. If not, you could be stuck on the side of the road with a plugged fuel filter.

 
Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Fuel questions

Reply #4 –
Thanks for the comments and advice. The engine is a Detroit 6V92.

My only experience with engine filters is dealing with the ones on our cars over the years. The oil filter was usually located in a hard-to-find place and usually required a blood donation while changing it. The fuel filter was generally an in-line one, usually located close to the carb. I haven't had to deal with one on a car in quite a few years, though, so don't know where they are hidden now that there are no carbs.

I'm assuming that somewhere in all of the boxes of information there will be something that says "oil filter number xxx" and "fuel filters numbers yyy and zzz." If not, the sellers may be able to tell me which is which.

Pierce, I'll put your phone number into my phone now. Thanks.

Re: Fuel questions

Reply #5 –
I don't think adding biocides can hurt
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Fuel questions

Reply #6 –
               I just went through the bad fuel issue. ISL losing power

        Fortunately I had listened to the smart folks on this forum and carry 2 sets of spare filters. Like pierce says, the first symptom was losing speed on hills, then the engine started cutting out for a second or two every few minutes. The check engine light came on and off. The engine never shut down and idled just fine but eventually I couldn't get up enough power to get out of 2nd gear.  I found a big clump of gell in the bottom of the secondary filter.

      To it's credit the Foretravel got us to our destination. We had a few folks blowing horns at us for slowing them down. ::)
              Not a fun thing to go through especially when your not really sure what the problem is.

                I would definately carry spare filters and a good fuel treatment. Changing the filters was not difficult but was a bit messy. A good strap wrench is neccessary too. I borrowed one from someone in the park after I broke the cheap one I bought at Autozone.

        I just filled the filters with diesel and installed them. Coach fired right up and took off like a rocket. Amazing what a little slug of water or gell can do to these beasts.
                                                    Good luck.

                            Dean
Dean & Deirdre

2012 Arctic Fox 22GQ
Was 2003 U270

Re: Fuel questions

Reply #7 –
I add Racor Biocide at every fuel fill. I had an algae issue a couple of years ago caught it at service time put on new filters, added Biocide then changed the water separator filter (the first filter your fuel line comes to) 500 miles later no more problems. Your Detroit will let you know(start losing power) when the filters start plugging up way before it just stops. Remember if you change your filters they only go on Hand Tight if they are over-tightened it can be a problem getting them off.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country

Re: Fuel questions

Reply #8 –
Thanks for all the good advice. We're heading to Bolivar this morning for some business and shopping (Wal-Mart always calls!), so while Jo Ann is getting groceries I'll see what they have for biocides. If they don't have any I'll try a truck stop another time.

Re: Fuel questions

Reply #9 –
Biocides are only needed if the coach is stored for an extended time in very warm conditions.  There is no need to add them regularly unless you have a surplus of cash.
Regards,
Brett

'99 42' Foretravel Xtreme
'14 Brown Motorsports Stacker
'05 Chevy SSR
'02 BMW R1150R

Re: Fuel questions

Reply #10 –
Quote from: amos.harrison –
Biocides are only needed if the coach is stored for an extended time in very warm conditions.  There is no need to add them regularly unless you have a surplus of cash.

I agree.  Unless you are storing the coach (3 months in winter/2 months in summer) you don't need a Biocide unless you have a known contamination issue.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Fuel questions

Reply #11 –
NAPA in town should have diesel Biocide or a west marine - RACOR is one brand, there are many
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Fuel questions

Reply #12 –
When you buy a diesel motorhome, it may have been sitting and not fueled for months. It could easily have a partial tank of summer diesel in the tank along with a bit of water at the bottom. While your engine will run on 100 year old diesel, the additives are not that stable and the fuel will go "out of spec" after a few months depending on temperatures. While our Foretravels (or at least mine) don't have an open vent to the atmosphere, it is still possible for moisture to collect on the inside walls of the tank and run down into the fuel. Algae grows on the interface between the water and fuel. Once it gets a foothold, it keeps on growing until all the water is removed or a biocide is introduced. A lot of RVs don't see year around use so they not only have a chance to grow some algae (if any algae is present) but the fuel may be the wrong fuel for your season and out of spec at the same time. I think it's a good idea to keep the recommended amount of a diesel conditioner like Opti-lube in the tank as well as adding some biocide before storage to keep the possibility of algae low. Here is what BP (British Petroleum) has to say about long term storage of diesel fuel: http://www.bp.com/liveassets/bp_internet/australia/corporate_australia/STAGING/local_assets/downloads_pdfs/f/Long_Term_Storage_ADF.pdf

Also see the Opti-lube site at: Opti-Lube Diesel Fuel Improver | Grease | Oil Fortifier 

When we shipped new cars from Germany to the U.S. and Japan, they were stationary for 30 days or so while on the ship. When we put gas in them, we included a generous dose of injection cleaner. Everyone immediately noticed a difference in how the cars ran after just a few miles. We generally delivered them to the EPA lab for the 3 bag testing so needed them as clean as possible. Not like your state smog test, as it cost $1000 for the lab to test each car. While diesel does not deteriorate as quickly as gasoline, extended storage will cause the fuel to go outside of it's specifications as the two links indicate.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Fuel questions

Reply #13 –
Quote from: wolfe10 –
I agree.  Unless you are storing the coach (3 months in winter/2 months in summer) you don't need a Biocide unless you have a known contamination issue.

I agree as well. Just to clarify I add it at every fueling but we make a lot of short trips 100mi or so in between fuelings, not so much when we are on the road. But with 1.25 oz per 100 gal I just figure it's part of doing business.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 1260 watts of solar on top
Moving around the country
 

Re: Fuel questions

Reply #14 –
Biocide testing article:  Sail Delmarva: Diesel and Biocides.  You need to know what kind of bug you have in order to know how to treat it.
1994 U225
build #4514