Do Diesel RVs Really Need Fuel Additives for Maintenance and Longevity?

[kdmccarthy46]

We have a 2015 Tiffin Allegro Open Road Red (diesel pusher) and have had many great trips across the country and up into Alaska. Recently a fellow RVer suggested that we use a fuel additive to keep the fuel system clean and functioning optimally.

Thoughts on the use of fuel additives for RV diesel engines would be greatly appreciated as well as specific brands if recommending a fuel additive.

Thanks
Ken

 

[Joezeppy]

The only thing I use in my truck is anti-gel for cold weather.

 

[CharlesinGA]

There are a number of different fuel additives the diesel truck people use. You have a Cummins 6.7L common rail diesel and one of the more popular and well regarded fuel additives is made by Power Service Diesel. It is approved by Cummins to not harm the fuel system. There are several variations of it depending on the climate you are operating in and I'll leave it to you to read up on the various versions and make a decision on what suits you best. This is a popular additive.

Many people also swear by Hotshot's Secret additives.

Charles

 

[UTTransplant]

If you don’t put a lot of miles on your coach, then an additive might make sense especially in a humid climate where nasties might grow in your fuel. A cold-weather additive also makes sense if you didn’t fill up with winterized fuel. We have over 100,000 miles on our 2018 RED, and we have only used a winterizing Power Service additive when needed. Cummins doesn’t recommend routine additive usage for our engines.

 

[RayIN]

You might find this ISO diesel fuel additive study informative: https://www.dieselplace.com/threads/lubricity-additive-study-results.177728/
However it was a lubricity test study.
FWIW, the best fuel system cleaner is biodiesel. This is an excerpt from https://www.energy.gov/sites/default/files/2021-11/EnergySavers_Biodiesel_Factsheet-v2.pdf

"Are there any downsides to using biodiesel?
Studies of B20 and lower-level blends in approved engines have not shown any negative long-term effects. However,
biodiesel has a solvent effect. It cleans your vehicle’s fuel system but could release deposits accumulated from previous
diesel fuel use.
The release of deposits may initially clog filters, so users should check for and replace clogged fuel flters. Once the
build-up is eliminated, user should return to their regular replacement schedule. This issue is less common with B20 and lower-level blends."

 

[Tom]

We have a 2015 Tiffin Allegro Open Road Red (diesel pusher) and have had many great trips across the country and up into Alaska. Recently a fellow RVer suggested that we use a fuel additive to keep the fuel system clean and functioning optimally.

Thoughts on the use of fuel additives for RV diesel engines would be greatly appreciated as well as specific brands if recommending a fuel additive.

Thanks
Ken

Biocide helps keep algae at bay, which prevents fuel filters from clogging. Biogard is one of several brands I've used. You can also search this forum on biocide for prior threads and suggestions.

 

[Gary RV_Wizard]

Our coach was kept in a warm, humid climate (Florida) when not on the road, so I added a biocide (Biobor JF) to prevent algae growth during long storage periods. If I had lived in a cold climate, I would probably have used a anti-gel additive in case I needed to run the engine in the winter.

As for "keeping the fuel system clean & functional, I never found the need. I think the main purpose of that sort of additive is to prevent the build-up of cash in the owners wallet.

 

[Gr8bawana]

There are a number of different fuel additives the diesel truck people use. You have a Cummins 6.7L common rail diesel and one of the more popular and well regarded fuel additives is made by Power Service Diesel. It is approved by Cummins to not harm the fuel system. There are several variations of it depending on the climate you are operating in and I'll leave it to you to read up on the various versions and make a decision on what suits you best. This is a popular additive.

Many people also swear by Hotshot's Secret additives.

Charles

To use a product because it causes no harm is far from a reason to use it if it actually doesn't do anything for you.
When I see people swear by such and such fuel or oil additive they have ZERO proof that it actually works. They simply BELIEVE it works.

 

[CharlesinGA]

Some of the new additives actually do provide lubrication to the fuel systems. Diesel used to have sulfur in it which is an excellent fuel system lubricant. That's why the old systems always seemed to work OK. With the introduction of low sulfur diesel, (in 2006 in North America) the newer high pressure fuel pumps and common rail electronic injection systems need help to keep them functioning. Something the older systems didn't need.

Common rail fuel injection was introduced by Cummins in 2002 on most of their engines, and on the engines going into RAM trucks in 2003. GM introduced the common rail fuel injection system with the new Duramax engine in 2001.

The Ford 6.7L diesel has the notorious Bosch CP4 fuel pump. These have plungers with rather tiny rollers on the bottom running on a steep cam. (the CP4 was also used on Duramax and Cummins for certain year models, but it is now only used on the Ford 6.7L... and some small European diesels). The CP4 is fuel lubricated, and a failure of the rollers on the bottom of the plungers contaminates the entire fuel system, costing over $15,000 to repair, as everything must be replaced, from the tank to the injectors.

Dave's Auto Center in Centerville Utah did a video (actually several) where they tore down a 2011 Ford 6.7L that has been run since 50K miles, as a Hotshot hauler. The engine at the time of the teardown had over 900K miles on it, and the original CP4 pump. The owner said he attributed the long life of the pump to three things. 1) He only bought fuel at truck stops where they flowed large volumes of it, 2) he used a fuel additive (and he never did say which one) at every fill up. The pump basically looked like new inside.(and probably belongs in a museum somewhere) and 3) He also had additional fuel filters, over and above the factory filter, and said he changed them at every oil change.

900K mile CP4 Fuel Pump teardown video

Charles

 

[Gary RV_Wizard]

Charles is accurate (as usual), but he doesn't mention that oil refineries add lubricatives to low-sulfur diesel fuel as may be needed to meet ASTM D975, the USA national standard for diesel fuels. ASTM D975 specifies 13 parameters (tests) and all the major brands of on-highway diesel conform to the standard. However, there may be off-brands that do not fully comply, or they only comply with less variants of D975, e.g. off-road use, auxiliary power (e.g."refer fuel"), etc. There are 6 grades of diesel other than on-highway use.

I think it's fair to say that the old higher sulfur highway diesel had a lot of lubricity, whereas the newer stuff sets a lower amount as the minimum standard. So if you own an engine that is known to have barely adequate injection pump lubrication, using a higher lubricity fuel might avoid a costly repair. Biodiesel blends naturally have much higher lubricity than pure petroleum (aka dinosaur diesel), so a B10 or B20 blend may be of value. Or an additive that gives similar improvement,

 

[Gr8bawana]

Some of the new additives actually do provide lubrication to the fuel systems. Diesel used to have sulfur in it which is an excellent fuel system lubricant. That's why the old systems always seemed to work OK. With the introduction of low sulfur diesel, (in 2006 in North America) the newer high pressure fuel pumps and common rail electronic injection systems need help to keep them functioning. Something the older systems didn't need.

Common rail fuel injection was introduced by Cummins in 2002 on most of their engines, and on the engines going into RAM trucks in 2003. GM introduced the common rail fuel injection system with the new Duramax engine in 2001.

The Ford 6.7L diesel has the notorious Bosch CP4 fuel pump. These have plungers with rather tiny rollers on the bottom running on a steep cam. (the CP4 was also used on Duramax and Cummins for certain year models, but it is now only used on the Ford 6.7L... and some small European diesels). The CP4 is fuel lubricated, and a failure of the rollers on the bottom of the plungers contaminates the entire fuel system, costing over $15,000 to repair, as everything must be replaced, from the tank to the injectors.

Dave's Auto Center in Centerville Utah did a video (actually several) where they tore down a 2011 Ford 6.7L that has been run since 50K miles, as a Hotshot hauler. The engine at the time of the teardown had over 900K miles on it, and the original CP4 pump. The owner said he attributed the long life of the pump to three things. 1) He only bought fuel at truck stops where they flowed large volumes of it, 2) he used a fuel additive (and he never did say which one) at every fill up. The pump basically looked like new inside.(and probably belongs in a museum somewhere) and 3) He also had additional fuel filters, over and above the factory filter, and said he changed them at every oil change.

900K mile CP4 Fuel Pump teardown video

Charles

The problem with the Dave's auto story is that there is ZERO proof that the additive did anything. He may have gotten the exact same results by not using any additives. There is no way to know.
There is no way I would waste my hard earned $$ on a product that might work.
There are multiple people on diesel forums that have super high mileage trucks that have never used any additives at all.

 

[Derby6]

I don’t think most big truck fleets use additives. Drivers fuel and go. My 2019 diesel pick up has 204k and still going. No additives.
I used additives in my old ‘97 power stroke because all the talk of newer ULSD didn’t have enough lubricant. New ones designed for USLD.

If it sits and your worried about algae. That’s different. If your full of summer fuel and headed into extreme cold and need to add anti gel. That’s different too. That happened to me in my 2019. Lesson learned I’ll remember when I leave NV/ AZ to drive home this time— Fill minimal southern fuel and pack her tight with north winter fuel in Montana.

 

[Lou Schneider]

My 1999 7.3 Powerstroke has 250k and I never use any additives. No fuel system problems so far although I do change the fuel filter regularly.

When I was maintaining diesel generators at the radio stations (50kw to 250kw) we polished the diesel annually on the 5000 gallon tank feeding the 250 kw generator (it was good for about a month of run time) but never used any additives. The smaller generators had smaller tanks which were refilled frequently enough that algae and debris in the tank wasn't a major problem and the stock fuel filters were sufficient.

Polishing diesel fuel is running the tank contents through a series of successively smaller filters to remove algae and other debris from the tanks. Widely used in fixed and marine applications.

 

[workinonit]

I have used this stuff for years in my 1000 gallon farm fuel tank. I add a jug everytime I fill it up and never had any issues with algae. I also use a 10, 5 and 2 micron filter bank. A tank of 1000 gallons lasts me about 2 to 3 years.

 

[Gary RV_Wizard]

I have used this stuff for years in my 1000 gallon farm fuel tank. I add a jug everytime I fill it up and never had any issues with algae. I also use a 10, 5 and 2 micron filter bank. A tank of 1000 gallons lasts me about 2 to 3 years.

For the record, the Stabil Diesel treatment is NOT an biocide, so it did nothing to prevent algae in your storage tank. But it does help with condensation and claims to add lubrication too. Those filters are most likely the primary thing behind your success with stored diesel fuel. Ditto for fuel in a motorhome tank. High quality and low micron filters is the the best protection you can have.

 

[Derby6]

My 1999 7.3 Powerstroke has 250k and I never use any additives. No fuel system problems so far although I do change the fuel filter regularly.

That’s a good point. I too change filters regularly. Every other oil change for the most part.

 

[workinonit]

For the record, the Stabil Diesel treatment is NOT an biocide, so it did nothing to prevent algae in your storage tank. But it does help with condensation and claims to add lubrication too. Those filters are most likely the primary thing behind your success with stored diesel fuel. Ditto for fuel in a motorhome tank. High quality and low micron filters is the the best protection you can have.

Apparently I mistakenly pulled the wrong product link. What I have is a biocide as well as water treatment. I have a whole container in my shop but I'm not getting out in the cold to go look today. Thanks Gary for correcting me.

 

[CharlesinGA]

This video by the Motor Oil Geek is probably as good as it gets on Diesel fuel additives for lubricating pumps and injectors and keeping the system functioning. They did lab work on the 5 different ones he is discussing.

Charles

 

[bigbAZ]

For the record, the Stabil Diesel treatment is NOT an biocide, so it did nothing to prevent algae in your storage tank. But it does help with condensation and claims to add lubrication too. Those filters are most likely the primary thing behind your success with stored diesel fuel. Ditto for fuel in a motorhome tank. High quality and low micron filters is the the best protection you can have.

But wait, microbes need water to survive and multiply so you could say anything that reduces condensation in the tank helps to keep microbes at bay.

 

[Gary RV_Wizard]

Yeah, you could say that. And you can also say that neither a biocide nor a drying agent is helpful if you are in low-humidity environment.