Winter is here! Diesel Fuel Anti-Gel Explained

[Duluth Diesel]

Register to stop seeing this ad!

All diesel fuel inherently has water in it. That is why your truck has a fuel/water separator built into the fuel filter assembly that you periodically have to drain.

Two things happen to diesel fuel in the cold. 1) The paraffin (petroleum wax) component of the diesel fuel will polymer together, forming a wax layer in your fuel. This is called gelling. Once the paraffin wax forms, it is very hard to reintegrate back into the fuel. This wax will clog your lift pump and fuel filter, leaving you dead on the side of the road. 2) The water component in the fuel, which is impossible to avoid with diesel fuel in most cases, will turn into ice. Since fuel and water do not mix, the water component will separate out in your tank. As this turns into ice, the ice crystals stack up on the the filter face, causing filter icing. This will also prevent fuel flow and starve your engine of fuel.

So, any wise diesel owner should do three things in the winter:

1) Always carry a spare fuel filter in your truck for roadside emergency use.

2) Run an anti-gel diesel fuel additive that prevent paraffin wax polymerization, but also has a deicer that prevents ice crystal buildup. LINK: AMSOIL Diesel Concentrate with Cold Flow Improver

3) Keep 1 bottle of fuel reintegration emergency additive in the truck. This is smart to have in case you do have a gel or ice issue, it can reintegrate the fuel. LINK: AMSOIL Diesel Recovery Emergency Fuel Treatment

Ensuring that you run an anti-gel in the winter will keep you on the road by preventing gelling and icing.

Anti-gel explained:

Wax forms plate like structures (flat) and AMSOIL Cold Flow breaks those up, more like strings, so fuel can flow through. It modifies the wax crystals to allow the fuel to pass through filters, and prevent premature plugging due to gel. It also works well with biodiesel blends as well. Biodiesel has horrible cold temperature properties in general, and the use of a biodiesel-compatible product will help lower the point at which the fuel clouds, or begins to gel. Biodiesel or B100 does not contain paraffin since it is not petroleum based. When B100 gets cold crystals do appear and they act like wax in that they stick together and are large enough to plug filters. These crystals form sooner or at higher temperatures and are larger in size in B100 than in regular diesel fuel. Biodiesel is defined as mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats which conform to ASTM D6751 specifications for use in diesel engines. The saturated compounds in the Biodiesel form the crystals that plug filters. When they form they are larger than diesel wax crystals. Most anti-gels, including AMSOIL's, work best on biodiesel fuels B20 and less.

The key to messing with paraffin wax gel is to disrupt it from agglomerating together into a “glob” that is big enough to plug a filter and or fuel line. A copolymer chemical with molecular chains similar in size and distribution to paraffin co-crystalize with the wax and disrupt the crystal formation, thereby allowing your fuel to continue to flow through your fuel filter and keep you on the road.

As diesel fuel cools you will notice a white haze or cloud in the fuel. This usually happens around +10 degrees F. but can happen at higher or lower temperatures depending on fuel characteristics. The white cloud or haze is caused by wax crystals precipitating (coming out of solution) out of the fuel and becomes visible. When fuel warms above the Cloud Point of the fuel, the white appearance will disappear as wax crystals dissolve back into the fuel. The use of an anti-gel usually does not change the Cloud Point of a fuel, and if it does it is usually only by a few degrees. There are however some Cloud Point depressants that can significantly reduce the Cloud Point of a fuel. Cloud Point depressants will adversely affect anti-gels or Pour Point Depressants, however. Anti-gels typically affect the CFPP (cold filter plugging point) and Pour Points of a fuel. Anti-gels work on the wax crystals in the fuel. As the wax crystals form or come out of solution, the anti-gel will modify the wax crystals so they are smaller, will not stick together and will continue to flow through the filter in much lower temperatures than untreated fuel.





ULTRA-LOW-SULFUR DIESEL FUEL CHALLENGES
The reduced sulfur levels in modern ultra-low-sulfur diesel fuel (ULSD) result in reduced lubricity, the property that controls wear in the fuel injectors and fuel pump. Improving lubricity in ULSD is difficult because it must be done without adding sulfur back into the fuel. Additionally, ULSD is subjected to extensive refining, making it even more difficult to treat. For these reasons, many competitive claims are not based on ULSD fuels, rendering them inaccurate and irrelevant. AMSOIL Diesel Concentrate Plus Cold Flow Improver is formulated specifically for modern ULSD fuel. It improves lubricity, helps maintain engine oil TBN and prevents soot loading.

SUPERIOR COLD-WEATHER PERFORMANCE
As the temperature drops, the wax naturally found in diesel fuel begins to form crystals. The point at which wax crystals form is known as the cloud point. These wax crystals eventually clog the fuel filter and starve the engine of fuel, preventing it from starting. While low quality fuels may form wax crystals in temperatures as warm as 40°F (4°C), most fuels have a cloud point near 32°F (0°C). The point at which the wax crystals clog the fuel filter is known as the cold filter-plugging point (CFPP). AMSOIL Diesel Concentrate Plus Cold Flow Improver lowers the CFPP by as much as 34°F (19°C) in ULSD.

It also reduces the pour-point temperature of treated diesel fuel, providing better fuel delivery to the injectors during cold weather. It is formulated with a jet-fuel-type deicer that disperses water to control ice formation in all sections of the fuel system. Diesel Concentrate Plus Cold Flow Improver minimizes the need for the use of #1 diesel fuel, enabling better fuel economy, performance and lubricity.

POUR POINT VS. CFPP
It is important to distinguish between CFPP and pour point. Many competitors make great claims regarding pour point, leading consumers to believe their products are superior when they actually have an inferior CFPP. Once fuel surpasses its cloud point, the wax crystals begin to clog the fuel filter. The CFPP temperature is a more important characteristic than pour point because the engine will not run if fuel cannot pass through the fuel filter.

[blue7.3]

Duluth, great technical article! This is what we need here. Especially since many here do not appear to currently own diesels. I very much appreciated the comparison between AMSOIL and Power Service (is what I buy from NAPA). I did not know PS cost more though. I'll have to run some numbers...

Regarding ULSD lubricity, I've read so many different theories on that. But I run PS octane boost w/ their version of lubricant in the summer just in case. I imagine AMSOIL has a version of that product also? How does it compare?
cheers,
-pete

[Duluth Diesel]

Originally Posted by blue7.3

Regarding ULSD lubricity, I've read so many different theories on that. But I run PS octane boost w/ their version of lubricant in the summer just in case.

You mean cetane boost, right? Octane would be for gasoline engines, not diesels.

I imagine AMSOIL has a version of that product also? How does it compare?
cheers,
-pete

AMSOIL's summer diesel additive is AMSOIL Diesel Concentrate.

Cetane lowers the flash point of diesel fuel. It doesn't really add any energy or Btu content to the fuel. In the winter, cetane is advantageous since it makes diesel fuel easier to ignite at lower temperatures. This also improves combustion, which is good for minimizing incomplete ignition/combustion that results in cylinder wash down. Cylinder wash down in a diesel means that the unburned (incompletely combusted) diesel fuel washes down the cylinder walls, causing piston ring lubricity to suffer, which can lead to cylinder wall scoring and ring deterioration. It also leads to oil dilution (fuel contaminating oil) which deteriorates the oil's TBN (total base number) and lubricating properties.

Getting back to Cetane, since it lowers flashpoint, is an additive that is overused and misunderstood. In warmer months, especially when towing where cylinder temps and exhaust gas temperatures can be between 1,100 and 1,400 degrees Fahrenheit sustained, cetane can do a disservice. Lowering the flashpoint of diesel fuel in these high temperature situations can cause preignition (fuel combustion before the piston reaches top dead center, or TDC). This can cause a drop in power, a drop in mileage, and excess piston face stress. In an extreme case, usually in modified engines, this can promote piston failure, which inevitably leads to engine failure. I know Cetane is advertised as a power enhancer, and people tend to over treat with it quite a bit in my experience. For this reason, AMSOIL's Diesel Concentrate does not include a Cetane Booster additive. AMSOIL offers a separate product, AMSOIL Cetane Boost, as a stand alone cetane additive. This leaves the end user the option of adding or not adding cetane to their fuel depending on ambient temperature, engine demands and operating temperature, and fuel quality.

Running Power Service with Cetane Boost will not cause your engine to fail. My example above is an extreme case, in a modified diesel engine with gross over treatment. But, if you're paying money for a cetane boost that is causing you to see a drop in rear wheel horsepower and a drop in mileage, wouldn't you like the option to omit cetane additives during the warmer months?

-Chuck

[blue7.3]

Chuck, you're making a believer of me. Tech-knowledge w/ actual data is invaluable. I run the PS cetane (thank you for correcting me... ) boost w/ "Slick 50" additive mostly because of the ULSD lubricity worries. I've never seen an increase in mileage. Probably means I'm tossing $.
-pete

[Duluth Diesel]

Well when you want to try something better let me know, Pete. If you ever want to talk diesels, PM me and I'll shoot you my cell number.

-Chuck

[DFW MAHINDRA]

I run amzoil in my Dodge Cummins, (three of them) my diesel mower and my old Harley Shovelhead. I am sold on Amzoil, read the tests there is no comparison. We run our company trucks 15,000 miles (we change the filters at 7500). I have saved money using amsoil.
Bob

[graydonblair]

A friend of mine did some tests with the Amsoil Cold Flow Improver product last winter. We make Biodiesel and winter can be nightmare on gel points with Biodiesel.

Of all the products I've seen, read about, played with, or heard of, the Amsoil stuff just blew them away!

We were able to run B100 (100% Biodiesel) in the tank this winter in a 2003 Ford 7.3 and never had a single gel up in the tanks using the Amsoil product. Before my friend dared try that, he took some Biodiesel and blended the Amsoil cold flow product into it in different ratio's. He then stuck the bottles in the freezer to see what would happen.

The results were amazing! In the smallest concentration, the Bio did sort of gel up but it never got solid. It's the best stuff I've ever seen for cold flow & Biodiesel!

We had a week in Utah where temps dipped in the 0 to 10 deg. F range. The truck with 100% Bio and the Amsoil cold flow improver in it was sitting in a parking lot for 8 hours a day in the blistering cold & wind up on a hill (Hill Air Force Base) in the winter chill.

There were a few days that my friend thought for sure he'd be calling a tow truck, but every time it fired right up & ran great! Made a believer out of me!

I don't know how well it works on all types of Biodiesel (Bio can be made from various types of oils; ours was made from Canola feedstock, which does pretty well in winter weather already, but would've been a solid lump in that cold onslaught we had). But I can say for the stuff we had it worked INCREDIBLY well!!!

You've got my vote Amsoil!

[Duluth Diesel]

Wow thanks for posting up your experience!

-Chuck

[blue7.3]

Hi Duluth!
Well I've run out of my PS stock, so will visit your store and get your winter formula. I have a question regarding your summer product (just lubricity, my truck is stock and I've since read other accounts regarding cetane -boost discussions. Makes all the sense in the world that I don't need it). How does your summer product compare to two-stroke TCW-3 oil for lubricity, and are there any other advantages to your product over it?

thanks,
-pete

[Duluth Diesel]

AMSOIL Diesel Concentrate and AMSOIL Diesel Concentrate with Cold Flow are some of the better additives on the market when it comes to lubricity.

Running 2 stroke is the best thing for the HFRR (lubricity) rating in fuel, but 2 stroke oil doesn't give you fuel detergency, stability, anti-gel qualities, etc. In my 2002 Dodge Cummins, I run AMSOIL Diesel Concentrate (and Diesel Concentrate with Cold Flow in the winter) and I add in AMSOIL Interceptor 2 stroke oil for added lubricity. I do this because 1998.5 - 2002 Dodge Cummins trucks have the Bosch VP44 injector pump that is especially sensitive to fuel HFFR ratings for injector pump survival.

The lower the HFRR number, the better your lubricity. This chart was taken from mopar1973man.com (Michael Nelson). Michael is a guy who is a big proponent of 2 stroke oil in diesel fuel as a lubricity improver. I've had many good conversations with Mr. Nelson and agree with him on most points. I contend that while 2 stroke oil DOES add lubricity, it doesn't do much for gel point, and it does nothing for detergency. Keeping your fuel system and injector nozzles clean is important to mileage, power, and to keep from scorching pistons. That's why I run AMSOIL Diesel Concentrate as well as AMSOIL Interceptor 2 stroke oil. I get fuel stability, anti-gel, detergency, and ultimate lubricity. I've been running this combination of additives for years now with perfect results.

Running 2 stroke in diesel fuel is against all manufacturer recommendations. No manufacturer will tell you to run 2 stroke oil in diesel fuel, since that use is inconsistent with the labeling and intended purpose of 2 stroke oil. But the facts on HFRR speak for themselves. Also, I don't recommend running 2 stroke oil in any diesel engine that is designed to run ULSD fuel. Lubricity is mostly a concern for diesels that were designed to run on LSD and HSD fuels and that can be damaged by the commonly poor lubricity ratings of ULSD fuels.