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Fuels & Lubricants Discussion all about Fuels & Lubricants. synthetic oil, conventional oil, brands, change intervals, diesel grades, gelling and such debated items like that. Non TDI related postings will be moved or removed. This forum is NOT for the discussion of biodiesel and other alternative fuels.

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Old March 5th, 2001, 08:22   #1
Join Date: Mar 2001
Location: Royal Oak, Michigan, USA
Default Symptoms of Gelled fuel?

I think that it finally happened to me...

This morning (21 degrees F) my 2000 NB would not continue running. It will crank and begine running poorly, but will never achieve a normal idle. The firing is uneven and plently of smoke is present. I fueled up last Tuesday and although the weather has been cool, (18 degrees Saturday night), I have not had the problem before. Even when I moved the car on Sunday (afternoon - 45D), it did not show any signs of poor running.

I dumped a full bottle of anti-gel into the tank and got a ride to work. I'll try again this afternoon.

I'm thinking that maybe I got a tank full of non-winterized fuel, as it's been a little warmer around here for a few weeks. What else could it be? I've had good luck with the Mobil station that I always use...

If anyone has experienced the gelling fuel problem, what were the symptoms and did the temperature change return the car to driveable status?

In soon to be snowy Michigan.
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Old March 6th, 2001, 05:48   #2
Join Date: Dec 2000
Location: Woodbridge VA
Default Re: Symptoms of Gelled fuel?

diesel = smoke. gelled diesel = no fuel = no smoke? wouldnt this be the case? wouldnt the presence of smoke mean the engine is getting fuel just fine? I have never seen a case of gelled diesel in my life, so I just do not know. did you try applying some throttle? you say it never achieved a normal idle, how long did it run? possibly a burnt out glowplug or loose connection causing 1 / more to malfunction.
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Old March 6th, 2001, 06:38   #3
Turbo Steve
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Join Date: Jan 2000
Location: .
Default Re: Symptoms of Gelled fuel?

How Diesel Fuel Gells

"Diesel Anti-Gel Compounds - Diesel fuel is comprised of hydrocarbon molecules with about 12-22 carbon atoms and many of the higher molecular weight components such as cetane (C16H24) would be solid at room temperature like butter or fat. When diesel fuel is cooled, many of these higher molecular weight components will start to solidify and form a waxy precipitate. A 2% wax out of the solution is enough to gel the remaining 98% of the fuel remaining. This will block the fuel filter in the fuel injection system as well as the
fuel lines.

"Wax crystals form as thin plates which overlap and interlock. Anti-waxing or antigelling compounds do no prevent the wax formation, instead they work by modifying the wax crystals to a dendritic needle-like form and this reduces their tendency to interlock. The crystals still collect on the outside of the filter, but they do not block the passage of liquid fuel. The anti-waxing additives in commercial use are copolymers of ethylene acetate and vinyl acetate, or other similar alkene-ester copolymers. The performance of these additives varies with the source of each batch of refined middle distillate diesel fuel and their cold weather resistance improvement effects decrease as the doseage rate is increased.

"If correct fuels are refined as stipulated in accordance with European standard EN 590 or DIN 51601 in Germany, such additives are no longer necessary and filterability is guaranteed down to at least -15 degrees C.

"Commercial winter grade Diesel #1 fuel guarantee a cold resistance down to at least -22 degrees C. with the addition of these additives, although poorly refined or contaminated fuels will perform more poorly when subject to cold weather.

"Diesel Anti-Ice Compounds

"Anti-ices have a high affinity for water (alcohols and glycols) and are soluable in diesel fuel. Water is present as a contaminant in diesel fuel usually as an emulsion (about 200ppm) resulting from condensation in fuel tanks as a consequence of humid air.

"Visible water in diesel fuel is gross contamination above the 200 ppm emulsion levels and results from improper storage in the transportation of the fuel. The alcohol or glycol compounds assist in the further solubilization of the emulsified water in the diesel fuel to keep it in suspension with the resultant avoidance of ice crystal formation. Water levels above the 200ppm concentration emulsion level, as evidenced by visible water standing in bottom of diesel fuel tanks, are not solubilized by the anti-icing compounds and remain subject to ice formation which is the most common reason for blocked fuel pipes or fuel filters."

Reference: Owen K. and Coley T. (1998) Automotive Fuels Reference Book, 3rd edition, SAE, Warrendale, Pennsylvania.
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Old March 6th, 2001, 06:43   #4
Turbo Steve
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Join Date: Jan 2000
Location: .
Default Re: Symptoms of Gelled fuel?

Here's a few highlights from VW's recent TSD on using anti-gell additives when operating all of their diesels in temps at or below 32*F. / 0*C.:


Subject: Diesel Fuel, Cold Weather Conditioning for Driving at Temperatures Below 0*C. (32*F.)

Models: All with Diesel Engine
Group: 20
Number: 00-03
Date: Dec. 8, 2000


Poor diesel engine performance in ambient air temperatures below freezing 0*C. (32*F.) can be caused by a condition known as diesel fuel clouding (gelling / waxing), a result of improperly winterized / conditioned diesel fuel provided by fuel suppliers. Water contamination in diesel fuel can also cause similar conditions as the result of ice accumulation in the vehicle's fuel system.


To prevent the possibility of this condition occurring, [we] recommend to diesel powered vehicle owners that a quality fuel winterizer / conditioner be used during winter months. VW recommends using Standadyne Formula Fuel Conditioner in the correct amount per One Shot Performance tank full of fuel as All Season Diesel listed below.*

*Add 8 oz. (235ml) per 15 gallons (60ltr) of diesel fuel of Standadyne Formula Fuel Conditioner directly to the fuel tank.

VW Part #ZVW 340 002.

Note - For vehicles which will be operated at temperatures below -30*C. (-22*F) add 12-oz. (355ml) per 15 gallons (60 ltrs) of diesel fuel.


Click here for additional info about the rest of VW's TSB, as it explains how to inspect the diesel fuel system for contaminants such as water, ice, moisture, clouding, gelling, or waxing.

FYI - The best way to avoid having your fuel filters ice-up with wax crystals is to take steps to prevent the problem from happening in the first place! Afterall, an ounce of preventitive maintenance is much better than a pound of redemptive cure.

Water, sludge, microbial organisms, and other contaminents are previlent this time of year and a diesel additive is needed more than ever before with the low-quality fuel we have to choose between. Because of these extra wintertime challenges, VW finally is recommending the use of a all-season diesel additive when temps drop to 32*F.

Furthermore, an example of a preventitive maintenance step to prevent fuel from gelling might be using a triple dose of Power Service's Diesel Fuel Supplement or their Arctic Express Antigell (at double the dose in cold temps) or your personal favorite winter additive.

Obviously, this can mean the difference between stranged or arriving safely to your destination. I don't recommend anyone take their chances, hoping that the "winterized fuel is blended properly." At least, not with your life and possibly that of your family on the line.

Furthermore, because you can never tell how high the quality of fuel your taking on is, I strongly suggest that you carry a 96-oz. bottle or at least a quart size container of Power Services 911 in your trunk in case of an emergency i.e., a plugged up or frozen fuel filter which needs to be melted down or unthawded.

Diesel 911

For year-around use. Diesel 911 can rescue diesel-engine operators from the most common fuel emergencies they encounter.

* It De-ices frozen fuel-filters.
* Reliquefies gelled fuel in minutes.
* Completes microbial clean-ups - when used with Power Service Bio Kleen Biocide or any other biocide.
* Disperses sludge and reduces fuel-filter plugging.
* Removes water from diesel fuel -- protects fuel-injection pumps and injectors


Ric's Fuel Power Chemical Company makes a similar product to Power Service's 911 which was designed to melt through the icey wax crystals.

* It Dissolves Gelled Fuel
* Emergency Road Treatment specifically formulated to dissolve gelled fuel back into solution and return the flow in approximately 20 minutes.
* Will Not harm fuel pump injectors
* Will Not harm precombustion components
* Gets fuel flowing in 15 - 20 minutes
* Compatible with all types of fuel

Meltdown and 911 are to be used only in an emergency road treatment only. They can be purchased at most Walmarts or your local truck stop. 96-oz. containers run about $10.00 while the smaller 32-oz. bottles run in the $4.00 - $5.00 range.

A few ounces of preventitive maintenance with additives is much better than a pound of redemptive cure with a tow truck.
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Old March 6th, 2001, 06:46   #5
Turbo Steve
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Join Date: Jan 2000
Location: .
Default Re: Symptoms of Gelled fuel?

FYI - Here's a little Q & A session from Power Service that outlines frequently asked questions about additives and why diesel engines need them to operate at peak efficiency:


There are many problems that can arise with diesel engines. Many of these problems can be solved with diesel fuel additives. The most common problems experienced by diesel-engine operators are:

A. Loss of Power / Increased Smoke / Increased Fuel Consumption:

In most cases, all three of these problems relate back to a dirty injection system. To solve these problems, you have two choices: a.) have the injection system removed and calibrated at an extremely high cost, or b.) solve the problem chemically with diesel fuel additives to clean the injection system and return the engine to peak performance. Power Service diesel fuel additives solve these problems at a fraction of the cost.

The best way to prevent these problems is to maintain a clean injection system. This requires cleaning the system on a regular basis, with an additive like Diesel Kleen Performance Improver. Power Service recommends treating your fuel each time you change engine oil. Cleaning fuel injectors and maintaining clean injectors with Power Service Diesel Kleen will result in increased power, reduced exhaust smoke, and significant improvements in fuel mileage.

B. Water in Fuel:

Water in fuel is the number one fuel complaint voiced by diesel-engine operators. Ongoing tests of diesel fuel samples collected from refineries and pipeline terminals across the nation reveal that all diesel fuel contains an average of 50 parts-per-million of water. The water inherent in all diesel fuel is compounded by condensation created by the higher operating temperatures of the new electronic engines. Fuel circulating around the fuel injectors returns to the equipment tanks at higher temperatures than in older model engines, resulting in condensation that settles inside the tanks. Year around, the water in untreated diesel fuel can reduce fuel-filter life and cause premature wear on fuel-injection pumps and injectors. In sub-freezing temperatures, the water in untreated diesel fuel freezes on the face of fuel filters. Fuel flow to the injection system is restricted and wax precipitates as the flow of warm fuel returning to the tanks is reduced. Engine shutdown and fuel gelling result as fuel filters plug up with ice and water. Power Service Diesel 9🯍 is the most effective additive for dispersing water in diesel fuel. The water in diesel fuel is dispersed so completely that it burns harmlessly during combustion.

C. Fuel Gelling:

Unlike gasoline, diesel fuel transforms into a semi-solid state at low temperatures ( +10癋). This results in fuel starvation and engine shutdown as fuel flow to the injection system is restricted and the build-up of wax on fuel filters reduces the flow of warm fuel to the tanks. Engine manufacturers are equipping the new electronic engines with 10-micron fuel filters for optimum fuel protection. However, the 10-micron fuel filter severely restricts fuel flow to the injector when operating in extreme cold. Arctic Express Antigel and Diesel Fuel Supplement prevent fuel gelling in temperatures as low as -40 F. and keep fuel liquid during extended engine shutdowns in severe cold. Power Service Arctic Express Antigel and Diesel Fuel Supplement are the additives for all diesel-engine operators who pre-plan to prevent fuel gelling.

D. Microbial / Fungi Growth:

Of the nearly 12 billion gallons of diesel fuel consumed annually in the United States, less than one percent is treated with an antimicrobial agent. This microbial or fungi growth can manifest itself as a black, stringy substance that traps on fuel filters and fuel-injector screens. However, contamination often goes unnoticed until symptoms become severe because a transparent film can also plug fuel filters. As metabolic waste and cells accumulate, they settle out as sludge which accumulates on tank bottoms. This problem can even cause pin holes and corrosion within the fuel system due to the production of organic acids. Power Service Bio Kleen Biocide provides "shock-treatment" kill of microbial growth plus effective, economical prevention of future microbial growth. Power Service Diesel 9🯍 disperses water and microbial sludge making any biocide kill quicker and more effective. Continue with regularly scheduled maintenance treatments to control microbial growth.


These types of symptoms are indicative of a dirty fuel-injection system. To solve these problems, use Diesel Kleen Performance Improver as directed on the container to clean the injection system. Power Service Diesel Kleen meets Cummins L-10 Superior Specifications for Cleaning Fuel Injectors and upgrades No. 2 diesel fuel to premium quality.


Year around, the water in untreated diesel fuel can reduce fuel filter life and cause premature wear on fuel-injection pumps and fuel injectors. Power Service Diesel 9🯍 disperses the water in diesel fuel so completely that it burns harmlessly during combustion. The first thing you should do is to drain/pump off as much of the water that you possibly can. Add Power Service Diesel 9🯍 to your tank at a treatment ratio of 32 ounces to every 25 gallons of fuel.


When fuel treatment is delayed until fuel filters have plugged and/or fuel has gelled in the equipment tanks, Power Service Diesel 9🯍 will solve this emergency. Remove the fuel filter and fill it with Diesel 9🯍. Reinstall the fuel filter, and start the engine! You are now operating on winterized fuel. Power Service saves the need for a service call or tow truck, so it pays to keep a container on hand just for winter emergencies. Maintain fuel operability by adding Arctic Express Antigel or Diesel Fuel Supplement at the ratio recommended on the containers at each subsequent refueling.


Planning ahead to deal with winter fuel problems is the best way to keep them from happening at all. Arctic Express Antigel and Diesel Fuel Supplement are preventive measures that prevent fuel from gelling in temperatures as low as -40 F. Arctic Express Antigel and Diesel Fuel Supplement keep fuel liquid in equipment tanks, even during extended shutdowns in severe cold.


Lubricity has been a growing concern in the diesel fuel market place since the introduction of low sulfur fuels in 1993. While low sulfur fuels are mandated by the EPA due to their environmental characteristics, low sulfur fuels have a marked decrease in lubricity. Costly maintenance and repairs from increased wear rates on pumps and injectors result from an engine not receiving adequate lubricity. All Power Service diesel fuel additives meet or exceed engine manufacturer's requirements for lubricity.


See also - Cetane 101 or What Fuel Was Intended For Our TDI

Anti-gell 101

VW recommends Anti-gell additive when temps are at 32*F. or lower:
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Old March 6th, 2001, 08:21   #6
Join Date: Mar 2001
Location: Royal Oak, Michigan, USA
Default Re: Symptoms of Gelled fuel?

Gee, thanks Steve. I just wish that you would be more comprehensive...

I tried it again when I got home. My conclusion is that it is not gelled fuel. The car will start, but never achieve a steady idle. The throttle has no effect on the engine speed, and feels like it is not attached (which of course it isn't, being drive by wire). I tried until it would not even start (3 times) and quit. I called VW (actually AAA in Florida) and they sent a wrecker for the tow. I'll check soon at the dealer and give an update here, or in a more appropriate thread.

I printed the information and will consult it to learn more about gelling. It's been much colder and I've not had a problem (no additives as I cannot find power service around here), so maybe the Mobil fuel is OK after all.

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Old March 6th, 2001, 09:55   #7
Join Date: Mar 2001
Location: Royal Oak, Michigan, USA
Default Re: Symptoms of Gelled fuel?

The conclusion is fuel contamination, and a bad case at that. The dealer is talking about a full system drain and new filter, etc. They said that they have been having a number of incidents like this within the past few weeks and even have a map showing the stations were bad fuel was encountered. I'm pissed off at Mobil, and know that if I raise hell at the station, I'll get exactly bubkis and a lot of frustration. I love the car and treat it well, but the Russian Roulette of fuel is starting to really piss me off.

Thanks for the help everybody.

In case anyone needs the whole story:
The car would start but only run a second or two, with plenty of black smoke. It drove absolutely fine from Tuesday (when I filled it up) until I tried to start it yesterday. Would not run at all after a few tries. The dealer found water and "grey fuel" in the tank (which is some other contamination - sludge or some other fuel product) and is cleaning the system, etc. I wonder where they are going to get "the proper fuel"...

Ron (now walking)
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Old March 6th, 2001, 11:05   #8
Join Date: Dec 2000
Location: Woodbridge VA
Default Re: Symptoms of Gelled fuel?

wow. I'm suprised at the fuel problems I hear about on this forum. In all my life, I have never run into bad diesel. I have a 83 Volvo with a VW I-6 turbodiesel, (hog, 28MPG) Buy fuel in no particular place, notice no differences in performance, use BG 248 Max Diesel Performance additive every 10th or 20th tank (we sell it at work). Passing 280,000 trouble-free miles, It has required little more than timing belts (this beast has two, front and rear) and filter changes. I used RotellaT until I found this forum and found Delvac1, changed at 15-20,000 mile intervals. (I dont test my oil). Obviously the recipe for success revolves around the fact that VW builds bulletproof machines.
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