Which Diesel Fuel Additive?

I have an 82 240D and I've been considering using fuel additives. I've heard that they give your engine more power and help keep your injectors cleen and do various other healthy things for old mercedes diesel engines. Is this true? What, if any, fuel additives do you guys use/recomend?

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Diesel Engine Specific Aid

Stanadyne is the best

It is interesting that you would put this post up on the very day that we have chosen to introduce our line of diesel fuel additives. We can not sing the praises of this product enough. There is a lot to be said about fuel additives and particularly diesel additives for the new ultra low sulfur fuel which unfortunately is not good for the health of your older Mercedes diesel. There is a lot of snake oil out there but why take the chance for a few cents a gallon. This stuff is NOT snake oil!

Of course everyone has an opinion, so I might as well weigh mine in here. That is if I don't bore you with all the text. :-). CLICK HERE to go right to the description of the product.

WHY DIESEL FUEL ADDITIVES? by Kent Bergsma

I get asked about diesel fuel additives on a regular basis. These requests have increased significantly since the introduction of Ultra Low Sulfur diesel into the US market in 2007. Our customers want to know how and when additives should be used, what will happen when they are not used, and which brands we recommend. We here at Mercedessource feel this is such an important issue that we are now offering diesel fuel additive information as well as product to all our diesel customers on our website.

There are a variety of diesel fuel additives on the market today. There seem to be so many now it is difficult for the average consumer to know what to buy! You can even purchase diesel additives at box discount stores! Just because it says formulated for Ultra Low Sulfur diesel doesn't make it a quality product. You could add a quart of Wesson (vegetable) Oil to your fuel tank and it would help with lubricity! As with any oil or fuel product - additives are not all created equal.

Most additives combine different properties to correct problems with the fuel or in fuel systems. Generally, these additives are used either to increase the performance of the engine, protect the fuel system from damage, minimize degradation or contamination of the fuel, or increase fuel flow in cold weather. Here is a list of those properties:

1. All "performance" additives attempt to make the fuel system work more efficiently by helping the fuel burn more completely. This in turn will produce more power from the same amount of fuel. Cetane is a number representing how readily diesel fuel ignites once it's injected into the engine. The higher the number, the more easily the heat from compression will cause proper combustion. Also, the higher the cetane number, the more easily the engine will start when cold and less white smoke is produced at cold start. A higher cetane rating can also help smooth our your diesel engine at idle (provided you have a mechanically healthy engine to start with).

2. Detergents are generally added and perform as you would expect. They can prevent residue build up by removing deposits from the fuel system before they have a chance to take hold. Fuel system deposits can be caused by lubricants in the fuel, bad fuel, or errant engine oil. These deposits can form on the interior of injection pumps or injectors, which would prevent the parts from moving freely. Excess residue deposits can result in hard starts, poor fuel economy, excess smoke, misfiring or rough running, and uneven idle or lopping. Carbon may also form on the injector nozzle tip (coking), which would affect the fuel spray pattern. This would result in incomplete burning of the fuel, low power, smoke and rough running.

3. Lubricity additives help to coat the critical fuel system components (injection pump and injectors). This provides a lubrication barrier between moving parts. In systems with particularly close tolerances, anything that reduces the lubricating properties of the fuel is a potential for damage. Water that is absorbed into the fuel, alcohol from some fuel additives, gasoline mistakenly added to the tank or used to kill algae, or use the newly formulated diesel fuels can all cause the lubricity of the fuel to decrease leading to premature wear. Lubricity additives can help to reduce or prevent damage to the fuel system in cases of contamination. When fuel system maintenance is to be performed, a lubricity conditioner should be added that would be beneficial in preventing damage which could result from dry cranking or during the first start. WARNING: A lubricity additive is a must for older diesel engines that were not designed for the Ultra Low Sulfur diesel fuel. In the past sulfur was the key lubrication element added to the fuel. Without it, your injection pump and injectors WILL suffer. A quality fuel additive can restore the lubricity that has been lost since removal of the sulfur from the fuel. This alone is enough reason to use additives on a regular basis.

4. Catalysts are added to diesel fuel to suppress black smoke emissions. Most catalyst compounds cause the fuel being injected into the cylinders to burn more completely, which reduces the amount of particulate emissions (soot) being exhausted from the engine.

5. Water can cause a number of problems in the fuel. Diesel fuel has an inherent problem of being hydroscopic, which means it readily absorbs moisture from the air. Other than the obvious problem of being non-combustible and the potential for freezing and restricting fuel delivery, water also causes corrosion of fuel system components and reduces the lubricity of the fuel, both of which result in wear. Many fuel additives contain chemicals that disperse moisture in the fuel. If the moisture is dispersed, it cannot concentrate in one area and cause a restriction in fuel delivery if it freezes. In addition, being dispersed in the fuel allows the moisture to be carried to the water separator where it can be removed from the fuel.

6. Cold weather protection can be added to the fuel. In cold conditions two problems may occur. First, any water present in the fuel system can freeze and interrupt fuel delivery. De-icing or freeze depressants lower the freezing point of the water to prevent this from happening. The second problem is know as gelling, which is what happens when wax crystals form in the fuel. This effects how well the fuel flows and can reduce fuel delivery to the point of preventing the engine from starting. Pour-point depressants lower the temperature at which the fuel will flow and wax dispersants keep any crystals evenly distributed throughout the fuel. To be effective, pour-point depressants and wax dispersants must be added before gelling occurs.

7. Another problem related to moisture in the fuel is organic contamination. Moisture in the air contains micro-organisms. When moisture is absorbed by diesel fuel, and the water is allowed to collect or concentrate, these microorganisms can multiply to the point where problems may occur. Usually this problem only occurs where fuel is allowed to sit around for prolonged periods. But once in truck, algae can plug fuel filters and passages in the injectors or injection pump. In some cases fungus or slime will form inside areas of the fuel system and produce an organic acid which will corrode fuel system components. A biocide should be used in tanks to prevent the fuel from becoming contaminated, and can be used if contamination has spread inside your vehicle tank.

8. Corrosion inhibitors are also often added and can protect the fuel system components from rust formation by coating the metal parts. Fuel stabilizers maintain the integrity of the fuel to prevent the formation of deposits in the fuel system. Anti-oxidants reduce the reaction of oxygen with the fuel to help stabilize the fuel and prevent rust.

RECOMMENDATIONS: Now more than ever!

I recommend the use of fuel additives on a regular basis that raise cetane rating and increase lubricity, and have detergent, anti-corrosion and water dispersants. It use to be that you could add them one every two or three fill ups, but now with the ultra low sulfur diesel you should be using an additive at each fill up. Use them religiously during wet weather or in winter when problems are more likely to occur. Cold weather really needs cetane and lubricity increasers, water and wax dispersants, and freeze and pour-point depressants.

Which additive? First and foremost, I believe it should be a fuel additive made by a fuel injection or fuel systems manufacturer. That way you know they have more than just a surface knowledge of the inner workings of a diesel fuel delivery system. Be careful of additives made by lubricant only manufacturers especially if they contain alcohol. Also, keep in mind some brands of cetane boosters can cause injector "nailing" to become more pronounced as cetane boost alone can affect the thermal stability of the fuel. For this reason, an additive that combines several of the properties listed above would be more beneficial than one that provides only one property.

Since the Stanadyne Corporation is the leading U.S. manufacturer of fuel injection pumps, injectors, fuel filters, water separators of diesel fuel additives, you need to look no further. We are proud to now offer our customers the Stanadyne Performance Formula additive in single 16 oz or economical 3 pak sizes. Each 16 oz. bottle will treat up to 60 gallons of fuel. CLICK HERE to go directly to the product description.