Fuel additives. To add or not to add?

If high quality winter diesel is in short supply, the pour point depressants and anti-gel additives can indeed simplify operation of diesel vehicles in winter. However, things are never that simple. First of all, any additive, be it anti-gel or depressant, is a preventive measure and has no effect on the fuel post-factum, when the contents of the fuel tank has already separated, or worse, became a cream like substance. There are no simple ways to reanimate frozen engine, so no attempts should be made to kick-start the motor. It is far better to find a warm garage. Second, the efficiency of winter additive operation is depends a lot of the quality of the original fuel, and there is no guarantee that the same additive makes an equal positive impact on diesel from BP and diesel in a farm tractor. The third and last point to consider is that anti-gels and depressants modify only solved paraffins, therefore the actual effect requires that the additive be introduced into warm fuel. Summer fuel cloud point (the beginning of paraffin crystal precipitation) is -5°С. To give the depressant a chance, the temperature of the fuel when adding the depressant should be at least 10°С higher than that, otherwise it will have no result. But how can a vehicle owner warm up the fuel, beside putting the canister on a stove?

So, catch 22? Well, yes, in a sense. However, the risk to fill the tank with “frozen” fuel is significantly lower when filling up at large fuel stations. Such stations usually store the fuel in large underground tanks, which are naturally (ground) or artificially insulated. The diesel fuel in such tanks cools down relatively slowly, goes into the fuel supply line relatively warm and may well be suitable for additives. On the other hand, the probability of getting summer fuel instead of winter fuel is quite a bit lower at large fuel stations, which belong to companies which try to maintain the quality of the fuel supplied. At the same time, there is never too much of a good thing, and the winter additives will do no harm to winter fuel. The question is more of a cost effectiveness, which must be judged against the risk of getting summer fuel in winter.

 

By the way…

Compact electric heater in fuel inlets and fine filters are a serious competition to chemical additives.

Keep the following in mind:

– increased additive content past the max effective concentration has no effect on improvement of fuel cold weather performance;

– putting an additive into cloudy diesel is pointless, since the additive only influences dissolved paraffins;

– between fuel freezing point and filtration temperature, the latter is the more important parameter;

– a depressant can lower the minimum diesel temperature by no more than 10 degrees;

– quality of the diesel is a serious factor in additive efficiency;