Diesel and Water

**gregg_g** · September 19th, 2005 11:13 AM

Hello everyone,

I know that coming up with this thread is a little bit lame, but I could not just help it to question, that why is it that water is likely to be present in diesel than gasoline?
In gasoline engines you don't see a water separator device, and in diesel engines there is...
Hope any of you tsikoteers can help me answer this query... thanks

gregg_g

**yebo** · September 19th, 2005 11:34 AM

that's due to what happens to gasoline and diesel during storage, including it's stay in the fuel tank. gasoline, having a lower flash point evaporates more readily than diesel. the gasoline vapor prevents the entry of air (and thus water vapor) inside the storage tank/fuel tank. the reverse is true with diesel, it hardly evaporates (except when you're in the desert where temperatures are very high). so since their is no diesel vapor the storage tank/fuel tank sucks in air (and consequently water vapor) during the night when the temperature is low. the water vapor condenses on the diesel surface and settles at the bottom. during the day the temp rises a little bit and air is expelled out of the tank, and the cycle repeats itself again during the night, condensing more water into the fuel tank.

**altec** · September 23rd, 2005 08:35 PM

if thats the case, it is not good for diesel rides to wait till the fuel is almost used up before refueling? Better to refuel full tank and when it is like half tank, instead of near empty?

**diesoline** · September 23rd, 2005 10:35 PM

yes, it is. it is better to refuel as soon as possible in order to avoid condensation inside the fuel tank. problem is, current diesel prices make filling up more often more unpleasant than before.

expect more smoke belching and power loss problems to crop up in the future as water-related problems like damaged injectors and nozzle tips, especially on public utility vehicles, affect the injection system's ability to combust fuel efficiently.

**yebo** · September 23rd, 2005 10:42 PM

yes correct. the smaller the air volume on top of the diesel then the smaller will be the cold air (and consequently water vapor) that will enter during the night.

nevertheless it is always a good practice to drain the condensate from the diesel fuel tank once a year. it will not only save your injection pump and nozzles, it also prevents rust build up in the fuel tank. this does not take much effort. just use up as much of the diesel in tha tank and when the fuel gage is almost at empty, then open the drain plug at the bottom and drain everything (do i need to say that make sure you have a gerycan of clean diesel to fill into your tank afterwards hehehehe?) do not throw away this diesel that you drained, put it in a clear plastic bottle (an empty 2 gallon mineral water bottle will do since the tank probably has less than 8 liters left with the fuel gage at almost "E") and let it stand overnight for the diesel to separate from the water. then you can decant the diesel from the water and put it back again into the fuel tank.

**gregg_g** · September 23rd, 2005 11:06 PM

Thanks Yeb... Btw, how come your so good at this? Is your work related to this or are you just a diehard enthusiast with Diesel vehicles?

**yebo** · September 23rd, 2005 11:34 PM

me good? you believe me? actually i write fiction for a comics magazine nyahahahahaha! joke :D

chief siraniko po ako on an offshore oil drilling rig kaya may alam ako sa mga bagay na yan. i know just enough not to do serious damage ehehehehe! i have 10,500KW of diesel power running in the engine room right now :wink:

**GlennSter** · September 23rd, 2005 11:40 PM

Originally Posted by yebo

me good? you believe me? actually i write fiction for a comics magazine nyahahahahaha! joke :D

chief siraniko po ako on an offshore oil drilling rig kaya may alam ako sa mga bagay na yan. i know just enough not to do serious damage ehehehehe! i have 10,500KW of diesel power running in the engine room right now :wink:

bwahrharhar

that's my ninong