Algae in fuel tank

I recently was losing power on uphill grades and took the motor home to an authorized CAT engine shop. They discovered that there was algae in the diesel fuel tank, which had clogged the fuel filter. As explained to me by the service manager, this is a common problem with any rig, RV or 18 wheeler, that sits for several months ? more so in the colder months.

My rig is three years old and has never had this issue. Normally, it is used regularly, but this past winter, it sat for about four months. I suspect that I picked with the algae from a refueling prior to parking it for that time period and it multiplied.

The typically correction is to remove the tank and steam clean it, but this particular shop did not have lifting equipment for a large RV. I purchased some Biocide additive that I add to the tank when refueling. It?s very expensive, but goes a long way. That liquid kills the algae over time. I will also need to replace the fuel filters at shorter intervals until the tank is clean. According to the shop, the engine manufacture doesn?t recommend routinely putting additives in the fuel, but this one does not damage the engine.

I suspect this is going to be more and more of an issue with the newer diesel fuel that is being supplied. If you own a rig with a diesel engine, it would be prudent to cut into the fuel filter when it is replaced and check for this contamination.

What you are putting into the tank WILL kill the algae but it will not get it out. The algae, now dead, will sink to the bottom of the tank, under the water that has separated from the diesel and stay there until it is cleaned out. (Same way the algae in a swimming pool works. When we returned from South Dakota earlier in the month the neighbor who was supposed to baby sit the pool did not. It was dark green with algae. I first had to pour the chemicals to it to kill the algae which sank to the bottom. I then spent several days vaccuming out the mess.)

On our way into Rapid City we lost power climbing the hills. Took it to the Cummins authorized shop and not only were both fuel filters clogged but the fuel lift pump had failed. I'm now fighting with Cummins because they denied warranty coverage for replacing the lift pump. There stance is the pump failed because of the clogged fuel filters. This coach is less than a year old and had less than 14,000 miles on it when this happened.

The repair guy in Rapid City, Eddie's Truck Sales/Service, says they are now recommending to all their diesel drivers that the fuel filters be changed out at 7,000 to 8,000 miles. My owners manual from Cummins, and the one for the coach from Monaco, says to change the filters at the time you change the oil/filter at 15,000 miles. The recommendation for the shorter interval appears to do with the new diesel fuel. (Some of the Monaco owners with older engines have experienced pump failures due to the new diesel causing the seals to leak. Cummins has said this is a problem with older engines but should not be a problem with engines built in the last "few" years with no definition of the word "few".)