Ford Lehman Diesel Oil And Filter Change

After a 1,200-mile-plus cruise, engine maintenance is not a to do, it is rather a must do. We did take the opportunity to change oil and filters at the halfway mark, but a thorough change of all filters, as well as an oil change, was high on our list. So I thought I would share the experience with you and give you some insight on how we approach this sometimes messy chore.

An attempt to clean the gunk out of the bowl in the Racor 500 filter housing resulted in a stripped thread on one of the bolts that attaches the bowl to the housing. Of course, that resulted in the filter housing leaking diesel into the bilge, aft of the engine, so a replacement was required. As luck would have it, we purchased all of the parts to install a fuel-polishing system for the engine and have been carrying all of the parts with us for several months now. A new Racor filter housing was sitting in a box waiting to be installed, including all of the needed fittings and replacement 5/16 fuel lines. With the housing replaced, a section of the copper fuel line, from where it was attached at the old filter to the tee that connects both of our fuel tanks, was also replaced. I had not planned to start this yet, but at least all of the material was on hand. Once the housing and lines were installed, the filter was filled with clean diesel fuel. I prefer to fill the filter from a small container rather than try and fill it using the engine's fuel pump. Before securing the lid, all of the new gaskets in the lid are wetted down with some diesel fuel. I use a generous number of oil absorbent pads under all of the areas I am working on to keep the fuel and oil out of the bilge and from getting all over everything.

Next, I turned my attention to the secondary fuel filters on the engine. These are twin filters and are the original style that comes with the Ford Lehman 120. To remove the filter, a plastic knob on the bottom of the housing is removed. At the same time, the securing bolts on the top of the filter is removed. With this, the filter and the bottom section or the "bowl" is removed. There are gaskets inside both the lower section and the upper mount that must be removed, as well as a small O-ring at the head of the securing bolt. Here is where problems can sometimes arise. If you look closely, you will see that the two sealing rigs or gaskets are not the same size if you are using the correct filter elements. Be sure that the slightly smaller one goes into the bottom, or the "bowl," and the larger one in the top. If they are reversed, chances are good that you will have a leak and have to start all over again. Wet each of the gaskets and O-rings with diesel before re-installing them. Slide the securing bolt back on, slide the filter element over the securing bolt, slide on the bottom section, and tighten the securing bolt until everything is nice and snug. Be careful and don't over-tighten. Now move on to the send filter if you have the dual unit.

The engine instructions say to use the fuel lift pump to bleed the engine before starting. This can be time consuming and tedious and I have not had to do that with any of the filter changes. What I have done instead is to remove the bleed screw from the top of both housings. I have a small funnel that will fit in the hole for the bleed screws. I fill the filters from a small container until fuel runs out the top of BOTH housings. Then, the bleed screws are reattached. Once both filters are full, I can start the engine, check for leaks and make sure there is no air in the system. At this point, the engine is run long enough to bring it up to temperature. This is in preparation for the oil change and makes the oil flow better for removal. It generally takes about 20 minutes of running to be sure there are no fuel or air leaks and to get the temperature up.

Once the engine is shut down, the first thing I do is to replace the filter. This is also the messy part, but the spillage can be minimal. The first thing I do is to take a screwdriver and punch a hole in the top of the filter. No, you did not read that wrong. This will allow most of the oil in the filter to drain back into the engine and leave only a small amount to spill once the filter is removed.

Our filter is mounted on a small L-shaped bracket, and by loosening that bracket, I can rotate the filter so it is turned on its side. This allows me to catch all of the oil rather than having it spread out and leak from under the entire filter housing. Here, too, I put oil absorbent pads under everything.

The bolt in the bracket is tightened just a bit to hold the filter in this position.

The next step is to loosen the filter. For this, I like to use an adjustable strap wrench and just use it to break the filter loose. The filter can be removed the rest of the way by hand. I like to wear vinyl disposable gloves to keep my hands clean during the process.

With the filter just loose, it should not yet drip any oil. I use plastic sandwich bags big enough to hold the filter to also catch most of the oil that is still in the filter. By placing it just under the bracket, I can accomplish this.

Once the filter is removed, it is placed in the sandwich bag and sealed to keep from spilling. It can then be disposed of properly without making any more of a mess.

The housing is wiped down and is ready for the new filter. Before attaching the filter, the O-ring is wetted with engine oil to help it seal and get the filter back on by hand tightening. I never use the strap wrench to tighten the filter. The L-bracket is loosened and returned to its original position.

The filter part of the change is done and now the oil has to be removed.

Have I mentioned how much I really, really like our X-change-r oil changing pump. Our oil changes have gone from a messy, time-consuming chore to a quick and easy maintenance item. The reversible pump on the Model 912 allows the oil to be drawn out of the bottom of the sump via an attached line in the bottom drain in a matter of a couple of minutes. Remember to warm the engine up to temperature before extracting the oil.

With the dedicated line from the X-change-r in an empty oil container, a flip of the switch draws the old oil into it, and in a matter of a couple of minutes total, all three gallons of the 30-weight oil is extracted from the crankcase. No mess, no fuss and no spilled oil to clean up. We do keep oil absorbent pads on hand just in case there is an accident. This is a boat so stuff happens.

With all three gallons extracted, the process is reversed, and with a flip of the switch on the changer pump in the opposite direction, the new oil is pumped into the crankcase. Once again, this is accomplished in a matter of a few minutes and there is no oil spilled on the engine or anywhere else. The exact amount is added drawing from three one-gallon containers. Once finished, the pump is shut down and the empty oil jugs are saved for the next change. We always dispose of the old oil in a recycle drum. Most marinas now have these, or you can take it to an auto repair shop.

The next item is changing the oil in the fuel-injector pump. This is something different for us as our former Yanmar and Perkins engines did not require this. According to Bob Smith at American Diesel, and our engine manual, this oil should be changed every 50 hours. I have to admit, we have not stuck to the 50-hour schedule, and it get changed about every 100 hours. We have been told that if the engine begins to idle rough, it might be an indicator that the oil needs changing.

The first step is to remove the fill plug at the top of the pump. Be careful not to mess up the slot in the plug. It has been recommended by some that O-rings be put in each of these plugs and replaced each time the oil is changed. Our pump has copper washers in each plug.

Next, the overflow plug has to be removed. If a lot of fluid comes out when the plug is removed, you probably waited to long to change the oil or you have other problems and fuel is mixing with the oil. This plug plays a part in the filling process.

The drain plug is on the bottom forward section of the pump. This is directly over the raw-water pump and there is not a lot of room to place something to catch the oil. We loosen the plug just a bit, but  it does not leak oil until it is loosened quite a bit. Here, an absorbent pad is a must since it is really hard not to spill a bit.

I use a small Tupperware container that is just small enough to fit between the injector pump and the water pump which will hold all of the oil from the injector pump. It also gives me enough room to finish removal of the drain plug. Once it is completely drained, the container is carefully removed and the drain plug replaced. With the small funnel I use to fill the fuel filters, the pumped is filled with oil until it runs out the overflow in the side of the pump. The plug is replaced for the overflow and the filler plug in the top of the pump is also reinstalled. After a good wipe down of everything, the engine is ready to be restarted. With the engine running, the oil and fuel filters are all checked for leaks as well as the plugs in the injector pump. If all is well, the engine can be shut down, the final clean up done and we are ready for more fun with the boat. No muss, no fuss.