Finally got the car back together after it stalled and got a really bad brake fluid leak at the same time. I checked both filters and the strainer and it still acted like it was getting starved for fuel. No air in the lines either (replaced them all with clear ones.) Then I checked the oil in the pump, it was low but there was some in there. I topped it off and then the symptoms seamed to disappear. Car seems to be running fine now, don't think I damaged anything. My question now: can pump elements stick if they don't have sufficient lubrication? Or maybe the piston in the lift pump perhaps?

__________________
1973 220D ~135k Mi
1979 Ford F100 300 I6 - 225k Mi

The high pressure parts of the Elements are lubricated by the Fuel. In fact as time passes the Fuel leaks by the Element Plungers and dilutes the Oil in the Fuel Injection Pump.

However, if Water gets into the Fuel it is possible for the Element Plungers to stick rusted in the upwards position because there is only a spring to return it.

But, if you had a stuck plunger you would be able to tell by doing the Injector Cut Out test as no Fuel would come out of that Element.

__________________
84 300D, 82 Volvo 244Gl Diesel

In my opinion if adding oil to get the injection pump sump up to the proper level solved the problem. Then it is quite possible that little to no lubrication of the elements bores and pistons could if not actually stick a piston. Had some negative effect.

Certainly it might create enough drag to make it less than properly functional. All the oil should be drained and replaced as it gets contaminated with any fuel getting past the elements pistons. The piston to cylinder element is a honed fit. There is clearance but it is minimal. If the piston gets much hotter than the element walls it will drag. Get it really hot and it could possibly stick.

I would change the base oil more frequently on a really older injection pump. With the contained sump. Simply because the possibility of more leakage past the element pistons increases with time and use. Plus it takes so little oil to do this service.

Come to think of it there is another possible explanation. The oil viscosity available in the sump. May help seal older elements and pistons a little better. Certainly better than oil thinned out by fuel.

This thought is not totally subjective. It is based on a lot of experience in extending the lifespan of mechanical things with the proper application of lubricants. Even when common sense states things have moved well beyond the original manufactures recommendations or expectations.

Hype and merchandising care little other than the moving of products today. Do not use high milage engine oil for example. It can play havoc with oil seals. Only if say you have a leaking front seal for example.

Instead increase the viscosity grade if practical. The original factory recommendations are usually based on no existing wear. Unfortunatly in some cases incrementally increasing fuel milage seems to be the manufacturers justification. For using very low viscosity oils today.

Although with the low level of oil you found in the sump. Or the percentage of oil in it. The portion missing has gone somewhere. Once thinned down with time and ignoring the need to change it periodically it could become thin enough to escape faster by the pistons.

Find the recommended viscosity and put that in. If it was straight forty grade. As multi grades did not exist when that engine was made in the day. Use the single viscosity oil. Multi grade oils are not the same in many ways.


Then again when you added some new oil the viscosity was increased enough to aid in the pistons sealing perhaps. Restoring better function to the elements. To me it is anyone's guess but if changing and putting good proper oil in there periodically will handle the situation. That is all that counts.

Even with lubrication the elements in an injection pump get really hot from compressing the fuel. It is defined as core pump heat. It is claimed if the over flow or relief valve is working properly it removes some of this core heat with the returning fuel.

As said it is claimed. Personally I am not sure that is really the case but could easily be. . The primary heat transfer medium might be that lubricating oil in there. where the overflow of fuel is extracting the general heat of the pump that has been dispersed through it.

Sometimes the older paper blotter test can tell you a lot about the condition of a lubricant. You take a drop of the oil you want to test. Then a drop of new oil. Drop each on an a piece of blotter in separate locations. The spread of them can tell you quite a few things. Viscosity by comparison of the rate of spreading in comparison . Dirt content by the discoloration rings differentials. For just two of many examples.

Will really indicate an acid based water condition from condensation being present from little use on other than constant very short trips. My worst case was driving a car I had just acquired. A hundred and twenty miles home and boiling off two quarts of condensate in the process.

I know it is far from high tech but it is a far better tool than nothing. I also would use an oil that does not have a high detergent level in it. For the lubrication of that injection pump. Most straight cheap straight single viscosity oils will cover this whole scenario well enough.

I have no interest in oil threads. I do have interest in viscosities and detergent levels. Or the lack of them. It started simply before many of todays site members where even born.

Multi grade oils are not the same in many ways as are the single grade viscosity oils. So even if they have advantages. As in life there are trade offs to get them. Or more correctly almost all compromise situations have them. Or there really is nothing for free. Even if it seems so. Take your choice.

We for example get far more lifespan on the gas engines extracted now. Not because of improvements in lubricants primarily. Fuel injection reduces the cylinder wash down effect substantially. Is the primary reason. Carbs never gave equal fuel distribution to the cylinders.

At one time it was advisable to change the engine base oils every thousand to fifteen hundred miles. The oil was being thinned and contaminated at a much faster rate.

This was okay as a paid for oil and filter change was perhaps 10.00 or less. I remember buying gallons of engine base oil for a dollar a gallon and it was more expensive up here in Canada than in the good old USA.

I will not pay 150.00 to have the oil and filter changed in my modern diesel today. Call me cheap or whatever. It takes me perhaps fifteen minutes and thirty to forty dollars for the proper oil and filter. That reminds me you also get a junk filter in the 150.00 job.

I almost always had a good income stream and still do at 76 years of age. I should be averaging about 400.00 an hour for that paid for oil change that would justify the cost today.. I am not there.

Whatever time I have left is not going to be used to enhance and enlarge the large corporations ever growing excessive dominance of the service and retail sectors and bottom lines. I have no issue and never had with people making a dollar. What I see today is so different in many ways.

Oil itself never loses the ability to lubricate unless very high temperatures are experienced. Minimum of perhaps 450F degrees. . Then you go to real castor based oils in desperation.for a couple of hundred more degrees.

Turbo enhanced engines should not be shut down before a period to extract the extreme temperatures with the oil flow. That will develop otherwise in that trapped oil arounf the turbo bearings. Instead a cool down period at idle rpms should be employed first. Retaining the cooling oil flow through the bearings area.

This also reduces the potential of head cracks. Created differentials of hot spots boiling off the coolant in their immediate vicinity. Over time otherwise it can prove destructive. By creating repeating strong stress forces.

I am not alone in my geographical area with various practices. I picked up a lot of things from knowledgeable guys at earlier times. They where older than myself and now unfortunately are all gone.

Last but not least that base oil services the element piston to the injection pumps camshaft equivalent lobe. Excess wear has not been reported but the condition of the lobes may be checked for a pass by rebuilders. That oil supply serves the roller bearings at the ends of this lobe shaft as well. There have been reports of those bearing failing.

This whole scenario may be the reason the newer injection pumps on these engines went to a pressure fed oil feed system and return from the general engine supply.