oil filling up in fuel injection pump why?

[markh]

hello i have a 1965 230sl and noticed the other day an oil leak coming from fuel injection pump,i noticed that the pump has an oil feed line from engine supplying engine oil but it also as a little dip stick at back of pump and when i took the stick out it was full to the top, if it is being fed automatically why need for dip stick. how does the oil return from pump? also does it need this auto feed can it just be topped up manually as its not returning where ever any way. can any one help  regards markh

[scoot]

Hi Mark -

If it's the same as my early 250 SL, it isn't filling up with oil.  It's filling up with gas that is mixing with the oil and raising the level.  The earlier injection pumps have their own oil reservoir with a little dipstick that is hard to find (but you found that) and a cap to add oil (red) on the top.  It's a closed system - no contact with the engine oil.  What I think happens is that the gobs of gas flowing through the thing leak past seals that are old and get into the oil, just causing the level to rise.  Mine rose to the point of coming out of the red cap.

I was told to try changing the oil and it might help (I don't know why) so I did.  The manual says how much oil to add.  There is not a drain plug - to remove the oil you need to suck it out of the injection pump.  I know of two ways to do this.  One is to use an old Windex pump and cram it down to the bottom and pump for ages until all of the oil comes out.  The other is to use a syringe -- I have one for this but haven't had the joy of trying this yet.   Mine does this fairly slowly and I'm just living with it for now, but I'm pretty sure that this requires a pump rebuild to fix, and that if left untreated it could cause more damage to the pump (the oil is oil for a reason).

I probably got some of the technical stuff wrong here but this is what I think is the case with my car.  Someone who knows more will correct this and put in a better / more accurate answer probably...

Scott

[markh]

this pump as got an oil feed line from engine and the pump as been recently over hauled and it is definitely oil and not petrol

[ja17]

Hello Mark,

All the pumps have oil lines connecting from the rear. Only the later pumps circulate engine oil and seek the correct oil level automatically.  On the early pumps the oil line enters the IP in a different area and supplies oil just to the IP cylinders where it provides a seal just like piston rings do in your engine. This oil does not enter the "lower sump" aof the IP. 

In the later pumps the oil line enters an area which allows oil to lubricate the IP and ciculate into the lower  sump and then back into the engine.

Look in the injection pump tour to see more detail and photos of both.

[markh]

hi ja 17
i understand what your saying but why is the back filling up with oil ? why is it not returning mine looks to be a later pump is this a fault in the pump this is all i really want to know, as the pump repairer ballsed it up

[scoot]

I'm very confused.  So Mark's pump has oil coming from the engine that is separate from the oil in the injection pump sump (separate from the red cap to fill and the little dipstick to check)?    Not to hijack Mark's thread, but if the oil level (or oil and gas) is rising in my injection pump is it possible that I was complete incorrect about what I wrote above and that I don't have something that requires a re-build?

[Peter van Es]

Have you read: http://www.sl113.org/wiki/Fuel/Injection as Joe suggested?

It explains about the two different kinds of injection pump.

Peter

[Naj ✝︎]

Check the oil line from the engine block to the FIP. There should be an in-line valve on it (9). It may be stuck open with debris etc.
naj

[jameshoward]

Markh,

After reading the Wiki, do a couple of searches on the forum. There is a TON of info on here about the pumps, how they fill up, and with what (in your case it may be petrol). You'll develop a great sense of understanding about the pump by reading around the issue. Ask me how I know! (You'll find my posts going over exactly the same issue, which required me to send off the pump for some mods).

The search tool is excellent - give it a go.

In the interim, remove the old oil, put in new oil, and monitor the levels. Don't drive it with the levels overflowing. You may also find that with the level correct, you'll get vastly improved MPG.

JH

[markh]

here we go again the pump is filling with oil and not petrol and is leaking on garage floor if it was petrol it would evap away, i have just wiped oil up again. i wiped up the pool of oil last week car not been run and theres another pool of oil a week later.had a quick look at pump tour but could not find much info on oil lub.this looks to be the later type ip but why have i got a dip stick.
surly if oil line valve is stuck open it would still have to return on this forced system.
have i got this right is mine a later pump i am only going by if having one solenoid on the back

[Naj ✝︎]

What is the pump # on the tag?

PES6KLxxxxxxxxxxxxxxxxx

naj

[markh]

  hi pump no  pes6kl70/120r11 50406300 spoke to guy who removed pump last time he says there was no drain hole

[Dash808]

here we go again the pump is filling with oil and not petrol and is leaking on garage floor if it was petrol it would evap away,

It would evaporate if it were only gas.   

What everyone is saying is some gas may be leaking into your pump, hence your full condition.  The gas is mixing with the oil and leaking out so it wouldn't necessarily evaporate away and you are left thinking it is 100% oil.   

Not saying that is your problem, but it seems to be the majority of the problems when this happens.

[Naj ✝︎]

  hi pump no  pes6kl70/120r11 50406300 spoke to guy who removed pump last time he says there was no drain hole

Seems you've got the right pump.

Is the valve there?

naj

[markh]

hi so are you saying mine is the later pump as i thought.  The valve that you mentioned do you mean the valve which regulates oil to pump this as been checked and was told it was OK
as for this oil  petrol thing it is oil that is leaking out of the pump if there is fuel i it is so slight but my original question as not been answered why it is doing this and is the pump at fault as this pump as been over hauled

[scoot]

Just as a clarification, in my situation it has never been petrol leaking out of the injector pump - it is that gas would leak into the oil in the injector pump causing the oil level to rise, eventually causing it to overflow the fill cap. 

[hands_aus]

The Inj pump drive shaft goes through the plunger section to the rear where the govenor weights are located.

There must be a seal between the reservoir and the plunger section that is fed by the line from the engine.

It seems possible THAT seal is leaking oil.

[richard230sl]

I am interested in the valve for the oil supply on the FI pump that the  NAJ describes (in his attached picture indicated with the no 9)
Can anyone explain to me how this valve works and when it should close?
Any tips for opening this valve and cleaning it?

Thanks

Richard

[richard230sl]

In addition to my post above:

I am wondering if the mentioned valve is stuck, is it a possible cause for a rising oil level in the FI pump?
In other words: will the pressure of a correct oil level in the IP (with  a well functioning valve) be enough to close this valve and make sure that the oil supply is blocked?

I am still hoping there is a cure to fix my rising oil level problem (it is only oil, no fuel...) without completely overhauling the pump.

Thanks

Richard

[Benz Dr.]

The valve in the oil line is a check valve, meaning it only allows flow in one direction which is towards the IP in this case. This check valve is placed in the oil line to prevent fuel from backing up into the engine oil at idle speed if your oil pressure drops below 10 PSI ( I'm not sure of the exact number but it's not very much ) If your engine only has that much oil pressure at idle, you're already in for an engine rebuild.

You can remove the check valve from the line and then take it apart for inspection and cleaning. The valve should open with very little pressure and should not bind or stick. I saw a case where one was stuck ( rust ) in the closed position and it ruined the IP.

This check valve has nothing to do with the oil level in your pump. Faulty seals that should be holding fuel from leaking into the crank case of the IP are worn and allowing small amounts to leak by. Over time this will cause the oil level to rise. Trust us, if your oil level keeps rising, it's due to bad seals and won't get better. The oil in your IP will be diluted with fuel, I'm sure of that. Or, someone added more oil to your IP because they thought it seemed like the right thing to do.
 Remove all of this oil, fill it to the correct level, and keep a close eye on it ( like every 100 miles or less ) to see if it continues to rise. If it does, have the pump rebuilt.

[garymand]

Hi Mark, I think I understand what you are saying.  From this dialog, there appears to be 3 types of FIPs: 230s with a oil supply from the motor, 250 and early 280 with a red oil fill c/breather cap and no oil supply from the motor, and late 280 that went back to oil supplied from the motor.  I've had types 2 and 3 FIPs but not the early 230. My pump housings are like the drawing with gas fittings on the outof the piston housing, while the 230 picture shows something other with gas fittings on the motor side AND an oil supply line. 

I have tried to understand how they work. I could be wrong, but I assumed that in the old pumps (230 and 250) , the piston case did not share oil with the motor. It has its own private reserve of oil shared by both the regulator and the piston housings. I assumed the dipstick measured the common level through the whole pump, but I see in the above picture there is an oil delivery line, hard to see.  (The circle really circles the gas fitting)  It is the small 3-4mm tube heading past the distributor.  If that is the case, that your FIP is supplied with engine oil, the excess oil drains out through a hole in the front of the pump.  The height of the hole establishes the level of the oil in the pump.  That is how it works on the 280 FIPs.  I could be wrong, I though my 250 had no drain hole and no engine oil supply and the whole FIP shared the same pool of oil and a red plastic breather/filler cap.

So, somewhere in this is the answer to your pump oil level problem.  It either has a oil supply line and no outlet hole or its blocked by the gasket.  THEN it is not self-leveling and it will continue to overfill the oil level and leak from somewhere.  Or, If it has no oil supply line and it is overfilling, where but from gas leaks past the pumps would the extra fluid come from?  And I would assume it would dilute and smell of gas, which you insist is not the case.  You said it has the dip stick, why would it have a dipstick if it has an oil supply from the motor?

Sounds like you need to talk to your FIP man.  Either way, it didn't do it before, right?  What did he do to your pump? 

[Benz Dr.]

Uh.........no. There are two types. The first version has it's own crankcase and you , the owner, should check it once in a while using the dip stick provided.

The second version is a flow through design that finds its own level and any extra oil returns back to the oil pan. This version will have a longer oil line without any check valve. The oil hole at the drive end of the IP won't be blocked by the gaskets because it's designed to flow through inside of this area and the spacer block. Both versions use the same gaskets and parts for mounting.