Overfilled injection pump oil reservoir

[hughet]

I have a 230 SL (113 042 10 05155) with the old style injection pump which has its own oil reservoir and a dipstick.
While checking out my injection pump oil level I noticed that it had become overfilled by about 8 ounces. It used to be at the correct level. To fix it I sucked all of the oil (around 16 ounces) out with a Mityvac and added about 8 ounces of fresh oil until the oil level was at the line in the dipstick.
My question is...What is happening inside the injection pump which causes the oil level in the pump to increase? Is gasoline leaking past a seal in the pump and getting into the oil? Is this a big problem and if so how do you fix it?

Tom Hughes
St. Louis MO

[Benz Dr.]

Yeah, it's leaking.
 The extra oil ( or mixture of oil and gas ) slows the action of the governor fly weights. Really diluted oil can't be good for all the moving parts inside of the pump.
Pretty common problem.

Daniel G Caron

[graphic66]

OK Doc you have diagnosed the illness, whats the prognosis. Will this require major surgery with Anesthesia or is this a simple in office procedure. I also have these same symtoms in my 230SL. I have been very careful with it's diet, no rusty buildup, lots of exercise, and a recent transplant with a new pump. Please Doc tell me the patient will make it.

[Benz Dr.]

The patient is sick but not going to die ( I think )
 I had a pump fail once and it quickly filled the crankcase with gas. Even though I had fresh oil in the engine it had 2 liters more in it after only 10 miles of driving. Oil was coming out every crack and seal on the engine and everything was smoking heavily. I'm not sure if this would be caught in time driving at night because you wouldn't see all the smoke coming out the tail pipe. I burned up my engine at night when I ran it out of water 2 years ago. Driving by smell is just as important as by sounds.

Anyway, back to your question;
 Keep an eye on how fast the oil level is rising on the dip stick. If it fills up quickly ( 500 miles ) you better get it looked at. The pump will need to be rebuilt but should still be in good shape unless it was driven this way for a long time. Fuel diluted oil will wear parts out inside the pump.

Daniel G Caron

[n/a]

your problem can be fixed,if you would like to give me a
call at 631-589-1600 and ask for Hans i would be more
than happy to help

[hughet]

Thanks for the responses, guys. I just talked to Hans and it sounds like I've got a summer project on my hands. He says that an o ring has dried up which is causing gas to leak through to the oil reservoir.

The car runs great but has a few problems. It burns oil and it has gotten to the point that I cannot adjust the valves properly. The lowest smooth idle I can get is around 1200 and it runs rich.
So at a minimum I am looking at a cylinder head overhaul and that would be a good time to send the injection pump off to get it redone.

I bought the car over 15 years ago and did an overhaul on the motor because it leaked oil and ran poorly. When I got it apart, I found that it had been recently overhauled by a mechanic of marginal competence. It had first oversize pistons and first undersize bearings and the cylinders and journals miked out just fine. The reason it ran so bad was that the injection pump was advanced around 22 degrees and the cam was retarded around 20 degrees. It is hard to believe that it ran at all!  It leaked oil because the guy had failed to change the rope seal at the back of the crankshaft (or he did it improperly)

I am a good enough mechanic to assemble and disassemble the motor correctly but what I found was that an overhaul is only as good as the machine shop you are using.

I guess that if I had used a top notch machine shop then the valves and guides and seats would have been replaced correctly and I would not be facing another redo. But then again, my wife and kids and I have been tooting around the neighborhood for 15 years and those short trips put a lot of wear and tear on a car. This time I will send the head or whole motor out to someplace like Metric that does it right and cuts no corners.
Any recommendations?
I'll keep you posted on what I do.
Tom Hughes
St. Louis MO

[J. Huber]

Hughet, could you keep us posted on how you tackle this one. Good luck.

I checked my level once, maybe a year or so ago and I noticed it was over-filled. I basically turned a blind-eye to it, assuming it would be ok. (I have been in one of those "don't touch anything because its running so good" modes...) Probably not the best idea. Perhaps I should siphon it to level and see if it fills back-up. Would a turkey baster work?

James
63 230SL

[rwmastel]

quote:Originally posted by J. Huber

Probably not the best idea. Perhaps I should siphon it to level and see if it fills back-up. Would a turkey baster work?

James,
Absolutely!  When I bought my car, I check this and when opening the dip stick the stuff (oil/fuel mix) just ran out like it was under pressure.  Made a puddle about 10 inches across on the garage floor!  I pumped everything out using an old Windex bottle pump and then put in the correct amount (180ml or so?) of engine oil.  It has not gone back up.

Tom,
Perhaps your dried seal can be fixed by regular use?  How many miles per year do you drive?

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[hughet]

James, You need a thin rigid tube that goes down to the bottom of the reservoir. I used plastic tubing and vacuum line left over from a 300SD project along with a mityvac. A windex bottle pump will probably work fine. I sucked all of the oil out and replaced it because I figured that it was diluted and would not lubricate well. It runs better now.

Rod, I do drive the car a couple times a week but I am not holding out much hope for improvement in the leaking o ring. The injection system runs too rich and won't idle well below 1200. The cold start valve is OK and I have messed with the idle screw and the throttle linkage to no avail. It has been about 15 years since I bought the pump and I am not sure that it was ever right. It is about time to go through the whole injection system anyway.

In the meantime I will let you guys know how fast it is leaking.

[J. Huber]

Thanks. Considering I don't even own a Turkey Baster, I'll find a windex bottle...

Any recommendations on the best oil to go in there? And to fill, I am presuming it goes in where the large red cap is? Amount?

James
63 230SL

[rwmastel]

James,
I think it goes in where the dip stick is.  Not sure since I don't have a red cap!  Anyone know what goes under the red cap?  I used my regular engine oil (10w30 at the time).

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[hands_aus]

James
Use the hole under the red cap. Capacity is about 180ml engine oil, mineral oil..usually 20W50

A small funnel would work, I use a hospital cup with a lid (with a 0.5" spout that fits a drinking straw).

hughet
A point to remember.. the flyweight springs of the govenor in the injection pump generally do NOT spin in the oil. If the oil level is too high you will have great difficulty adjusting the air fuel mixture to give the correct exhaust CO level of 3.5-4.5% at IDLE.
Once you have the oil level normal try re-adjusting the air/fuel mixture... you might be pleasantly surprised.

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Benz Dr.]

I'd be inclined NOT to use a really heavy oil in the ingection pump. 10W30 or 10W40 would be plenty.
 I've also been told not to use STP or let it get anywhere near the pump.  My pump guy said it can damage the internal seals.

Daniel G Caron

[jameshoward]

My FI pump is taking on petrol, it seems. I recently checked the oil level and a considerable amount of oil flowed out making a large puddle on the floor.  It smelled a lot of petrol and was pretty crappy.

I've since emptied it and refilled it as mentioned in this post. However, on checking it again today, I see that the level has risen and again the oil smells of petrol. I suppose it's very unwell indeed.

I wondered if anyone involved in this original post had anything else to add about how the problem was solved? I note Doc Benz said the pump needs to be rebuilt. If anyone in the UK or Europe could recommend a place and provide an idea of cost, I'd be grateful.

If it's the O ring seal which is at fault, as mentioned in this post, can the replacement be done without sending the FI pump away? (Tom Huges - your experiences would be informative if you could offer them!)

Thanks for any help.

James

[German Dude]

Hi James,

assuming you would prefer a German address (shipping), do you know
Koller & Schwemmer in Nuremberg?
Check out www.koller.de.

They are a Bosch Classic Center. On their homepage they claim to have purchased the original Bosch and Kugelfischer mechanical injection pump manufacturing lines. The site is pretty impressive.

Good luck,



Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon