Author Topic: overflowing injection pump  (Read 1841 times)

Big Yellow

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overflowing injection pump
« on: July 23, 2021, 14:12:41 »
Hi all,

I decided to check the injection pump oil levels for the first time myself. When removing the dipstick there was overflowing oil dripping to the floor, quite some amount. This was not good. The oil was relatively clean but seemed to have been overfilled dramatically...
My question is: Can there be any other reason for this overflowing from the dip stick hole, other that someone filled the pump up with far to much oil?

Thanks,

/ Vidar
Vidar "Big Yellow" Holmdin
MB 230 SL - 1964 manual

Pawel66

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Re: overflowing injection pump
« Reply #1 on: July 23, 2021, 14:42:25 »
Gasoline coming through? Did you smell it?
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

Shvegel

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Re: overflowing injection pump
« Reply #2 on: July 24, 2021, 04:18:58 »
Drain it, refill it, monitor the level.  If it rises again it is probably a really bad day.  There is a test procedure for pressure testing the pump off the car but you are most likely looking at replacing the barrels and pistons which are very expensive if you can find them.

scoot

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Re: overflowing injection pump
« Reply #3 on: July 24, 2021, 20:46:34 »
Can be gasoline leaking into the oil reservoir.  Not good.
Scott Allen
'67 250 SL (early)
Altadena, California

Paul99

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Re: overflowing injection pump
« Reply #4 on: July 25, 2021, 13:50:50 »
This has just happened to me as well this week.

Mine is the early pump with the dipstick. For the past 10 years I have checked it, perfect level.  This week it was 2 inches above the "full" mark. Took the surplus oil out, was dark - similar to engine oil colour.   No fuel in the oil that I could tell so engine oil is getting into the pump.

So, will send off for a rebuild I think. Anyone suggest a good UK based garage? Was thinking of Roger Edwards who rebuilt my engine.  They seem to know their stuff.

Paul.

kampala

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Re: overflowing injection pump
« Reply #5 on: July 25, 2021, 21:55:24 »
Paul

Not good that fluid is increasing  :-[ can you help explain why you think oil is feeding into the pump?  I was under the thinking that 230 injection pumps were isolated from engine oil?  Can you clarify?

250sl - later - manual
280sl - 1971 - Auto - LSD

Aslam

Paul99

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Re: overflowing injection pump
« Reply #6 on: July 26, 2021, 09:36:06 »
Oz,  So you are right, This is what I have found.  I spoke to these guys :  https://www.towerbridgediesels.co.uk/

Good for us UK based guys, not so for you I guess.

They said the small seals in the pump do eventually wear and oil will seep into the pump over time from the engine.  He suggests drain the oil, change it, monitor it, if the seals have failed fully the pump will fill with oil almost immediately and even overflow out of the pump after a few minutes of the engine running.  We might be lucky that its a minor leak and it refills over a longer time.  Either way its seal replacement time. 

Hope that helps.    To be fair, my pump is 55 years and 130k miles old so its fair that it starts to need some help.

Paul.