As my title suggests, my injection pump is leaking. It's not a very large leak, but it is definitely leaking. It appears to be wet towards the bottom and on the engine side. I'm certain I can remove and replace what's there, but I don't want to go taking a bunch of stuff apart needlessly, particularly since show season is upon us. So where are the common leak points on these? Are there gaskets/seal sets available?

What is leaking?

On the older Fuel Injection pump on the side you are speaking of there is a drain tube.

In long use the Oil inside of the Fuel Injection Pump mixes with Fuel that leaks by the Elements and the fluid level rises and it leaks out.

Find a thread that tells you how to get the Oil/Fluid out of the Fuel Injection Pump; do that and refill it with Oil.

If only Oil comes out then you know that Oil is coming out of that Drain Tube that keeps the Pump from being overfilled with Oil.

If it is Fuel Leaking from the Top of the Fuel Injection Pump it is likely the O-rings and Crush Washers will need to be changed. Look for instructions on doing that on M type Fuel Injection Pumps.

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84 300D, 82 Volvo 244Gl Diesel

thanks, I wasn't aware that there was a drain tube there, but I did know enough (thanks only to this forum) to oil the pump. I opened the drain plug not long after I got the car, and nothing came out. It took about a half a quart of oil to fill it. I haven't checked it again but I will. I'm pretty sure it's fuel that is leaking. I get about three good sized drops on the ground when I park it after a few miles on the highway. It's dripping off the cross member and I haven't been able to find the source.

wipe it down and then put something white under the car when you park to confirm whether it is motor oil or fuel. that will inform what needs to be tightened or replaced.

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'77 240D, 504H, OM617.952, etc.

It's definitely fuel. I can smell it. It settles to the bottom of the cross member and drips from there.

this is probably not in the FSM, but what i would do is clean off the IP, tie some clean rag scraps around the various places fuel comes in and out, go for a drive and hope find the origin of the leak that way.

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'77 240D, 504H, OM617.952, etc.

That's a great idea, I'm going to do that the next time I drive it, thanks.

Drat and I was about to say do the bog roll test!

(Kind of beat me to it)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Did anyone ever discover the source of the diesel leak? I an having the same problem.

If it is on this vehicle 1976 W115 240D the only external leak I can think of is the O-ring or rings on the Delivery Valve Holders. That is at the top of the Pump and degreasing the pump and taking it for a drive and looking to see where the leak is coming from will tell you where the leak is.

Fuel can leak out of the older style hand primers and that would also be external.

Internal leaks can come from the Fuel Supply/Lift Pump from the little 5mm O-ring inside of the pump that keeps the Oil in the Fuel Injection Pump sump away from the Diesel Fuel inside of the Fuel Supply/Lift Pump. The short story is it can leak diesel fuel into the Fuel Injection Pump Oil sump and that will mix with the Oil and the level will rise and it will drip out of that tube mentioned in the previous post in this threads.

Another way Diesel Fuel gets into the sump is if the Elements/Plungers and Barrels are worn a tiny bit of fuel passes around them down into the Oil sump inside of the Fuel Injection Pump Oil sump and the level rises and it leaks out of the drain tube.

The oil sump drain tube is within the read circle in the attached picture.

If you go to a Mercedes parts site it will show an exploded view of the fuel injection pump and the part numbers of what is available. Other then that you need to look at the number plate and go to a bosch certified place for the parts of do you research and go to eBay and so on.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel