OM616 delivery valve seals (or something else leaking?) - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 05-28-2011, 07:41 PM

After spending most of the spring enjoying the results of my hard work on the 300D, I've decided I need a new project or two ... so I'm trying to resurrect the 78 240D, again. It starts fine and drives fine, but the idle is pretty dreadful and there's a heck of a lot leaking, including fuel I can see running down the front of the injection pump. I can't see any on top of the pump, but my guess is delivery valve seals, because I can't figure how fuel would get on that part of the pump from anywhere else (or I suppose it could be the line leaking). Since the seal rings are cheap, would that be a reasonable place to start? Or am I missing something obvious?
If I do the delivery valve seals, am I correct in concluding from searches that there is only a copper washer involved, and not the rubber seal that's in some other engine's pumps?

aaa · #2 05-29-2011, 05:51 AM

They don't use rubber seals so they don't leak very often. I would look elsewhere first.

Photo?

Diesel911 · #3 05-29-2011, 10:18 AM

Dose your Fuel Injection Pump have a pneumatic (it will have a tube or hose going to the Intake Manifold to the rear of the Fuel Injection pump) or Mechanical Governor?

You are going to have to find some way to view where the leak is. A small Mirror like they sell in the Tools section might work.

The other way is to degrease everything so it is nice and dry and start feeling around with your Carefully with Fingers.
Don't feel around like that if the Fuel is spurting out under presser or it can inject into your skin.
Perhaps run the Engine a bit and shut it off and feel working your way from the top down.

BodhiBenz1987 · #4 05-29-2011, 12:25 PM

Quote:

Originally Posted by Diesel911

Dose your Fuel Injection Pump have a pneumatic (it will have a tube or hose going to the Intake Manifold to the rear of the Fuel Injection pump) or Mechanical Governor?

You are going to have to find some way to view where the leak is. A small Mirror like they sell in the Tools section might work.

The other way is to degrease everything so it is nice and dry and start feeling around with your Carefully with Fingers.
Don't feel around like that if the Fuel is spurting out under presser or it can inject into your skin.
Perhaps run the Engine a bit and shut it off and feel working your way from the top down.

I am pretty sure it does not have the tube you mention, but I'll have to double check. I think the degreasing is a must to find out any more. This car has 366k miles of crud built up pretty much everywhere so it's making it harder to tell what's actually leaking where. I'll report back after making a gross mess in the driveway!

Diesel911 · #5 05-29-2011, 12:40 PM

If you have an Feul Injection Pump that has a 13mm Nuts on each side of the Delivery Valve Holder (this is an MW Fuel Injection Pump) do not loosen them as that is where they pre-adjust the Fuel amount when the Fuel Injection Pump was on the Test stand.

BodhiBenz1987 · #6 05-29-2011, 08:17 PM

Thanks for the heads-up on the 13mm bolts, diesel911.

Well, now I'm really confused. I spent about an hour cleaning the engine bay, if not more time, and it's still grimy, but I can see a little better. And the fuel seems to be coming from the front of the pump itself. I attached photos. In the top circular indent, there's a little pinhole ... which fuel is either coming out of, or has gotten into. Is that hole supposed to be there? What is it?

Diesel911 · #7 05-29-2011, 11:59 PM

Quote:

Originally Posted by BodhiBenz1987

Thanks for the heads-up on the 13mm bolts, diesel911.

Well, now I'm really confused. I spent about an hour cleaning the engine bay, if not more time, and it's still grimy, but I can see a little better. And the fuel seems to be coming from the front of the pump itself. I attached photos. In the top circular indent, there's a little pinhole ... which fuel is either coming out of, or has gotten into. Is that hole supposed to be there? What is it?

Those are Core Plugs used to cover up holes; similar to the Core/Freeze plugs in the Engine.
In your case the Core Plug has rusted through and you have a hole in it.

I think you have 2 choices. One would be to take the Fuel Injection Pump to a Bosch Fuel Injection Shop and have them change Plug.

The other is to drain the Fuel out of the Fue Injection Pump Housing. Get a wire brush in there and get out as much rust as you can.
Degrease the whole cavity formed by the Core Plug with Brake Cleaner so it is absolutely dry and apply a heat resistant Epoxy like JB weld to seal off the hole.

I would let the JB Weld cure and repeat the same 2 or more times.

Another Alternative would be to do the Cleaning and apply some Epoxy Putty and fill the complete cavity or us a combination of both the JB Weld and the Epoxy Putty to fill the complete cavity of the Plug.

The Epoxy Putty has to be able to handle the heat or it will fall off and leak again. Although the Fuel Injection pump dose not get as hot as some of the other Engine parts.

BodhiBenz1987 · #8 05-30-2011, 02:46 AM

Yikes ... that's kind of a bummer but not surprising on this car. The plug surface is all lumpy, so I'm wondering if someone has maybe already done an epoxy job and it broke through. I had no idea that was an area that could rust through like that.

I also wasn't really aware of what engine freeze plugs were, but I just did a search and I'm pretty sure now that that's where my coolant leak is (yeah, everything's leaking) ... at least it looks I can change those out.

Diesel911 · #9 05-30-2011, 09:38 AM

The Plugs on the Fuel Injection Pump are not only thin Steel they are rather Soft Steel. This may be because they are pressed into an Aluminum Housing and the plug has to bend to fit the hole without enough pressure around it to crack the Aluminum Housing.

I have lived here in Southern California all of my life and am not used to the amount of rust I have seen in the photos east cost Folks Post.

Now when I worked at the Navel Shipyard I sometimes worked on badly rusted things due to the Salty Sea Air.

I had to get rid of my Lower Control Arms due to heavy rust (My Car came from the East Cost). When I beat the thick rust off the Hole for the Bushing in the Rod was too enlarged for me to re-use it.

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BodhiBenz1987 · #10 05-31-2011, 08:30 PM

Quote:

Originally Posted by Diesel911

The Plugs on the Fuel Injection Pump are not only thin Steel they are rather Soft Steel. This may be because they are pressed into an Aluminum Housing and the plug has to bend to fit the hole without enough pressure around it to crack the Aluminum Housing.

So is this something that happens often (relatively, that is)? I can't find anything similar in a search. Which approach do you think would be better? Obviously removing the pump would be more labor-intensive, but if a JB Weld fix doesn't work I might just make it worse, no? I think it may already has an epoxy on it (I got this car two years ago so who knows what the last owner did). Not for the first time, this car has torn on how much money I want to spend ...

aaa · #11 05-31-2011, 08:51 PM

If you're gonna remove the pump you may as well grab a replacement from the junkyard, far cheaper. $30 iirc.

Try the jbweld first, then plot a JY trip.

layback40 · #12 05-31-2011, 08:54 PM

Quote:

Originally Posted by aaa

If you're gonna remove the pump you may as well grab a replacement from the junkyard, far cheaper. $30 iirc.

Try the jbweld first, then plot a JY trip.

X2
JB it first without removing the IP. If that doesnt work, then its a toss up as to if you wish to try & remove clean & replace the old plug with the IP in place or do a swap.

BodhiBenz1987 · #13 06-01-2011, 05:17 PM

Thanks guys. I'll give the clean and JB Weld a try as soon as I get a little chunk of free time. Dumb question: How does one drain the IP housing? Remove one of the hollow bolts? When I'm done and it's cured, I'm assuming just priming away will fill it back up?

Now the car is leaking coolant fairly profusely from either the head or the t-stat housing (originally I thought it was a core plug but there isn't one in that area that I can see) ... so this is going to be a work in progress ...

layback40 · #14 06-01-2011, 09:12 PM

Quote:

Originally Posted by BodhiBenz1987

Thanks guys. I'll give the clean and JB Weld a try as soon as I get a little chunk of free time. Dumb question: How does one drain the IP housing? Remove one of the hollow bolts? When I'm done and it's cured, I'm assuming just priming away will fill it back up?

Now the car is leaking coolant fairly profusely from either the head or the t-stat housing (originally I thought it was a core plug but there isn't one in that area that I can see) ... so this is going to be a work in progress ...

There should be a drain plug some where on the IP.

Pray its not the head !!!

The housing is sacrificial to protect the motor. Do not try & repair if its corroded, just replace it. Never coat the inside of any alloy component like a t-stat housing that contains coolant.

BodhiBenz1987 · #15 06-01-2011, 10:07 PM

Quote:

Originally Posted by layback40

There should be a drain plug some where on the IP.

Pray its not the head !!!

The housing is sacrificial to protect the motor. Do not try & repair if its corroded, just replace it. Never coat the inside of any alloy component like a t-stat housing that contains coolant.

Yeah I'd definitely rather it not be coming out of the head.

There was no coolant in oil 1,000 miles ago but I guess that does not rule out external coolant leak from the gasket. The t-stat housing is one of the few things unlikely to be corroded due to the large amounts of oil on the bottom of it, I think. There is a gasket between it and the block, which I bought for like $2, but I'm not sure if that's what's leaking or not.

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