Can't stop oil leak!!!

H

Hillrod660

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Jan 11, 2016
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45
I'm leaking oil from where the injection pump mounts to the case, I've had this pump out 4 times, changed orings, used silicone. I've slowed it down but it still leaks. I'm beating my head against the wall. Then sometimes I'll it will hardly leak. The only thing I can think of is the valve cover breathers are not venting my crankcase pressure fast enough, causing it to push oil out past the oring. (i do not have the tappet cover breathers) or I have a defective case from cummins that's not letting it seal up. I'm out of Ideas and need some help! I do not have a tappet breather so I don't know of that's cause excess case pressure. I'm half tempest to find a used case and swap it out and try that. I'm hoping it's not the pump, like a defect in the casting. It's a p pumped 24v but I'm posting here cuz it's the 12v pump and case so I thought I'd get a little better fed back. Any help would be greatly appreciated,
 
Are you sure its not the tappet cover gasket leaking from that area? i never have issues with that leaking oil but the tappet cover will be in that area
 
Are you sure its not the front cover leaking where it attaches to the block? Did you use the restrictor for oil pressure into the pump?
 
I spent over 2 hrs looking one day you can watch it with a mirror and a light. We would clean it off with with break clean and then it would slowly run from where the pump meets the case. It runs down the corner of the pump then drips onto the power steering pump. Where is the oil sending unit?
 
I changed orings and it seems to not leak as much before when I was a the gas station getting fuel, I would leave it run, pump the fuel go in and pay and there be a stedy drip and a spot about the size of your fist, I changed the oring again to the thicker square cut oring and after getting fuel there was like 2 drops. So I'm thinking it's that oring or if maybe the case is warped or something. I'm about 99% sure it's not the tappet cover it looked really dry when I took the pump off. But I'll check what ever you guys say to, I'm out of Ideas.
 
I'm pretty sure that's not leaking but I'm gonna check again. I don't get it, I drove it all day yesterday and check this morning and there was just a few drips. I don't know why it would leak more sometimes then less other days. Does anyone think my crank case pressure may not be venting fast enough?
 
I had this issue on a pump I bought off Craigslist. It ended up being an industrial pump that had an open oil port on the front. It sits right up against the timing case. It can be sealed up with silicone.


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Mine would seep from between the pump and timing case. I kept thinking - how is oil coming past the o-ring when it's not pressurized. Finally called Seth and he told me about a hole that's not plugged if the pump is from an industrial application.


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diesel_importer said:
Finally called Seth and he told me about a hole that's not plugged if the pump is from an industrial application.


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therabbittree said:
8.3 pumps have oil port on front too


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^^^ This- if the pump came off an 8.3L engine it has an oil feed hole in the front of the housing just above the steel pilot that slides into the front cover. If it's a 5.9L pump, verify the mounting o-ring isn't cut or rolled and use oil/ grease on it when installing the pump
 
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