Archived Fuel in Oil....AGAIN!!

[AndrewKing]

Hi All,



My truck was recently sidelined when I discovered fuel in the oil (I was at a stop light and the oil light would flicker... Being paranoid I checked the oil level even tho I had just recently changed and refilled the oil... The truck does not leak or burn oil... Yet the oil level was way above full (3 or so inches above the full on the dipstick... A closer look at the oil and I noticed a diesel smell... not milky like a coolant leak... luckily the gauges worked as I would have had no other indication that there was a problem... I had the truck towed as soon as I noticed the oil light and the fuel in the oil).



At the recommendation of the mechanic, I had the injectors replaced with new factory units... The mechanic said the old ones were all carboned up and he theorized the carbon may have held the ball(?) open on the injector causing it to leak into the engine... . I suppose this sounds reasonable... .



Anyways, I got the truck back (he changed the oil and filter too) and the smoke at idle was gone and the truck ran smoother so I guess the new injectors helped big time BUT I noticed that the oil pressure guage was reading lower than 1/2 way where it normally sat (this was after driving it a total of 35 or so miles... . Matter of fact the oil gauge at idle would sometimes only be a 1/4 above the low reading... This worried me a little so I theorized that maybe some of the residual diesel in the oil was thinning the new oil...

I decided to change the oil again... . Much to my horror, the oil cam out so fast and in such a quantity that it overflowed my catch pan (normally on my other Cummins Trucks it works fine so I knew something was up)... Diesel small in the oil again!



I seem to recall that there was the possibility of the injector pump front seal leaking but another member here also mentioned that it could be some sort of pump that could be leaking too?... . What pump is this?... . I figure it may be easier to replace this pump than trying to fix the injector front seal which would probably involve removing the injector pump from the engine... .



Anyways, thanks in advance for any and all help again.



Andrew

 

[TBurow]

either the lift pump or the front seal on the i/p is leaking, both will put fuel in the oil, the front seal is not too bad to replace, and gives a great oppertunity to do a gov spring and other mods.

 

[Joe Mc]

I seem to recall that there was the possibility of the injector pump front seal leaking but another member here also mentioned that it could be some sort of pump that could be leaking too?... . What pump is this?... . I figure it may be easier to replace this pump than trying to fix the injector front seal which would probably involve removing the injector pump from the engine... .



Anyways, thanks in advance for any and all help again.



Andrew

Andrew - Sorry to hear of problem - good that you caught it in time - my bet is that you have a bad seal in the front of the injection pump (P7100), fuel leaks into the front gear cover and drains right into the pan.



"Or", the mechanical lift pump on the left (driver) side of the engine, just above the starter could have an internal leak and dumping into the oil way. To me these two areas seem to be the only logical place a quantity as you describe, in such a short time, could be delivered to the sump.



I'd hope it was the "lift" or "transfer" pump that's your problem as I'm willing to bet it is way less $$$ than a P pump. Just my best estimate as I'm an overvalved unit.



Good luck and keep us posted. This site is not only good for helping us out in a problem but, also a great learning tool for those of us (like me) that have only owned specific versions of the CTD/Dodge Ram.



Joe Mc

 

[AndrewKing]

Thanks for the replies guys... Lift pump is what I am hoping it is... . I'll try ordering one tomorrow... . I wonder if Advance Auto has one or if I have to track down a cummins dealer... Just curious but when I replace the lift pump can I look inside the old one and know for sure if it was the cause or will I simply just have to drive and keep an eye on the oil pressure guage?

Thanks again.

Andrew

 

[TBurow]

put the suction line in a container of fuel, clamp the pump in a vise and plug the pump outlet. now work the lever up and down(the one the cam moves not the primer) and see if fuel squirts out of the hole where the pump bolts to the block. it may take some pumping but its the only way to know.



also it is a little messy, but couldnt you take off the oil filler tube and use a mirror to see if any fuel is rinning from behind the pump gear, or use a q tip in one of the bolt holes of the gear and smell it for fuel? worth a shot