cummins ntc 300 getting fuel in the oil

1. #1MrKomatsu2012-11-25 10:13

   injector sleeves are cracked......

2. #2mrkw772012-11-25 10:31

   i 2nd mrkomatsu

3. #3stumpjumper832012-11-25 12:12

   does it by chance have a fuel lift pump mounted on the block like a 3.9, 5.9, or 8.3 cummins? If its a lever style lift pump that is mechanically driven, I've seen the seal go bad between the motor and the fuel and polute the engine oil on several occasions.

4. #4charles walton2012-11-25 15:07

   Thanks Mrkomatsu,how would you go about checking them?

5. #5johndeere1232012-11-25 16:16

   If you pull the rocker cover off and run the engine, sometimes fuel will be pushed up into the cover.

6. #6charles walton2012-11-25 19:01

   would that indicate a bad injector or a cracked sleeve or what? I am just trying to learn how to do this stuff as you can tell,any advice is appreciated.

7. #7johndeere1232012-11-25 19:37

   When i saw fuel being pushed into the cover, it was a bad injector. Im not sure how you would go about checking for a cracked sleeve.

8. #8MrKomatsu2012-11-25 20:07

   there are two ways to check.......pull head and send off to get pressureized.... or drop oil pan, pull injectors and find inlet at head for fuel rail, then supply it with air and watch for fuel to drip from block......

9. #9charles walton2012-11-25 21:13

   Are the sleeves also called injector cups?

10. #10MrKomatsu2012-11-26 12:50

    yes they are...

11. #11miro2012-12-03 10:23

    To see if it is the injectors you can mix up some UV dye and run the pickup and return lines into the dye bucket and run the engine with the valve covers off and shine a UV light down to see which injector is leaking, while the engine is running. If it has stc disable it

12. #12charles walton2012-12-16 12:21

    Ok,I looked in a parts book and found the sleeves,they're part of the head assembly,I just put new injectors in the old ones were froze up some what,if I'm still makin' oil when I start back I guess it must be the sleeves,I'm keepin' my fingers crossed.

13. #13shopguy2012-12-16 12:33

    ,,,

14. #14powerjoke2012-12-16 15:01

    Check inj o rings, visually inspect inj cups (usually good enough) if good sleeves and orings have the injectors tested because bore pitting will cause this, and usually occurs after long rest periods check crossover tubes, then pressurize with air the system it just takes a couple pipe plugs and adapters, and if you strike out there send the heads to get pressure checked (usually only cost $20), As far as the pump leaking, not likely. Edit: sorry for the post I re read your last post but already had this one typed up lol Pj