1983 cat 953 getting fuel in the oil

1. #1pittsburgh cat man2025-09-30 14:39

   I’m guessing it like a 20z there’s o rings on tubes running through valve cover might be a good idea to pull valve cover and look for clean spots that may help

2. #2Nige2025-09-30 15:29

   A machine Serial Number is always a good start. That's what all technical information is based on.

3. #31990cat9532025-09-30 15:53

   i know it starts with 05z

4. #41990cat9532025-09-30 20:07

   serial number 05z00428

5. #5Nige2025-10-01 04:40

   From about the same time frame (81-85) as an early 20Z machine. Attached the part for the fuel injection lines as mentioned above.

6. #61990cat9532025-10-01 18:02

   would it more than likely be o rings from page 5 part 10 and 11 for crossover tube?

7. #7pittsburgh cat man2025-10-01 18:16

   It's possible but there is a passage in rocker cover that is suppose to drain leakage out the back towards the hystat

8. #81990cat9532025-10-01 20:50

   well took off the valve cover and idled the machine didn't see fuel spraying out of anything obvious none of the fittings could the injectors be causing it. hoping I would see something obvious but haven't so far

9. #9pittsburgh cat man2025-10-01 20:57

   I was thinking of a possibility It could be leaking thru plunger on transfer pump

10. #101990cat9532025-10-01 22:09

    where is it located ?

11. #11pittsburgh cat man2025-10-01 22:28

    On the injection pump

12. #121990cat9532025-10-02 19:00

    well took off fuel transfer pump from injection pump hooked it to the feed line primed it up really hard with primer and operated plunger am not seeing no fuel seeping internally . so. that's not it .. I've been noticing the back side of my injection pump has been a little wet I guess it could be possible theres fuel mixing with oil inside injection pump itself? next thing i was gonna try was take pump gear cover off from the engine and look if it possibly could be leaking from the front of the pump to the gear case if that has a seal that could leak that direction . thanks for any advice

13. #13pittsburgh cat man2025-10-02 19:42

    Some questions 1 how much fuel did they say was in oil 2 how many hours on oil 3 any smoke and what color?

14. #141990cat9532025-10-02 20:23

    that's the thing machine runs clean when running . oil sample said oil viscosity was like 3/15 when it should be 15w40. I changed oil the other day and probably ran it 5 hrs and am 3/4 inch over full on my dip stick so alot of fuel is coming in .

15. #151990cat9532025-10-04 11:50

    found it! top of one of the injectors. should I just replace the one or replace all four?

16. #161990cat9532025-10-04 12:02

    any brand recommendations? also do they require a special puller or can I just get a couple pry bars and pop them out ? thanks

17. #17pittsburgh cat man2025-10-04 12:16

    No puller needed remove line from injection pump to the part that goes through valve cover remove injection line at the part that goes thru valve cover remove hold down bolt and clamp if I remember it’s 5/16 12 point grab injector by line and twist while pulling up on it usually doesn’t take much to get them out

18. #18pittsburgh cat man2025-10-04 12:29

    If there is a lot of hours on them I’d do all of them

19. #191990cat9532025-10-04 13:00

    ok yeah he meter says 11000 but hasn't worked since I had it do u recommend any certain injector ? thanks

20. #20pittsburgh cat man2025-10-04 13:05

    I think I would check on cat or’s first

21. #211990cat9532025-10-11 22:54

    got injector changed. and changed the oil. machine is good to go again ran it for about 5 hrs today not making oil anymore! working on clearing 12 acres cleared about 8 so far . thanks guys for the help

22. #22ccc enterprises2025-10-21 16:15

    COuld be from injector orings or orings in fuel pump in govenor, oring where the pump seats in the govenie