Heavy Equipment Forums Heavy Equipment Community

Cat parts oddities.

Mobiltech ยท 2022-11-14 18:58

Sometimes I run into Cat part numbers that make me wonder ***. On a c15 or 3406E injector sleeve some use a 1662903 seal in the top groove 1662904 seal in second groove 9x7430 seal in bottom groove While others use a1662904 in both upper grooves. To me the 1662904 looks like a coolant only seal so why is it used against fuel? Maybe I'm overthinking it.

Replies11
  1. #1Kelsey L.S2022-11-16 00:54

    1662904 is an o ring seal, so it can be used in many places.

  2. #2Chrisso2022-11-16 07:33

    It's to do with the the injector sleeves updating from 104-5536 to 166-3739. - Old sleeve gets a 166-3718 in the top and middle. - New sleeve gets a 166-2903 in the top, 166-2904 in the middle, - 9X-7430 in the bottom doesn't change. SEBD6726 tells the full story but that's basically it.

  3. #3kshansen2022-11-16 07:46

    Is there a way to view Service bulletins/letters through SIS? I'm assuming they are not available with the limited access I have these days. Up until a year or so back I could view service manuals with spec's but these days about all I can view are parts manuals

  4. #4Mobiltech2022-11-16 09:53

    Ok I did find that letter in truck news. My problem is the fact that when you go to order seals it says there are 12 of the 1662904 and no 1662903 until you go to a different serial number. I think its a mistake on sis.

  5. #5Mobiltech2022-11-16 10:02

    Is it fuel and oil resistant? Thats the question I have. The first ring seals fuel. The second is in coolant. I think thats why they have a 1662904 and 1662903. 2903 on the right 2904 on left.

  6. #6Nige2022-11-16 11:19

    I wonder was the sleeve/seal update referred to in SEBD6737 as a result of the issues with early versions of the C-Series to end up with fuel in the radiator.? There is also another Truck Engine News SEBD6706 that has illustrations to go along with the text describing the change of injector sleeves and seals. 166-2904 must be resistant to fuel/oil to a certain degree because the specification is to lightly lubricate the bore with engine oil before installing the injector sleeve.

  7. #7heymccall2022-11-16 11:23
  8. #8Mobiltech2022-11-17 09:11

    Thanks. Thats what I wanted to see. I will order the 1662903 for top groove and 1662904 for second groove and disregard the confusion on sis.

  9. #9Nige2022-11-18 12:56

    It's unfortunate that with the introduction of SIS2.0 the ability to make Feedback on errors encountered in SIS is limited to dealer personnel only. I think that's a backward step, it used to be that customers could also give feedback.

  10. #10mitch5042022-11-18 23:22

    It was probably put in by the builders of SIS because they wanted to receive less error reports.

  11. #11Nige2022-11-19 03:40

    Those who care just get their dealer mates to do it for them ......