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Jeff753 · 08-24-2020, 02:15 PM

Anyone know the part number of a oil filler cap for a 2001 cummins 350 ISC 8.3? Forgot to put it back on (pound head)

8.3Oilbuner · 08-24-2020, 02:33 PM

Hi Jeff; Went out to the coach just now as I bought an extra as the ratchet mechanism in my cap is starting to fail. I think I got it at an Advanced Auto parts store here in Wa. State. It is a Master Pro Select, part number-8111. Looks the same as what is on the ISC now. Hope this info helps. This is for my 01 ISC in my Windsor!

Jeff753 · 08-24-2020, 05:09 PM

Quote:

Originally Posted by 8.3Oilbuner

Hi Jeff; Went out to the coach just now as I bought an extra as the ratchet mechanism in my cap is starting to fail. I think I got it at an Advanced Auto parts store here in Wa. State. It is a Master Pro Select, part number-8111. Looks the same as what is on the ISC now. Hope this info helps. This is for my 01 ISC in my Windsor!

Awesome. Thanks. Wouldn’t you know I left it off, drove two days and pulled onto my new (2 month old) pad for the second time ever.

Now to get oil out off concrete

Thanks so much for the part number. Does it have a rubber seal?

jacwjames · 08-24-2020, 05:53 PM

Don't feel bad, I did the same thing. There was oil everywhere. Spent a day cleaning it up and believe it or not I found the oil cap laying on top of the compressor. Check, you might get lucky too.

8.3Oilbuner · 08-24-2020, 08:57 PM

Hi again Jeff; Yes, has the big O ring under the top of the cap just like the original.

Jeff753 · 08-25-2020, 06:41 AM

Now I’m confused for my 2001 350hp 8.3 Cummins —
My old lost cap was like the 3945254 (first picture) and had the ratchet.

Cummins said it should be the 3901895 (second picture) which seems to be hard to find

Does one let air in or are they both functionally the same?

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8.3Oilbuner · 08-25-2020, 02:11 PM

Hi again Jeff; The oil filler cap on my 01 Windsor with the ISC engine has the first cap picture you posted. That is that same as the replacement info I sent you yesterday. My previous 2000 Windsor with an ISC had the same oil fill cap with the ratchet mechanism in the cap. Not seen the second cap on an ISC, but have not looked at tons of them to be sure! As far as I know there is no vent in the cap and I would think both would work the same.

Alpine36 · 08-25-2020, 02:25 PM

The second cap pictured looks like the fill cap that goes on the timing cover, not the valve cover.

Cdr151 · 08-25-2020, 07:50 PM

Yes second cap is the one on timing cover lost mine last weekend ordered one if it is right I will let you know. If you down load the Cummins app you can lock up part numbers

Jeff753 · 08-25-2020, 08:30 PM

Quote:

Originally Posted by jacwjames

Don't feel bad, I did the same thing. There was oil everywhere. Spent a day cleaning it up and believe it or not I found the oil cap laying on top of the compressor. Check, you might get lucky too.

What are the odds? Found it laying behind the compressor. Good tip.

As mentioned the 3901895 is the one on the front lower

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cover. 3973511 is the one for the valve cover.

Cdr151 · 08-26-2020, 07:06 AM

Correct number for timing oil cap.

jacwjames · 08-26-2020, 08:21 AM

Quote:

Originally Posted by Jeff753

What are the odds? Found it laying behind the compressor. Good tip.

There you go,

Took me a good day to clean all the oil up, we were then parked in Valdez AK, happened between Tok and there. When I opened the back compartment and saw all the oil I panicked, I thought for sure that then engine would go bad loosing that much oil from appearance, but it was only a couple quarts low. Still a mess to clean up.