Which oil cap for a '92 6.5L TD?

[atikovi]

Previous owner put in this screw on cap:

It obviously doesn't fit because the fill tube doesn't have threads for it:

It takes a twist on cap. What other GM models would take the same cap so I could look in the junk yard.

 

[GM Guy]

basically, I have found that our rigs from dads 92 thru the 96 have the twist lock cap that would fit in that neck. of course there is a big split, going all the way up to my 99, and it has the notched cap. not really threaded, but it has a l shaped notch and a little divit on the neck that follows the groove.

so basically I can guarantee a 92-96 6.5 will have the cap you need, and a 99 and 2000 wont, and I will let someone else chime in about the 97 and 98.

if that cap is truly threaded, I would say it is probably off a gasser.

just checked rock auto, and a standt or gates replacement oil fill cap is just over a dollar, ac delco cap is 9 and change.

 

[JMJNet]

It should have 2 notches underneath to fit those 2 notches on the filler.

 

[atikovi]

Thanks. Checked at acdelco.com and it takes cap FC181 and lists over 6000 applications it fits from the 60's to the 90's.

 

[WarWagon]

The 92's have a pressure relief disc in them. You can use anything from the 1982 6.2/6.5 on up to what GM Guy suggests. The 6.2's allow air in with that tall oil fill cap and may spike the silicon in your oil samples. I would not use a oil fill cap that does not have the pressure relief as a high blowby engine will leak more oil that way...