sorry for such a basic question, but this has been bothering me. When I turn the oil filler cap, in the bay, as far as I can... it rattles and isn't sealed. is this the normal / correct positioning? it's not coming off that's for sure, but in every car I have had the cap is always a screw on one that is very tight on the engine. I'm worried the rattle and not sealed cap will cause oil to spill out of the top once the engine warms up. again sorry for such a basic question, but alas here i am asking it anyway.

No problem. 

The cap being loose as you describe means that the rubber seal ring is dried out and hard.  Needs to be replaced.  Massive quantities of oil won't come out, if everything else is normal.  But it will likely leak some oil mist, make a mess.

 

You can try with a few o rings from any hardware / car parts store.

Try a dealer

 

I think one of the following may have one, but I am not sure:  Fel pro head set HS 9392 PT-2 or conversion kit CS 9390

awesome thanks Dave seemed weird to be, but this is my first 88...haha heading to the hardware store tomorrow.

I just checked mine, but it's a 86 GL, EA81. My cap has a thick rubber gasket inside, and its definitely tight. Perhaps you're missing the gasket?

Yeah, missing is also an option.  Should be pretty similar, if not identical.

If it was mine, I'd probably just RTV a ring inside there, let it dry, and be good to go the next morning.

I've bought a new one before at Oreilly's for around 5  bucks 

If it was mine, I'd probably just RTV a ring inside there, let it dry, and be good to go the next morning.

 

nice! good idea actually I'll go that route.

Another fix is to cut a piece of heavy gasket material to fit into the filler cap, on top of the hard and crunchy rubber seal. 

 

A loose one may screw up the PCV system, as air will leak into the  filler neck, instead of being drawn from the right place, wherever that is.  

Just to update. been running with the same cap. I just bent the prongs on the cap a little and it snugged right up. O-ring was still in place and not crusty. 

now , bending the prongs is a good idea - thanks for sharing ! I just got my shipment from Rockauto via a 5 year sojourn in WA state. Had two US made oil filler caps in it. new seals

 

Meanwhile I stuffed more glue under the seal in the cap, painted it a sexy yellow to make it look more modern - driver only need check yellow things ....

+1 on the easy check. Always into making things easier.

Keep an eye on the cap with the re bent tabs.   I did that once, long while back.  Eventually,  one of the tabs broke off.

5 hours ago, DaveT said:

Keep an eye on the cap with the re bent tabs.   I did that once, long while back.  Eventually,  one of the tabs broke off.

Ah good to know. It was very easy to bend - I'm not surprised you had one snap on you. Fingers crossed this one says whole.

Yes, I remember that also.  Metal fatigue.  Some grades / alloys tolerate more bend cycles than others.

Maybe rub a little vaseline around the O-ring with a q-tip, to keep it from drying out and cracking.

ummm, here in the US the gasket can be purchased new from the dealer for $1.28 retail. Part number 803935010

52 minutes ago, impostor said:

ummm, here in the US the gasket can be purchased new from the dealer for $1.28 retail. Part number 803935010

hmm... didn't know the gasket was still available new, would have been useful on my 79 Wagon i just sold since it made this strange goo on the very top of the filler neck, guess water humidity and oil were mixing there slowly, but that wasn't the reason i sold it, it was the overwhelming rust.

Edited July 2, 20187 yr by Subasaurus

Another good thing about Fuji, still sell some obscure parts for thirty year old cars. $1.28 ! That's half what Rock want for the cap and seal already adhesed in !

 

Was thinking of a fill tube deletion altogether but would be painful for oil changes and top ups

There are quite a few parts still available for ea71s and 81s if you have the part number. I just replaced the shifter bushings in my 80 brat with new OE stuff.