Those who know about a 1967 Case 830 inside please

I have a 67 Case 830 CK (has gas engine so I'm told it is actually an 840?).

Anyway I have two questions. First, when I shut the tractor off after using it for a longer period of time (at least 30 minutes) it will run on a little bit and then blow air out the intake. The glass bowl (on the intake tube at front of tractor) has been getting dirty so I decided to remove it and clean it and when I look down the tube I see liquid in the bottom. It appears to be water but unsure how it got there. I have no leaks in the coolant system and don't see how coolant could get there anyway. I assume this is not normal so how can I drain this without taking apart the entire front?

Second question. I need a new radiator cap as mine is getting old and worn out and I either need to know where to find a correct replacement or can someone tell me what pressure the cap is so I can go that route to finding a replacement?

I have a manual in PDF format for the tractor but it is about 600 pages (includes diesel and LP as well as the gas) so I skimmed and seen nothing relating to either of my needs and google was a waste of time.

Hope someone can point me in the right direction here.

My son had an 830 gas that backfired a bit when he shut it off sometimes. It would blow oil up from the air cleaner making a mess. The 830 has an oil bath air cleaner and what you see down the pipe should be oil and not water. You can easily get to the air cleaner by taking off the front screens. I have an 830 diesel which does not have any blowback from the air cleaner.

I forgot to mention you can get a radiator cap and most any other parts you need from places like Steiner Tractor or Elmer's Repair from Centralia, KS. Elmer's has new parts and wide variety of used parts for the 30 series Case tractors. I live in IL and drove to KS to get parts when I was restoring my 830. He can ship most anything but I was getting weights and wheels.

Always let an engine idle a few minutes after
working it hard. This will let the valves and engine
cool down before shutting it off.This should take
care of the dieseling( running on) and the
backfiring.

Never even thought about it being an oil bath filter system. Just thought the can up front housed a filter but I got it apart after some off bends since the previous owner put bolts on the left screen instead of the quick screw things and cleaned it up and it looks much better.

Thanks for the quick responses everyone.