Needs head gasket examined.
“For sale 1947 Jeep Willy. Bought it, it runs but after running it for awhile header gasket leaked. Have a new header gasket but never but on. It starts but would only run it for a short time. While transporting the windshield frame broke.”
https://charlestonwv.craigslist.org/cto/d/1947-jeep-willys/6361167913.html