The cheapest rock auto part with a heart next to it has never let me down!

I wouldn’t send it. Order from rockauto with the fastest shipping they have. And find a ride to work, or call in sick, or ride a bike. Usually there’s a 2 day shipping option. So the struggle should only be on Monday.

Sounds like your thoughts make sense. Fill it up with water. Turn the car on to idle, And run some head gasket failure tests. Check the tailpipe for white smoke. Look for external leaks when’s it’s idling. See if the coolant is actively going down, or bubbling in the overflow tank from exhaust pressure. If the overheat caused the head gasket to blow. Your only option other than a rebuild or new engine, is to try a head gasket sealer, and do an oil change as well to get the coolant out of the oil… And see if it stops the leak.

Buy a brass barb fitting of the proper size from the hardware store for $5. You don’t even need to tap it, just drill out the hole about 1/32 smaller than the size of the brass fitting. Then screw the fitting, threading it into the plastic. Put some JB weld maritime putty around the end. Idk what size you need but link below is the kinda thing you’re looking for.

https://www.amazon.com/Anderson-Metals-57001-0404-Fitting-Adapter/dp/B002SAO7XQ/ref=asc_df_B002SAO7XQ&mcid=b69668fccd64340dab85d40192819373?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80539344142694&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=m&hvlocint=&hvlocphy=&hvtargid=pla-4584138871873597&psc=1

From a DIY perspective. Save up $500 and buy a beater old car (and do yourself a favor make it a relatively common American or Asian car). One that’s pretty crappy but still runs is ideal. Then buy the Haynes repair manual for that car, and start YouTubing repairs. Donut media and chrisfix are good YouTube channels to start with.

Double check everything then start her up. Don’t be alarmed if it smokes a bunch out of the engine block upon the first start.

Head gasket sealer only “works“ due to The heat from the combustion chamber solidifying the product. So I wouldn’t count on it for external leaks. Do your valve cover first, that’s more likely to be leaking, and a lot cheaper to fix. If that doesn’t solve it then worry about head gasket.

“I’d love to help but I don’t have time to do that”. Or “hey since you like carpentry how about you come over and help me rebuild my deck next weekend, and I’ll swap your brakes out while you’re hear”