Thanks, CroCivic91 and the briggsdude
CroCivic91: Wish I could get the valve adjustment done in Croatia! Thanks for suggesting I get a radiator at a salvage yard and install it myself or give it to the person who buys my car. I can't install it myself, but this confirms that a handy mechanic could repair this at a lot lower price than I would have to pay. So my car might be of interest to someone who buys cars and fixes them up for resell.
thebriggsdude: I use 10W30 oil. I don't know whether the engine is ohc or ohv. Here is what I know: it is 12-valve, 2.2 liter, fuel injection.
I looked up ohc and ohv and found a great explanation, but I still don't know which my car is. http://en.wikipedia.org/wiki/Pushrod_engine
Thanks for telling me that marvel mystery oil really won't help on ticking engines.