Do have things like a compression tester, cylinder leakage tester, and doing a leak down test on the cooling system. Even a vacuum gauge and a real oil pressure gauge.
World has gone crazy with these self diagnosing systems, based on an assumption all the sensors are telling the truth. When in reality, with no secondary references, the only thing these diagnosing systems can detect is if a sensor is either completely opened or shorted, stupid. Can be way out of tolerance and telling all kinds of lies.
The fact of the matter is that the IC engine has not changed in basic operating principle in over a hundred years, so one had to know how to test it with good reliable external equipment.
How about being told with your brake pedal going clear to the floor in a brand new vehicle, you ain't got a problem, not getting any codes. Wish I was lying about this, dealing with complete idiots.
Head gasket for the 1/4 L is only about ten bucks, another 34 bucks for new bolts, torque to yield bolts adds to the throwaway parts list. Head can be inspected for cracks, another new problem that never existed before, and more lies, claim aluminum saves weight, what a couple of pounds in the head of a 1.4 L? More lies, real reason is aluminum is a heck of a lot cheaper to manufacture.
Did have a minor crack in one, a friend charged me five bucks to heliarc it. But you don't know until you look.
When dealing with problems like this, consider the entire vehicle as whether its even worth repairing.
Ha, about about going to a wrecking yard in 1957 and getting a complete Caddy engine for 85 bucks, you know the mileage is correct, still in the vehicle, but had to remove it yourself. Only 8K miles on it. More in the history books, can't even go into the yards, anymore, least in Wisconsin, liability laws.
Last time I was there, don't go there anymore, showed me an engine laying in a mud puddle, said it was good. You can trust me.
