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If you do a pressure check, would bad coolant / radiator hoses cause the test to fail?
I have had 2 mechanics trying to figure out why I am losing cooling fluid. Pressure test didn't turn out any problems. One of the mechanics told me, that the cooling hoses are kind of stiff. But wouldn't bad hoses cause a pressure test to fail? Also would a pressure test be able to identify a blown head gasket? My assumption is that it should?
A pipe can have a really small hole which only starts leaking when the system is fully hot and therefore at full pressure - it then can release cookant which effectively instantly vapourises and leaves very little trace - except for the scald on your forearm as you get close to it... and that is how I found it - pain is a good educator...
So, be careful - leaks can be difficult to trace...
A short term pressure test may not show a small leak. Doing the pressure test overnight may show signs of small leaks, but can still be difficult to find, (the pressure dropped but can't find a leak). A blown head gasket may show up if the sparkplugs are removed and the system is pressurized. The coolant may collect in the cylinder bore. By turning the engine over slowly by hand you may see the coolant expelled by the piston.
