Injector cups

[Rawze]

the way to find out is to pressurize the whole coolant system to 20-psi ( 5 psi over its rating) with the oil pan and stiffening plate off it, and let it sit over night.

Then have someone bar the engine over slowly with a big wrench the next day and listen for gurgling sounds (instead of a dry hiss) on the compression stroke for each cylinder. See if any droplets of coolant (or anything else like fuel etc.) are seeping out around the rings if it does gurgle.


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- if you get a cylinder that seeps coolant then pull a suction on the coolant system using a vacuum pump after draining a gallon or 2 so from it .. pull that injector out for the seeping cylinder ... and then pressurize the coolant system again with the injector out, but this time, to only 5 PSI max. See if the cup is leaking into the cylinder with 5 psi on the coolant system. If not then its the head gasket.

NOTE: 5-psi is the max allowed to pressure in the cooling system that is allowed with injector(s) removed from the head. Otherwise, you take a risk of actually causing an injector cup to blow out and leak, creating a problem.

NOTE: pulling a fairly strong vacuum on the coolant system is also recommended any time someone removes injectors, to prevent getting, or creating a leaky/loose injector cup if the head is old.