You could pull the valve cover, turn the engine until both rockers of the cylinder being tested are on the base circle of the camshaft. Put air in the cylinder either through an injector hole or glow plug hole and listen for the leak. You have to make an adapter to do this.

This isn't as perfect as a leakdown test with gauges because the piston is at the top and you don't have gauges; but, we already know the leaks are bigger than acceptable. This is the same thing leakdown readings would tell us. At this point we want to know the location of the leak.

Christina, Is there any feasible way to get a borescope into the cylinders? Looking inside may tell something such as scoring or corrosion. Phone endoscopes are around $25-30.

Good luck!!!

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