It could be the head gasket, as a blown head gasket between cylinders can lead to that kind of starting sound. It would have to be really bad for the car not to start, though.

The timing belt could be the real problem. The coolant could be brown because of system contamination, corrosion, or a number of reasons. Oil in the coolant will usually appear on the surface, though. At least partially.

When you verify the t-belt, you have to have access to see all three of the alignment marks; cam, crank, and intermediate shaft.

Obviously a compression check would be in order if you find the timing belt to be lined up properly.
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chris herbst, near chicago