Toyota Repair: Water in Oil, timing chain cover, head gasket

Question
My Dad has a 1990 Toyota pick-up 4x4, 22RE engine. He has water in the oil. He has had the head gasket changed but this still did not work. There are no visible signs on the gasket to indicate it was coming from the head. He said he checked the antifreeze before last winter and did not think that freezing could be the problem. I know growing up he was very strict about this. I looked and did not see any bulging freeze plugs. Is there something other than a cracked block that could cause water in the oil?

Answer
Yes there  a couple of other ways this can happen, the cylinder head may have a crack in it, when the head was off was it checked for cracks? Another possible cause may be that there is a leak inside the timing cover,I have seen this happen many times, if the timing chain is worn enough it will make contact with the inside of the timing cover and rub through into the water jacket, the cylinder head possibility can be eliminated by doing a simple combustion leak test, this can be done at the toyota dealer or an independent shop that has the tool to do this, it's a chemical test for hydrocarbons in the cooling system, if the test is negative then the coolant is coming in elsewhere, probably from the timing chain cover.