md lucky 13 -
is it possible to start the truck? I wondered if you could drain the oil/syrup, install fresh oil and filter? You may have to heat the oil pan with a small torch to get it to run out. Then, try to get it running enough to warm it up and do a pressure test on the coolant system. If it's a coolant leak, you'll have the answer if you can DUPLICATE the failure of the oil.
I know that there is an extreme possibility that all the bearings are already fried, but I'm not talking about returning it just yet to the customer. I just think it would be a step in the right direction to be able to make the oil gel up a second time. If you can replicate the problem, it will be much easier to diagnose. Also, is there an oil-safe dye that could be added to the coolant that would be a tell-tale sign if it showed up in the oil?
If the problem can be duplicated, then the problem is most likely with the engine, such as major coolant leak. If the problem cannot be dupliated, it would more likely be an issue of mistake/sabotage. Could someone have "topped off" the coolant by accidentally pouring some coolant into the oil filler neck by mistake? Silly things happen, you know.