I have never had a diesel before was wanting some advice on things to check and look for when buying a 6.0L powerstroke

 

Have a dealer pull an oasis report to see what its had done for warranty work. If its had a number of head gaskets then the heads probably aren't flat and will need to be pulled and remachined to get them flat. Pull the dipstick and check for any coolant in the oil. Also check for oil in the coolant. Look at the degas bottle to make sure that its not broken since that can point to other bigger issues.

Make sure you drive it enough to get it up to operating temp. Drive it hard to see if you can spot any coolant puking. This one will be hard, but at operating temp drive at WOT and have someone with a scan tool, scan gauge, or edge insight see what the difference in temp is between the engine oil temp and engine coolant temp. You want around 6-7* delta T ideally. If you've got a high delta then you've got a plugged EGR cooler and most likely a plugged oil cooler.

The 6.0L is a good engine if you do your research before you buy and plan to fix the short comings of the engine. Once you've got the issues fixed the engine is extremely stout. Most people don't want to deal with figuring out whats wrong and trying to fix it correctly so they say the 6.0L is junk. I used to be one of those people, now I own a 6.0L.