I'm thinking of going to look at a used '87 suburban with a 6.2.
Are the heads on these things cast iron or aluminum? a few years ago I had a bad experience with the aluminum heads on a GM 6 cyl diesel.
Any specifics to look for when checking it out( I'm well versed in heavy diesels and european auto diesels).

Thanks------Robert

The 6.2 heads are iron and they are known to crack and or have head gasket leaks. I bought an 85 with 135K and I had leaking head gaskets replaced. Mine weren't cracked but I had them put the sleeves in while they had the heads off, which is what they do when they crack.

ABOUT 90% OF THE 6.2L HEADS OUT THERE ARE CRACKED BUT GM SAYS YOU NEED TO PRESSURE CHECK FOR LEAKS. I GUESS CRACKING WAS VERRY COMMON BUT MOST DONT LEAK?

correct