I've owned 16 Cadillacs over the years - 1939 up to my 2008 DTS. My favorite engines were the 472 (which is in my currently owned '70 limo) and the 500 that was in my '75 Sedan DeVille. Actually, there were no "bad" engines until the 4.1 debuted. I tell anybody who asks about buying a used Caddy to avoid the 4.1, 4.5 and even the 4.9 motors. There were very few 4.1s that went 50K miles without head gasket issues. A few more 4.5s made it to 100K. Probably half of the 4.9s will make it to 100K. In normal Cadillac terms, these are TERRIBLE percentages. I would also avoid the first year Northstar engines - they developed valve guide wear around 50K. The newer Northstar engines are great, but a little difficult to work on - a lot of non-dealership mechanics can't even find the starter. The old 365 and 390 motors are very durable.
Bob Woodside
