[Ranger]

Remember, people come here when they have problem, not to say they have none, so your view is a bit skewed. That is not to say that the Northstar will never have a head gasket problem but there are many on here with over 200K, a few with over 300 and one with over 400. That said, the 4.9 is a very reliable engine. Which ever way you go, be sure the cooling system was maintained properly. Regular coolant changes (2yrs/green and 5/yrs Dex) is the single most important factor in head gasket life or lack thereof.

 

[Ranger]

Excellent point. This board is a poor sample for a reliable statistical analysis.

If one were examining a used Deville with a Northstar, what is the easiest way to check for "gasket" problems?

Head gasket problems will manifest themselves as an overheating situation and/or coolant loss. There are test kits that supposedly test coolant for exhaust gasses. That would be the "easiest" way. The most fool proof is the cylinder pressurization test. Pressurize each cylinder with shop air one at a time. Listen for an air leak (hiss) at the tail pipe and look for bubbles in the coolant surge tank or overflow bottle, depending on the system.