92 Deville How to inspect the main bearings?
 

Hi, I started work on my car a couple of days ago to change my lifters and replace my intake manifold gasket. I found out that there had been a substantial coolant leak inside the front valve cover and a moderate leak inside the rear cover. Subsequently i need to replace all my rocker arms and push-rods because of the wear.

Now, i am about to drop my oil pan to inspect my oil pump and while i'm down there i wanted to check the bearings because i am certain that coolant has gotten down in the crank case. So far i don't have any bottom-end noise which leads me to believe that there might still be some life left in them, but i want to know what procedure to use to find out whether i really need to replace them.

I used to run 10W40 while my lifters were tapping, now i am going back to using 10W30. I am not sure if the heavier motor oil may have had an impact on the bearings. i have heard that people use heavier motor oil if their bearings are on their way out, but mine have not given me any indication that they are going out.

the vehicle itself has about 169,000 miles and it had been maintained really well by its 1st owner, who had it for most of the car's life. I am currently the 4th owner. The coolant leak has been present ever since i bought it, and it maybe due to one of the previous owners not putting sealant tablets in the coolant when it was changed.

if anyone needs more specific information on the matter i would be happy to provide it.

Any help on the matter would be appreciated. Thanks!