What are some signs to look for on checking your rod and connection bearings. I've pulled them down heard noise in the motor ended up possibly being my flex plate bolts making a bunch of noise. heard a squeaking coming from the motor not sure if it was the torque or a bearing going bad in the motor. I opened it up and have pulled the caps for the main bearings and also the connecting rod bearings. to me they look good some small lines in them but nothing that signals they are going bad. no metal shavings in the pan when i took it off the motor. oil was milky colored

 

Milky oil is a sign of water in oil. Plastic gage the bearings to see the oil clearance. Is the crank journals scored or burnt?
These 4.3s can be noisy. Counter shafts & bearong & also the gear are TBSs on Blazers, Sorry I missed what year your working on.

 

Sorry about that I thought I put it in there this is a sbc 350

scored or burnt..i'm figuring this would jump out at you pretty good if it was this. would it show up on the bearings or on the crank? I'm going towards the side of not guessing or assuming. i'm sure the way I'm thinking is correct. i've done most all my own work. first time getting to the internals of a motor. so im erroring on the side of caution.

 

Wow 1st time I read it I assumed it was a 4.3 because of your sig lol.
Personally only connecting rod bearings are all I've replaced. The things I/we looked for were of course scoring, scratches but also took a digital micrometer & measured width & thickness in 3 places. Each in the same area - both ends & in the middle & compared the results to other bearings & their position (top or bottom). Mine were narrow mostly & that caused a clanking sound in the bottom end but could be heard easily through the valve covers, so it was confusing. All were lightly scored & thinner in places & it didn't seem like that would be an issue because the difference was so little.
It does NOT take much for them to cause noise if they're worn & having milky oil = they have been abused. FYI mine were gas washed so that meant oil wasn't able to be the protective film/barrier it's meant to be. Antifreeze in the oil will have similar effects IMO.

FYI Clevite 77's were only around $70 for my 4.3 & a bottle of Lucas assembly lube was $10. All in all a cheap fix if you don't consider the time factor by DIY.

 

i was told it had a fresh rebuild which i'm thinking is true. I think the milky oil came when i did the new rad install and it overheated on me. from an air pocket in the coolant system