Loud squealing after oil change 89 K5 Blazer
 

I just changed my oil and when I started it there was a very loud squealing sound I have never heard before. I took off the oil filter, took off the drain plug, and let everything drain. I bought a new oil filter, put it on, put the plug in, and put oil in the engine. Started it up and then there was a loud squealing sound that didn’t go away. I didn’t wait very long to see if it would go away. I have changed the oil in this truck dozens of times and have never come across this sound. I can’t seem to find anything online googling the problem. Anyone run into this problem? Of course this sound was never there before the oil change.

Figured it out
 

complete coisidence, but the belt tensioner gave out/seized up after I changed the oil. The belt was sliding across it squealing.