I recently get a 97 blazer 4.3l with the thermostat removed.Any problem that i should be aware of? Any help will be apreciated, thanks!

 

Previous owner may have had overheating problems.
Blocked rad or heater matrix.
Or It could have an ongoing problem with a leaking rad / matrix or pipe, and the previous owner put rad seal in there. I hope its not the block or head.
Try it with a new thermo in and let us know how it goes.