I've had a few people tell me GM doesn't recommend the use of Coolant Seal Tabs anymore, but I can't find a GM Tech Bulletin saying this. I did find this from March 2004 (read 2/3 way down):
I'm not sure what to make of this. In one sentence they say:
"GM no longer endorses universal use of seal tabs. Procedures in SI have been specifically written to discourage their use in most cases."
Then they go on to say:
"If seal tabs were installed in a vehicle at the factory, itís OK that the proper amount of tabs be installed if the coolant must be drained and replaced."
So I just replaced my coolant....do I add the Seal Tabs or not? My Service Manual says add 6 pellets, part #3634621, which is the same # in this GM Tech Link.
So what's the concensus? Anybody replace their coolant and not use the Seal Tabs? Were there any negative effects...like coolant seeping or leaks?