After a complete flush we used several coolant pellets on our 94 Deville with 4.9. It turned the fluid to an ugly brown muddy look. Is this normal? I know this has been covered before, but is there any engine damage that can occur if we chose not to use the pellets next time? I tried to search other threads but only found that most suggest using the pellets. We couldnt find any info suggesting that the lack of using them could cause serious problems like head gasket failure. There is no mention of using pellets in the factory service manual (at least no reference that I could find).