All of my mods are in my sig. Just put it back together last night and was running through the heat cycles fine then all the sudden it starts steaming and spuing coolant out the over flow hose. It did this to me about a two weeks ago and lost all compresion so i tore it down and found a ring embedded in the head and blown head gasket so i sent the cylinders off to HJR (awsome job) and before i put back together took off the water pump cover to check and make sure it was functioning right and it was but when i looked at the back of the water pump cover you could see where the impeller had been rubbing it alot but put it back on. Checked all of my coolant hoses and they were fine. My radiator has no corrotion or build up in it. Bought a billet impeller, gear, washer, circlip that will be here on thursday but would like to know what else i need to check. Not sure why its doing this but any help or advise would be helpful and appreciated.