Like I said, it's been about six months but my recollection now is that I couldn't remove the lower engine block plug. I removed the bleeder bolt on the top of the engine block (to remove air bubbles) and fluid started flowing out so I immediately screwed the bolt back in and filled the radiator with fluid through the top of the radiator. Reviewing the Haynes Repair Manual instructions I was following, it says to run the engine with the cap off until upper hose is warm and then add more fluid, if necessary. The instructions don't say anything about filling the block through the upper radiator hose. So, does it sound like I inadvertently let some air in somehow? Should I remove the upper radiator hose and fill it with antifreeze? If I could catch a $39.99 sale on flushing the radiator I'd go for it but without a sale I think the rate is $70-100 - a little steep if the solution is simply adding fluid to the upper radiator hose. Thanks again. You guys are the best!