1991 Pontiac Sunbird 2.0 Hey thanks. What a great service you guys provide. There is one more question that I forgot to ask. I recently (over 1 month ago) had a gasket replaced for antifreeze was spraying out of a tube, etc, and it overheated and so on. I have begun to notice that I keep losing antifreeze in the overflow bottle. The line at "full/cold" keeps dropping very low. I assumed that maybe since the car is old that I would replace the whole overflow bottle. I did. Well it keeps getting very low and I have to add antifreeze/water once a week into the bottle. One thing I did notice is that the cap on the bottle keeps spinning (when you tighten). I had to use the old cap; for the new bottle did not come with one. Could the cap be the problem? Thanks again. Same car, Pontiac Sunbird 1991 2.0 engine I’m told. 81,000 miles.
We do not think the old cap is the problem. Adding coolant once a week would indicate a leak. Carefully check for a coolant leak on exterior of engine and radiator. If no leak is found, you may have an internal engine leak (a failed gasket or cracked head)