Thanks Tom,

I really do not (or at least hope not) there is a problem, because I have heard that 90*C is not uncommon and it normally stays around 80*C, but it is the wide fluctuation I was wondering about. I will try a new cap. Should I go to the dealer for a new cap, or will one from an auto parts store be sufficient?

About the oil - we have talked about this in detail in the past. My car does peg at idle when cold and when fully warm (80*C), it idles at about "1", when it is slightly below 80*C, it is about "1.5". When fully warm and in gear, (500 RPM) it is around ".3". In the owners manual, it says this is correct, but there were times when it was around 90*C that when I would come to a stop, it would drop to ".1", then back to ".3" which I do not like. My car does have 264K miles and it is 21 years old, so I do not expect the engine to be up to new standards.

Perhaps it is normal, but I am not used to these cars yet and a bit paranoid I suppose. I used 15W-40 oil last time and was wondering if any other weight of oil would increase it. Guess not.

Thanks!