88 firebird 305tbi. Runs at the first big line below 220 .datalog shows it at 180. It's about 90 degrees outside is it normal for it to rise to the next small line ?

 

Seems like math is not many people's strong suite, since everyone discusses "the marks" trather than the associated temps of the marks.

Guage reads 100 then 220. 220 - 100 = 120 ... so there's 120 degrees between the two numbers right? 1/2 of 120 is 60 - so the line exactly mid way between 100 and 220 is 160 degrees. The line between 160 mark and 220 is half of 60, or 30 - so in the end we have 100, 130, 160, 190, 220 .... 30 degrees at each mark.

Bottom line is, unless the car is boiling over, it's NOT overheating.

Normal operating specs for your car is 220 on temp guage (that's why it's in the center of the guage). So any reading below 220 is good (unless it's below 160, then it's too cold, which is next to impossible on these cars, and thus you have a bad guage or sender).

Make sense?