I just put in a new water pump, coolant replacement, hoses, etc. (didn't touch tstat) I never noticed this symtom before.
Symptoms: First run in the morning, 50F outside, 70mph. Temp climbs from dead low to 200 mark then keeps climbing to about half way between 200 and next unmarked tick mark (about 12 o'clock on the gauge). It then hangs there for a minute and then within 15 seconds drops to the 200 mark. After that it climbs to about two needle widths above the 200 mark, hangs there, and then drops to 200.
Is this a sign of a bad tstat? I'm kind of new at this DIY auto repair.
If I do replace the tstat, I don't know if I want to go with the 180F. Can I get half way in between the 180F and 195F by drilling two 1/16" holes in the 195F stat?