How warm is too warm for my engine? I've replaced all the cooling components, ( rad, thermostat, water pump, rad cap, all hoses and of course the coolant). Its gotten warmer, ( the weather ), nothing extreme and now if I use the AC the temp needle goes past the 100 mark almost hitting the next line. It'll hit the 100 mark even without the AC on in just a bit of traffic. Also the other day I was driving home and even on the highway doing 55, ( about 95 kmh ) the needle would not go down even when I turned the heat on. What could be the problem??? Last summer I had no problems and I had all the original cooling system. I'm at a bit of a loss so any help would be appreciated. Thanks.
P.S. I'm pretty sure I've gotten all the air out of the system I even drilled a couple of holes in the thermostat like I saw somewhere here.

 

if it runs around 180 to 210 degrees farehneight i woundnt even worry about it. my jeep will run about 5 minutes and heat up to 200, but thats because its got a cracked exhaust manifold. and if its only hitting 100 degrees farehneight that is way too cold. a great operating temperature is 180 to 210.

 

Proper runing temp is 195 degrees what thermostat should open at. I recenlty have been havin over heating problems myself. Have you tried flushing your cooling system cause once you get a high mileage engine hot your bound to kick up sediment like rust or dirt. Look inside your overflow tank see if it has anything sloshin around in it & when you pop radiator cap off do you see clean fluid or slightly discolored fluid? You shouldn't have drilled holes in thermostat if you want heat in winter time also will make it harder to run at the right temp should run colder. If your worried about air & you do need to flush cooling system cut a flushin t in the upper radiator hose the 11/16".

 

Fellas, I think hes on the metric system where a 100 is 212 Fahrenheit. With that said 212 is fine. I just changed everything to an open system and I was running hotter than before. I ended up buying an IR thermometer that claimed I was fine, I tested the gauge sending unit (which was new) and it was 190 ohms (normal operating temp) I tested the gauge couldn't find anything wrong, bought an after market gauge and it reads normal. I beleive my factory gauge had good wiring but was messing up. If I would unplug the gauge when it was claiming hot, then plug it back it would go right to 210, then over the course of 30 seconds creep up to red.

 

Thanks for all the input guys! I'm just curious though, my gauge reads 40-100-125 for the degrees. Like I mentioned it'll run past the 100 mark almost to the next line. Last summer with all the original stuff it never did that. At what degree does damage occur. Oh yea, I put in a 195 thermostat. Thanks again.