New member, have a question

[edgar702]

Hi guys, first let me introduce my self, im Edgar live in Vegas and just bought a 99 Q45t.

The car has 148k its in great shape but on my drive back from CA to Vegas the water temp went up like half inch and after 20 min it went back down did not over heat, today it was 105 outside i drove like 2 hours and it did the same thing, the temp will rise and after a while it will go back down.
I have a feeling that when it starts to rise and if i drive it harder it might over heat,

anyway I will change the Thermostat and see what happens, did anyone have this issue or has an idea of what it could be, fan is working coolant is normal,

I appreciate your input

[Q45tech]

You cannot trust the inside temperature gauge because it is designed to be non linear.
11 year 148k is time for cooling system rebuild overhaul especially radiator. Just a few percent each year in annual degradation finally adds up to less than brand new cooling.

All cars [prototypes] are tested before first sale in Arizona to survive 120F idling in a nearly closed box [zero wind].........it's downhill from then.

Thermostats are designed to be fully open by 196-200F any rise above that means the rest of system is not up to par!

Too much AF in coolant mixture decreases transfer efficiency. Tap water added over years contains calcifying dissolved solids which coat inside of aluminum, acting as an insulator.

[edgar702]

Thanks, so other than getting a new radiator and coolant flush, what els should i change