Coolant temperature going higher that it should be

It's the first time I've driven my car in summer heat (90+F) since I've owned the car for 4 years and never noticed this before.


As I was driving on the freeway temperature was around 94F and I got my AC on, I noticed that my oil temp was going down but my coolant temp started to rise up. It went to the 3/4 mark of the gauge and I turned off the AC to be sure it did not overheat.

Was wondering what could the cause be, I already did the cooling system overhaul (pump, thermostat, radiator, and expansion tank along w/ new hoses). The pump is actually under 3,000 miles and the radiator is a performance radiator that is beefier and performs better than stock (CSF Radiator), hoses are Minamoto's. Only thing I can't remember is the thermostat, I've bought it from amazon and that's all I can remember about it.

I've switched my clutch fan to a SPAL fan but I have went and driven the car w/ clutch fan delete for a while but then again it wasn't summer so I never needed the AC at that time.

Also change the auxiliary fan recently.



I've seen people who has the same set-up as mine, and some even has clutch or aux fan deletes and never had problem on highway speeds but they do see temps rise up on idle which makes sense since there's 1 less fan doing the job, but in freeway speeds my problem don't make sense to me.


And at red light I can see my temp go up a little bit, but the moment I rev my engine at 1.5k and above it goes back down to the middle which again I find weird.


The only thing I can think of is the thermostat is either not opening fully or its sticking or having a hard time opening even at temperature.

Anyways any idea's what to check that'll be great. Thank you.