i have a 170* stat and 176* hypertech fan switch,, on the highway the car will be at 170-180,, but in the street it runs at 200 and today on the highway(traffic) it hit 220,, why is it doing this? last year it never went above 170*, never. the switch is new and working, and i tested my thermo not too long ago and it opens,, any ideas???

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1988 GTA Trans Am 350tpi: 46k miles,3:27 BW rear, aftermarket t-tops
Hotchkis: subframe connectors & strut tower brace
Flowmaster: 3inch exhaust& dual chamber muffler
Accel: 8.8mm wires, cap&rotor, u-groove spark plugs
Edelbrock: 52mmTB, intake & runners
K&N: filtercharger
TPIS: 170* stat, afpr, mat relocation kit
March: performance crank and alternator pulleys
Hypertech: 176* fan switch
Other mods: ported plenum, gutted cat, tb coolant bypass, homemade cold air induction, flux capacitor, driver side floor mat removed

 

sometimes you get a bad thermostat, also check between the radiator and the condenser for obstructions, it sounds as if you are having restricted/redirected airflow problems. Have you removed any te air flow peices from in front of the radiator? These are intended to direct the air through the radiator while the vehicle is moving. I had a similar problem with my Z. Once I determined that there were peices missing(by referring to the service manual) I replaced them and now in 105* heat with the AC on driving in traffic the temp stays at 180* or below.

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'84Z28/'92 305TPI
'92 complete rear suspension/PBR disc/Posi/3:42
Light weight 34.5mm stabilizer bar in front ($10 from wrecking yard)/
"wonder Bar" ($5 from wrecking yard)
23mm sta. bar in rear
Rear RS Springs (slightly softer than my Z28)
comp cam, flowmaster
TB coolantbypass/shutoff valve to heater core
powersteering cooler lines (liberated from another wrecked car of course)
MAT relocated
Ram-Air(home-made) gutted air-box
IROC ground effects/wheels GY245/50's
700R4 superior shift kit/ corvette servo(excellent shift kit btw)
home-made strut tower brace (cost $6)

Rebuilt engine and transplanted it myself.

Love this engine!

freshly painted OCT. 2000 Teal with two white stripes on the hood and deck lid

LOW performance people should drive low performance vehicles!