2002 still getting hot after changing everything
 

My problem started a year ago getting hot on the freeway. It never got to 260, but was way to close. Let it cool and nursed it home with many breaks. It had always run 195 since it was new. Changed the thermostat and all seemed good. Until lately, i can't go 2 miles without it getting hot. So new thermostat again, still hot, new radiator, still hot, REBUILT head, new gasket, new bolts, still hot, new water pump, still hot, hoses are not hard, out of shape, or sucked shut. No bubbles in the surge tank so head job is OK. I never see the fan come on unless the ac is on, which in AZ. is all the time anyway. 60 or so on the freeway it gets hot, drop into 3rd and hold 3200 rpm and the temp goes to 195 or just under. At a stop light temp goes up till i hold 3200 rpm in neutral, drops to 195 again. Help. What have i missed? its a 2002 cavalier 2.2 ohv 4 cyl. I'm going to get the attention of every law enforcement officer in the area if this keeps up. I dont like the look in my wifes eyes as she's looking at new cars we really cant afford...

New thermostat does not mean good thermostat. I'd try changing it one more time, maybe different one.

How much did you spend on your new surge cap?

What brand is it? I'm merely assuming you have the new

type system with no cap on the radiator?

If it's a two fan, one comes on with A/C, the other is a temp sensor controlled, that'd be where I'd look.

The cap on the surge tank is 10 months old, replaced with first thermostat from Napa (now on #3). Haven't even been able to go anywhere since the new radiator. Still gets hot. The system only has 1 fan. The hot coolant splits somewhere and most goes through the radiator and back through the thermostat to the pump. The 1" split off hose goes straight to the back sensor area of the thermostat and on to the pump. The thermostat, 1" hose and pump make a "Y" like configuration. The top radiator hose is to hot to hold, same with the 1" hose, the lower radiator hose at the front of the thermostat feels like warm bath water. When the car cools down at 3,200 rpm it drops to the 195 degree of the thermostat. Rigging the fan to run full time didn't cool the engine. I'm ready to restrict the flow from the 1' hose so it pulls more from the radiator. Going to Napa for #4 stat tomorrow.

see post #4

Did some testing in my garage at 80*.
#1 back flushed the Radiator and Engine. #2 Rigged a manual switch for the one and only fan. #3 gutted the old t stat and installed. Ran the engine for 30 minutes without the fan to reach 195*. Turned on the fan and the AC for giggles. 20 minutes later it was 122* and still dropping. Great, everything works as it should.
Retest
Installed #4 T Stat, Run 5 minutes without fan and temp is 195*, feeling the hoses the upper is now getting hot near the radiator (T Stat opened) lower is bath water warm. 5 minutes with the fan on no air and temp was 215* and climbing. Put a c clamp on the bypass hose to make it pull more water through the radiator and temp still climbing past 230*. I'm starting to think the wife has the right idea almost $600 and 1 month later. Like all the other people with these problems it used to always run 195* at all times.

How are you measuring the temperature, by the I/P cluster? Maybe the gauge is malfunctioning. Have you scanned for what the PCM thinks the ECT is at?

Just off the cluster. When it said 260* last fall it was sizzling and cracking and smelled hot. Also the coolant starts flowing through the top hose at 195*(can feel the hose getting hot after the t stat opens around that temp). Just got back from Chevrolet. they said $125 to diagnose plus parts and labor to fix it. Also had never heard of a heating problem in cavaliers. I hsve not had it scanned yet.
For now no stat, manual fan, running around below 145*. I've got a "Dodge"mechanic friend checking around for me. This is getting personal.

The thermostat (working) acts as a flow restrictor so you have some retention time in the radiator. That needs reinstalled (working)