01 Pontiac Montana...Engine dies upon reaching

Gasket problem 3.4 engine.

If your vehicle doesn't actually overheat, just getting hot, I think that's the normal behaviour for these cars. My 03 AWD behaves the same way. When driving uphill, especialy when towing, the temperature rises close to the red marking, but I have never experienced it overheating. I think that the temperature has to rise much over the normal driving temperature to activate the two electric fans.

Is the engine reaching normal operating temp, and is the cooling system full of liquid coolant ?

Your coil that allows air to pass through for A/C or heat could be plugged or the thermostat is sticking.

Possible bad sending unit or shorted sending unit wiring.

which oil sending did you change .there is 2 on that motor. 1 is next to the oil filter and the other is in the oil pan next to the oil plug

f your heater is not heating your vehicle adequately, it could be the result of a few different things:


1) Your thermostat could be stuck in an open position. This will result in your vehicle being underheated. Typically, a thermostat opens only when an engine reaches a certain operating temperature. If a thermostat is stuck in the open position, radiator coolant flows into an engine before it reaches normal operating temperature. This prevents adequate engine warming and results in engine underheating. DIY repair costs: $5-$10


2) Your radiator could be low on coolant. If this is found to be the cause, then you will have to inspect your coolant system for leaks. Depending upon what type of leak your vehicle has (if this is found to be the case), I would have this repair done by a shop unless it is something reasonable simple to fix like a water pump leaking. A replacment water pump will run you $70-$100.

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Where do you hear a valve or flapper moving??? Behind the dash ( instrument panel ) It sounds to like you have a electrical problem , not overheating problem . You need to test to see what the real engine temp. is . Also have vehicle checked for DTC'S - diagnostic trouble codes ,Sounds like A/C is kicking on , the flaper noise you hear is probably the temp actuator inside the dash . You can buy the tool in the video at harbor freight cheap. Point it at upper radiator hose ,near the engine . The IPC illuminates the hot coolant temperature indicator in the message center when the IPC determines that the coolant temperature is greater than 128°C (262°F). The IPC receives a class 2 message from the PCM indicating the coolant temperature. Are you getting any such message ?
How to Use an Infrared Thermometer to Diagnose Car Problems

before u replace any parts u need to have the electronic engine control tested for trouble codes, this is the 1st thing that any shop does to know where to start the repair and diagnosis. Most likely u have a defective crankshaft position sensor, but have the test run..

1391 is lose off cranksensor or cam sensor like code 340 i would by a cam sensor for that code.356 sounds like a bad coil on #6 which there are one per cylinder .dont worry about code 432 for now.