Temperature light red, coolant full? - Cars & Trucks

Check the coolant level.
The radiator must be full, coolant should be mix of 50/50.
If it is full, and stays full when overheating, the most common cause is a defective cooling fan.
One of your electric radiator fans is for your A/C and one is for the radiator cooling
Any time the temperature gauge/ or red light comes on, that fan should be running.
Raise the hood and look the next time it overheats, and if no fans are running, you need get it fixed quick, lest you blow a head gasket.
The problem could be either the electric fan motor, or the sensor switch that screws into the engine block.
If the coolant stays full, and the fans are running, you may have a stuck or closed thermostat.
God bless your efforts.

have you checked the fuse and also the relay.

Usually the problem with no heat and overheating is low coolant, thermostat, or a faulty water pump impeller.
The radiator may not be full of liquid coolant, or the pump may not be moving the coolant thru the block.

check coolant level could be too low allowing air in the cooling system causing air pocket in engine around the engine coolant sensor.coolant sensor needs to be in hot coolant so it will cause the cooling fan to come on at a set temperature.make sure coolant correct level and the coolant level in the cooling overflow jug should be at full cold mark.the cooling overflow jug should never be empty,if you see empty cooling overflow jug air got in the cooling system so make sure when engine cold every time raise hood make sure cooling overflow jug coolant level at full cold mark.if jug stay empty you have cooling leak.so replace radiator cap,if coolant level all good,i would replace the engine coolant temperature and thermostat.when your car come to a long stop or driving along long line of slow moving traffic the engine coolant blower motor should running if not have vechicle code scan for faulty coolant fan motor control module.or ecm problems.

That the temperature gauge,you engine is cold,and goes off when the engine is warm and at its optimal performance temperature,now if it goes red when your driving then thats a warning its overheating,

yea they are right right undo the hoses from the coolant container to to the radiator and the hose from the radiator to the engine and let it all drain out then put it back on and put some new radiator fluid in the radiator until ist full and then put some more in the container for extra make sure to put both hoses back on

I've had this happen on my Boxster as well. Couple of things to look (and smell) for:
Leaks, look around the water pump under the engine, around of the rear firewall (between the trunk and the engine compartment) and the trunk. You can usally smell the coolant. The coolant tanks are notorious for cracking and leaking.

Air in the coolant system. The coolant has to run the length of the car from the trunk to the engine to the radiators in front of the front wheels and back again. If there is air in the system it will cause the car to run hot. A mechanic can bleed the system with a vacuum or you can do it the more tedious but cheaper way:
Turn on the heat on full
Add coolant to the full mark on the tank
Bring the car (engine) up to temperature by driving or idling. You want the thermostat to fully open.
Let the coolant come down in temperature in order to open the cap to the coolant tank without hurting yourself and fill the coolant tank to the full mark.
Go through this process repeatly unitl the coolant tank does not need refilling. There are several articles on the Boxster forums.

possible water pump impeller broken

fan relay is under the frame on the left by the fans. but most likely the fans themselves have gone bad check the fuse panel on top of the battery see if it is burned or blown fuse this is caused by the fans going from stop to high speed to many times. you will flat 40 or 50 amp flat blade fuse and both fans sorry for bad news

Look for a loose connection to the temperature sender unit on the motor.
If all connections OK, you may need a new temp sender unit.