Air in the cooling system won't help things.
OEM thermostat currently in use, versus the mismatched, non-bypassed thermostat missing the jiggle valve?
Just to add to the fray of questions people might want answered.
GSTwithPSI has a very valid point about where the overheating is becoming the issue, tune being way off will lend to overheating, much like cooling system woes.
Wop's point about the Scirocco rad, is also very valid, as many people have used that setup, with the remainder of the control system operating within spec and able to maintain proper temps.
Thermostats have to be there to create a flow restriction, and allow the coolant to cycle into the radiator and take it's time to be cooled before going back into the motor. Remove the restriction and you get an overflow, and complete lack of time to cool the fluid while it is now, albeit for too short a period of time, within the radiator before being sucked back into the water pump/engine.
Thermostats and the saturation/radiation of heat from the radiator all play a tricky balance.
It's a bizarre process to try and put into words. Sometimes this is best left in text books.
So, what style of thermostat is installed and how's that tune?
Can you log what the AFR comes in at, when the car is overheating?
Would your logger read more accurately than your dash cluster? They are two separate sensors that send out signals after all.
Most properly functioning engines overheat at idle due to lower flow of air over the radiator/condenser, and or sticking thermostat's (they don't open properly given the temperatures that they are supposed to be governed by - but fail to correspond to).
Interesting blurb I saw posted on the google search:
Quote:
first of all, there needs to be a thermostat in the system. IF you removed it thinking it would run cooler without it your wrong. There needs to be a restriction in the cooling system to slow the flow of coolant through the radiator. If there is no restriction, ie no thermostat, the coolant is passed through the radiator too fast to transfer any of the heat to the cooling fins. typically, if a vehicle overheats while driving and not at idle it's because the coolant is low. see above. when the engine is at idle the water pump is slowed way down so the coolant has time to transfer the heat off to the cooling fins of the radiator. also there is no load on the engine while idling. If you still believe you need to run your cooling system without a thermostat, then take the old thermostat and cut apart the wax pellet and discard. replace the rest of the thermostat back in the system to provide the necessary flow restriction. You can also use a flat washer that is the same diameter of the thermostat to sit in the housing. the hole in the center of the washer will restrict the coolant flow. this is the first thing I woult tell any customer of mine to do. if there are no leaks, the engine could be consuming the coolant internally. Or, you could have a cracked block or head allowing combustion gases to enter the cooling system and this is what you are seeing from the expansion tank. A good pressure test of the cooling system is in order. You can also purchase what they call a block tester. It uses a test fluid to check for combustion gases in the coolant. This will tell you if you have a cracked block or head, or a bad head gasket. check to make sure your heater core is not plugged also. both hoses should be hot to the touch, one slightly cooler than the other.
Source:
ase master certified auto technician
In summation,
Everyone needs a little jiggle in their life!!!
Click for non-OEM thermostat with jiggle valve
