Ke5070

Im trying to figure out if my K24 is running hot. Getting a temp reading from my OBD2 of 214 but which sensor is that coming from? ECT1 at the block or ECT2 at the radiator?

And which sensor triggers the fans at low speed (and at what temp) and at high speed circuit (and at what temp)?

motoxxxman

ecu uses ect1 to determine coolant temp for all running conditions. and 214 is normal.
fans use ect2 at the radiator.

Ke5070

motoxxxman

99% of all automotive engines the coolant flows into the top of the radiator and out of the bottom of the radiator. This is to prevent any air travelling back into the motor.

JRCivic1

Honda is the 1%... they go the other way. Into the bottom of the radiator, then up and out of the top of the radiator and into the engine.

drg007

iTrader: (2)

are you 100% sure on the fact.

drg007

iTrader: (2)

Honda Cooling Systems - Honda Tuning Magazine

JRCivic1

Yes, I am sure. The article is completely incorrect... other than it says that it has a water pump, thermostat, water jacket and a radiator. Let's examine a few of the incorrect details... shall we ?!?

Quote from the SS article: (My corrections are in bold)

The process isn't terribly complex. It starts with a belt-driven water pump that pushes (the proper term here would be PULLS) about six or seven quarts of coolant (typically a mixture of water and some sort of antifreeze) through the engine block and around the cylinders where it absorbs heat. Coolant then flows through passages (out of the block and across the back of the block in the water pipe) that correspond with the cylinder head (this happens when the thermostat is closed and the coolant bypass hose routes coolant back into the cylinder head to maintain some circulation since no flow is coming from the radiator), past (to) the thermostat housing, through a series of tubes and hoses, and into the radiator (does the thermostat housing connect to the upper radiator port ??? NOPE, it goes to the LOWER radiator port) through its upper (Lower) port where heat is released to the outside air. Once coolant exits the radiator's lower (Upper) port, it's directed back (into the cylinder head and) toward the water pump to start all over. In some cases, individual circuits may direct fluid from the cylinder head into a heater core, engine oil cooler, or transmission oil cooler before routing it back to the water pump.

Everyone can test this at home to verify the coolant flow. Crank the car cold and let it idle. As the engine runs, heat will build up in the water jacket and cylinder head while the thermostat is still closed. The coolant bypass hose and the upper radiator hose will begin to get hotter and hotter... the bypass hose is recycling the heated water from within the block and head, so it will get warm/hot first (and if the heater core is open, those hoses will grow warm like the bypass hose). The upper radiator hose will get warm because of radiant heat from the water within the cylinder head... if you pay close attention while the engine warms up, the hose will be warm close to the head BEFORE the radiator gets warm at the top. Since the thermostat is closed, the lower radiator hose will remain cold until it reaches the opening temperature, then and only then, does the coolant path change. When the thermostat opens, the coolant bypass hose port is blocked inside the thermostat housing and coolant now flows through the thermostat and down to the radiator to be cooled. Pushing fluid into the bottom of the radiator forces fluid out of the top and into the cylinder head. This is the normal operation path once the vehicle has been brought up to operating temperature.

motoxxxman

JR, I know you're not an idiot. I do have to say here though that you're wrong on this one. Yes, hondas do follow suit with most other engines in that the coolant does in fact flow into the top of the radiator and out of the bottom of the radiator. The only difference with most 92+ honda motors is the thermostat is actually on the lower radiator hose. But that does not mean the coolant flow is into the bottom of the radiator. The thermostat just operates a slightly different way. Honda put it on the lower hose to prevent fluctuating coolant temps.
The coolant in hondas does flow in this order though: engine -> upper radiator hose -> radiator -> lower radiator hose -> thermostat -> engine.

JRCivic1

Thanks for the vote of confidence motoxxxman... on this one, we are gonna have to just agree to disagree my friend.