Thermostat thread

[StockEngine]

Replaced one again. AC is colder. Power improved.

Symptoms: Engine is warmer than normal, Temp gauge didnt move. AC takes 15-30minnutes too cool the cabin. Coolant level dropping. FC was around 6km/L

Fronte Motor Parts - Banawe. scheduling is available. 9am

Look for John

FOCUS

[baludoy]

^ what car and how old bro?

Did you use Pure coolant all the way (oem or otherwise)?

do what you gotta do so you can do what you wanna do

[StockEngine]

^ what car and how old bro?

Did you use Pure coolant all the way (oem or otherwise)?

do what you gotta do so you can do what you wanna do

(2014 Hyundai Elantra 2.0 DIY)

2010 Hyundai Santa fe 2.2 Diesel done at Fronte, Didnt change the coolant yet. konte lng nabawas. topped up with the blue stuff from hyundai. Will flush later on.

AC is cold kahit napaka traffic sa megamall sale [emoji23]

people change radiators and compressors. mas mura naman ang thermostat. [emoji23]

FOCUS

[Archerfish]

How do you know that the engine is warmer than normal if the temperature gauge is not moving?

I hope you don't mind explaining the relationship of the coolant level going down with the thermostat.

[dr. d]

How do you know that the engine is warmer than normal if the temperature gauge is not moving?

I hope you don't mind explaining the relationship of the coolant level going down with the thermostat.

we don't. because we humans can't. "until it's too late."
that's why the temp gauge is there.

when the thermostat is closed (cold engine), the radiator coolant level is... level.
when the thermostat opens up (when engine gets hot), coolant level will either get higher (if the water pump is pushing coolant up into the radiator), or lower (if the water pump is sucking coolant away from the radiator).

[Archerfish]

we don't. because we humans can't.
that's why the temp gauge is there.

when the thermostat is closed (cold engine), the radiator coolant level is... level.
when the thermostat opens up (when engine gets hot), coolant level will either get higher (if the water pump is pushing coolant up into the radiator), or lower (if the water pump is sucking coolant away from the radiator).

Yes, however, *Stockengine mentioned that one of the symptoms of a failing thermostat is when the engine is warmer than usual, that is, when the temperature gauge is not moving.

...

Symptoms: Engine is warmer than normal, Temp gauge didnt move.

...

FOCUS

Or he is referring to another temperature gauge that I'm not familiar with.

Kindly confirm if my understanding is correct about coolant level. If the thermostat is no longer working properly, in example, not opening, then the coolant level will decrease because it will reach the boiling point and evaporate.

[dr. d]

when the thermostat gets stuck in the open position, you won't overheat nor loose coolant. your engine will simply take more time to heat up.

when the thermostat gets stuck in the close position, your engine block will overheat and coolant will boil and evaporate. if that superhot coolant boils its way into the radiator, it might result in boiling that coolant away as well, resulting in a diminished radiator coolant level.
if boiling coolant boils into the overflow cannister, that too, shall boil away.

i think he means, some temp sending units are located in places that require moving coolant. those gauges may not correctly give an accurately high reading, if the coolant isn't circulating.

some cars are "intelligent enough", that the aircon compressor shuts down when the engine is overheating.

[oj88]

No, he means that the temp gauge stays at the same place even if the engine temp varies within its nominal operating temp. It's non-linear.

For most vehicles, the temp gauge stays put in its "normal operating temp" position if the actual coolant temp is between 85°C to 110°C or whereabouts. They made it such so that the driver doesn't panic when the non-graduated temp gauge starts swinging up and down during the course of the trip.

Depending on the vehicle, the temp gauge would only start creeping into the Hot range when the coolant temp gets past the operating temp threshold set inside the ECM. My guess would be 115-120°C onward. At this point, the gauge moves at an exponential rate.

[dr. d]

No, he means that the temp gauge stays at the same place even if the engine temp varies within its nominal operating temp. It's non-linear.

For most vehicles, the temp gauge stays put in its "normal operating temp" position if the actual coolant temp is between 85°C to 110°C or whereabouts. They made it such so that the driver doesn't panic when the non-graduated temp gauge starts swinging up and down during the course of the trip.

Depending on the vehicle, the temp gauge would only start creeping into the Hot range when the coolant temp gets past the operating temp threshold set inside the ECM. My guess would be 115-120°C onward. At this point, the gauge moves at an exponential rate.

i also read his post (#1).
upon reading and re-reading it several times, he probably meant that the temp gauge didn't budge from its overnight cold reading, even as the engine is already noticeably warmer to the touch.

if i may, that is probably true of most cars that still have needle gauges.
my own car's gauge moves up a notch, only after about 1 km.
(but i don't stop to open the hood and feel the engine, to see just how warm it is.)

[oj88]

i also read his post (#1).
upon reading and re-reading it several times, he probably meant that the temp gauge didn't budge from its overnight cold reading, even as the engine is already noticeably warmer to the touch.

if i may, that is probably true of most cars that still have needle gauges.
my own car's gauge moves up a notch, only after about 1 km.

The TS should be able to clarify what he said.

By my understanding, if you have an OBDII gauge that can read the ECT value, you will see that the operating temperature varies wildly. Even so, the temp gauge on your dashboard remains in the same place (usually just below the 1/2 mark).

So my interpretation of what the TS was saying is that, the ECT value is lower now after the thermostat change.

[StockEngine]

Yes, however, *Stockengine mentioned that one of the symptoms of a failing thermostat is when the engine is warmer than usual, that is, when the temperature gauge is not moving.



Or he is referring to another temperature gauge that I'm not familiar with.

Kindly confirm if my understanding is correct about coolant level. If the thermostat is no longer working properly, in example, not opening, then the coolant level will decrease because it will reach the boiling point and evaporate.

there is only one temp gauge. yesterday after we got back from punta fuego the engine area was really warm. "radiant heat" this is the warmth im referring to.

the radiant heat was very bad. when we were idling at fronte grabe the engine area you can feel it talaga. when the mech removed the thermostat housing the coolant was steaming. sabi nga ng mech, its looks new! medyo engot lng sya, all thermostats look new in a sealed system(santa fe). then this evening the engine was warm but not as warm. drove from marikina-bgc-marikina for a client meet.

the santa fe has two cooling fans. one for the radiator and one for the condenser. these two were enough to keep the temperature in check but the radiant heat was bad as well as the fc and the AC performance.



FOCUS

[Archerfish]

Thank you *dr.d for clarifying the thermostat mixed up knowledge. I seldom get my hands dirty so my knowledge is, just knowledge. So I remember my teacher saying,

"When I work with my hands, I understand."

*oj88, you have answered my long time question about that needle position for the temperature gauge. I've been wondering why it "doesn't​ move" when the range is between 85 - 110. Thank you.

Now, I think there is another thermostat. The one I mentioned earlier is the one found inside and is in direct contact with the jacket water. I think the other one is the one responsible for turning on and off the radiator fan. I just don't know if it is called normally as a thermostat.

If this thing is no longer working, then there is the probability that the jacket water will reach the boiling point and evaporate since the fan will not be able to cool the radiator.

[StockEngine]

To add...

I had my Elantra scanned for overheat issues. wala daw, normal kuno! just bought the thermostat and changed it myself. ayun fixed the same issues mentioned. madugo lng coz it required 3+ liters of coolant.

FOCUS

[ninjababez]

ano ba ideal mileage na palitan yun thermostat?

[StockEngine]

ano ba ideal mileage na palitan yun thermostat?

replace as needed. some just dont know when its needed, hence this thread.

FOCUS

[kisshmet]

^wala..just replace it when it fails to function properly..its not fluid that needs to be replaced

Sent from my ASUS Chromebook C202SA using Tapatalk

[oj88]

Now, I think there is another thermostat. The one I mentioned earlier is the one found inside and is in direct contact with the jacket water. I think the other one is the one responsible for turning on and off the radiator fan. I just don't know if it is called normally as a thermostat.

If this thing is no longer working, then there is the probability that the jacket water will reach the boiling point and evaporate since the fan will not be able to cool the radiator.

Don't mix thermostats with thermoswitches and engine coolant temp sensors.

Thermostat Valve: A mechanical device that is temperature-controlled that starts routing coolant to the radiator (>82°C) or feeds it back to the engine (<80°C) to regulate the coolant temp

Thermoswitch: A mechanical switch that is typically installed at the bottom tank of the radiator which turns on the radiator fan(s) when a certain temp is reached (>85-95°C) and turns off when the temp gets below a certain point (73-75°C)

ECT sensors or temp sender units: The engine coolant temp sensor is an electronic device that varies its internal resistance based on the temperature it's exposed to. The ECU interprets the resistance and converts it to a temperature value that it uses to adjust A/F ratio, idling speed, shift points (A/T), A/C operation, and other engine parameters. You don't typically see the actual value the ECT sensor is giving without an OBDII tool as the ECU abstracts the operation of the temp gauge or temp warning lights. In other words, the temp gauge on your dash is showing what the ECU wants you to see. It does not necessarily reflect the actual temp as seen by the ECT sensor.

Many vehicles don't have a thermoswitch, and instead uses another ECT sensor on the radiator with the ECU commanding the radiator fans when to turn on and off.

[Archerfish]

Don't mix thermostats with thermoswitches and engine coolant temp sensors.

Thermostat Valve: A mechanical device that is temperature-controlled that starts routing coolant to the radiator (>82°C) or feeds it back to the engine (85-95°C) and turns off when the temp gets below a certain point (73-75°C)

ECT sensors or temp sender units: The engine coolant temp sensor is an electronic device that varies its internal resistance based on the temperature it's exposed to. The ECU interprets the resistance and converts it to a temperature value that it uses to adjust A/F ratio, idling speed, shift points (A/T), A/C operation, and other engine parameters. You don't typically see the actual value the ECT sensor is giving without an OBDII tool as the ECU abstracts the operation of the temp gauge or temp warning lights. In other words, the temp gauge on your dash is showing what the ECU wants you to see. It does not necessarily reflect the actual temp as seen by the ECT sensor.

Many vehicles don't have a thermoswitch, and instead uses another ECT sensor on the radiator with the ECU commanding the radiator fans when to turn on and off.

Thank you for taking your time to clarify these things. Yes, I mixed it up because of my simple definition of a thermostat as an instrument that measures temperature​ and acts like an on-off switch. I think these things are not found in the Owner's Manual. And my guess about this thermoswitch is an RTD.

Now, what is the relationship of this failure in the mechanical thermostat with the jacket water loss as mentioned earlier?

[StockEngine]

daming bagong vios na nakabukas ang hood. partially open kaya?

FOCUS

[brushless]

daming bagong vios na nakabukas ang hood. partially open kaya?

FOCUS

There's already the front grille for air flow to keep the engine bay cool. Why the need to do that? Design flaw? It's not a sealed system.