Temperrature Gauge - Thermostat

Qwerty · June 13, 2007

Hi,

I have a toyota corolla (AE100) car. When I start the car and drive in the morning, it takes more than 10 minutes (sometimes around 15 mins) for the temperature gauge to come to the mid point (operating temperature). Is this a normal behaviour? Or is this the sign of 'thermostat stuck open'? If so, what other symptoms I can observe from the car?

Please advice.

Thanks.

Tikiri · June 13, 2007

Hi, you must indicate, whether this is with Air con on or off, if with A/c on there is something wrong which you need to get it checked with a good electrician, also pls check whether your fans are given direct at any point, if the fans are given direct you could experience this too, (if so you need to correct that as fans are not meant to be like that )

Qwerty · June 13, 2007

Hi, you must indicate, whether this is with Air con on or off, if with A/c on there is something wrong which you need to get it checked with a good electrician, also pls check whether your fans are given direct at any point, if the fans are given direct you could experience this too, (if so you need to correct that as fans are not meant to be like that )

Thanks for the reply.

This is with the A/C is on. When the A/C is switched off the time taken is lesser.

Can you please explain a bit more about the fan thing because I didn't understand it well.

lakshank · June 13, 2007

Engine needs a certain temperature to operate and perform at its optimum. thermostat is the unit which does control the engine temperature...when the engine gets too warm it allows the water or coolant to circulate in the radiator and when the temperature is not enough it blocks the circulation and makes it more hot. this is the principal of having a thermostat.

most of our local mechanics remove the thermostat in order to overcome overheating problems...overheating could result from various other problems and its a vast area to discuss.

there is another method our mechanics do to rectify the same problem.

I hope Qwerty knows the duty of the fan. it cools down the boiling water inside the radiator. there are mainly 2 types of radiator fans. engine driven fans and electric fans. most rear wheel drive vehicles have this type of fans. fan is driven by the engine and connected to one of the pulleys. most modern vehicles are equipped with a viscous coupling which means the fan works according to the engine heat. this is done by a glue type thing inside the viscous coupling unit and it gets thicker as the engine warms up and vice versa. our local mechanics lock the fan by using a screw through the viscous unit and then it will be always running with the engine speed. at all circumstances this speed is greater than the original rotation speed with the viscous unit.

the other type is electric fans which is driven by a motor. this is connected to the thermostat and the fans comes on when the engine gets warmer. I have seen in lot of vehicles they have directly connected the fan bypassing the thermostat. as you turn the ignition on the fan starts to work.

both the ways are ok to rectify the overheating problem, but it is not the bset thing to do. get a proper mechanic to look at the problem and find the cause for the overheating. not running at the required temperature would result in low engine performance.

its quite normal that in the mornings it takes a while for the gauge to reach its normal operating temperature. it looks like you are under the impression that every car has the same operating temperature which is mid point according to you. it is not necessarily need to be like that.

Edited June 13, 2007 by lakshank

Qwerty · June 13, 2007

Engine needs a certain temperature to operate and perform at its optimum. thermostat is the unit which does control the engine temperature...when the engine gets too warm it allows the water or coolant to circulate in the radiator and when the temperature is not enough it blocks the circulation and makes it more hot. this is the principal of having a thermostat.

most of our local mechanics remove the thermostat in order to overcome overheating problems...overheating could result from various other problems and its a vast area to discuss.

there is another method our mechanics do to rectify the same problem.

I hope Qwerty knows the duty of the fan. it cools down the boiling water inside the radiator. there are mainly 2 types of radiator fans. engine driven fans and electric fans. most rear wheel drive vehicles have this type of fans. fan is driven by the engine and connected to one of the pulleys. most modern vehicles are equipped with a viscous coupling which means the fan works according to the engine heat. this is done by a glue type thing inside the viscous coupling unit and it gets thicker as the engine warms up and vice versa. our local mechanics lock the fan by using a screw through the viscous unit and then it will be always running with the engine speed. at all circumstances this speed is greater than the original rotation speed with the viscous unit.

the other type is electric fans which is driven by a motor. this is connected to the thermostat and the fans comes on when the engine gets warmer. I have seen in lot of vehicles they have directly connected the fan bypassing the thermostat. as you turn the ignition on the fan starts to work.

both the ways are ok to rectify the overheating problem, but it is not the bset thing to do. get a proper mechanic to look at the problem and find the cause for the overheating. not running at the required temperature would result in low engine performance.

its quite normal that in the mornings it takes a while for the gauge to reach its normal operating temperature. it looks like you are under the impression that every car has the same operating temperature which is mid point according to you. it is not necessarily need to be like that.

Thanks for such descriptive info.

About the fan, the electric fan seems to work when the engine is hot. It is not ON always (in my car). So, I think the fan problem would not be there.

But my doubt is that whether the thermostat is open always. That is, the radiator coolant circulates since I start the engine which will increase the time to reach the operating temperature. Won't this be a case?

And I am worried that, since the engine runs cold for a longer time period, this may consume more fuel.

Saturn · June 13, 2007

Hi,

I have a toyota corolla (AE100) car. When I start the car and drive in the morning, it takes more than 10 minutes (sometimes around 15 mins) for the temperature gauge to come to the mid point (operating temperature). Is this a normal behaviour? Or is this the sign of 'thermostat stuck open'? If so, what other symptoms I can observe from the car?

Please advice.

Thanks.

I think theres a valve which prevents water being circulated till the engine warms up - most people remove this valve in Sri Lanka. when it is removed, the car may take a bit longer to warm up.

I'd suggest you to just use the car carefully (not rev the enging too high or load it up too much) till it's fully warmed up. Alternatively (if the valve has been removed) you can get a new one installed.

Check if your fan is wired to run 100% (does it turn on when you start the car), or only when the radiator is hot? If the fan is running always, it can also prevent the car from reaching operating temperature sooner.

Edited June 13, 2007 by Saturn

Qwerty · June 13, 2007

Thanks for the replies. The fan works ok. To make sure the problem is with the valve/thermostat I need to know how long a normal (toyota) car takes to warm up. Mine is around 10 yrs old.

Can you people give your car readings (how many minutes it takes for the engine to warm up)?

Tikiri · June 13, 2007

Thanks for the reply.

This is with the A/C is on. When the A/C is switched off the time taken is lesser.

Can you please explain a bit more about the fan thing because I didn't understand it well.

Hi, You have got an excellent description from lashank, also bear in mind some cars (including toyota) got a dual speed fans as well, this means when radiator is too hot the fan works faster, then cools down, and work at normal level. When this sensor doesn't work usuallyit tends to heatup, but you never know whther its a rare case of vise versa, my past experinece on AE100 is withing about 10 mins if its morning with a/c on it comes to teh operating level which is like inbetween half and quarter, best is you get the car checked whether your termostat is removed , correct fans are in place, (by any chance someone has fixed a fan that is more cooling as a replacement) etc,, so get it checked what ever it is worth. Good luck

Kim · June 14, 2007

mines taken around 3 - 4 mins for the meter to go up.

i always start the car and leave it for around 5 mins so that the engine heats up and would be in order with the oils and motors running

Is there anything like that you should wait till the temp meter goes up to put on the A/C? i mean when started in the morning?

ppl say the cars are 10 - 12 years old and this is bull shit so that NOT Applicable or NO USE. but then can a person wake up in the morning and suddenly run fast? or start working on something? normally you wake up, drink something, do the needful and only then ready for a action? isn't it? any comments?

Qwerty · June 14, 2007

Thanks for all the replies.

Can I have more inputs on the time? especially the time taken in morning.

Saturn · June 14, 2007

Thanks for all the replies.

Can I have more inputs on the time? especially the time taken in morning.

Can you confirm that your fan's are OFF when you start in the morning, till the vehicle warms up?

start in the morning, and pop the hood, physically inspect if the fan's are running.

If they are running then they could have been wired to run directly (which could cause your car to take longer to warm up).

Edited June 14, 2007 by Saturn

Archon · June 22, 2007

mines taken around 3 - 4 mins for the meter to go up.

Is there anything like that you should wait till the temp meter goes up to put on the A/C? i mean when started in the morning?

ppl say the cars are 10 - 12 years old and this is bull shit so that NOT Applicable or NO USE. but then can a person wake up in the morning and suddenly run fast? or start working on something? normally you wake up, drink something, do the needful and only then ready for a action? isn't it? any comments?

Err... as far as i know...you don’t have to wait until the engine heats up (true for naturally aspirated)! but if your car has a turbo charger you may have to wait until it revs up to its normal idling rpm... the story behind this is that, the turbo fans take time to spin to its normal rpm..so! if you starts to get going before it charged up ........ your engine will experience inefficient combustion…

the same rule applies when you turn off your turbo engine...coz turbo fans needs to get slow down before the oil pressure goes down. if not the bearings of the fan shaft will get damaged...(normally turbo fans spins at 15,000rpm when idling << depends on the type/model) so that is why modern turbo charged vehicles comes with a turbo timer....or you can buy a turbo timer from the market.... turbo timer keeps your engine running (for few seconds) even if you turn off the engine until the turbo spines down... so sometimes ppl will come to you and say "sir! you've forgot to turn off your engine at the park"

But if you don’t have turbos ... no need to worry! Supercharged engines and naturally aspirated engines are ready to go from the moment they started....but if you could wait for 5-8 sec after the initial start will be a good habit coz oil needs to be supplied everywhere!

Archon :alc:

Memphis · June 23, 2007

mines taken around 3 - 4 mins for the meter to go up.

i always start the car and leave it for around 5 mins so that the engine heats up and would be in order with the oils and motors running

Is there anything like that you should wait till the temp meter goes up to put on the A/C? i mean when started in the morning?

ppl say the cars are 10 - 12 years old and this is bull shit so that NOT Applicable or NO USE. but then can a person wake up in the morning and suddenly run fast? or start working on something? normally you wake up, drink something, do the needful and only then ready for a action? isn't it? any comments?

Here's my observation today in the morning ..

Start with AC off -> Fan off -> Comes on when the engine gets hot

Start with AC on -> Fan starts simultaneously

Hope this helps