What is thermostat valve and its working?

[Alichand999]

aoa
Hi all pakwheelers plz tell me the function of thermostate valve and what function in petrol and diesel engines should this be removed or not in petrol engines many machenic says it should be removed and many says it shoud not be removed please tell should i remove my cars thermostate valve or not my car is mehran.
Thanks all.

[Zaheer_Zaidi]

thermostat valve is used to remain eng heat level constant i.e with auto fan thermostat valve help to remain heat at half, obviously u hav see this.... whenever fan switches on, it means the hot water inside the engine transfered to radiator n half boiled water transfered to engine to keep constant the engine heat level... tat much heat level helps engine to giv its best performance... it can be removed...

[hash4u]

https://www.pakwheels.com/forums/engine-accessories/29376-thermostat-valve

[levin]

it takes engine to correct operating temperature faster. by removing it you will run yr engine colder for longer time, resulting in wear out of piston rings.

a defination of a mechanic is someone who is qualified to operate on car, not someone who learnt on hands on experience from others.

chk yr mechanic's qualification before letting him work on yr car.

[BlueHorn]

here you go!

Let me google that for you

[Xulfiqar]

The favourite of desi mechanics is to throw away the Tstat. WHY
Firstly their ustaads (jaahil btw) were used to working on non functional scrap metal of cars, transferred this knowledge to the NOW CURRENTLY WORKING mechanics. Couple this to bad practices on the customers expense - they remove the valve - to earn quick easy money with no heed to the aftereffects (short engine life and a myriad of other problems) - e.g. in EFI the ECU will not go into closed loop unless the coolant gets to proper operating temperature, most electronic automatics will not shift into overdrive or convertor lockup unless the coolant is at temperature, (usually the same mechanic will recommend rebuilding the transmission or replacing with a used scrapyard piece - to make more money out of the poor unknowing customer)

I can bet you a million rupees today regular desi ask a mechanic how the cooling system works and what is the function of the radiator cap, they will have no idea.

As levin mentioned the thermostat is there for a function - to make the engine quickly come to operating temperature and stay there. The poster above who mentions boiling water in the system does not have the full concept of why the radiator cap increases pressure.

In a nutshell, Never remove the thermostat to band aid a problem, its there for a function, if you wish purge air quickly from your mehran, bolan or whatever 0.8 litre oldschool suzuki engine, drill a little hole in the T stat base plate, it will ensure that your system does not get air locked and that foam can pass though (foaming causes cavitation). And if your system is foaming the T-stat will nearly shut as it needs a solid contact with coolant to function)

hope you got the point

[Vaqas1]

Agree 100% with Xulfiqar bhai but I will also add if you never had Thermostat or auto fan in your car than suddenly switching to TSTATE and Auto fan might give you initial issues.

Like with no Tstate and no Auto fan your cooling system might be running without any pressure in it so suddenly making it pressurised might cause some leaks.

Why do we have these cooling system pressurised? The normal boiling temp or water is 100c but if you can pressurised this water in your cooling system you can increase the boiling temp of water to 110c or even more depending on the radiator cap you use and your cooling system. Concept is same like pressure cooker at your home

[talhawaleed]

No I don't think so that it should give any issue.

Nicely explained the point by every one.

Normally you never find out if your car autually has a thermostat valve or not

Or some stupid mechanic has taken it out without informing you.

Is their any simple test to find out about this.

[talhawaleed]

Radiator cap is meant to control pressure not thermostat valve.

Thermostat only ensures that you engine quickly reaches the optimum

Working temperature.

[mushahid]

I have asked few mechanics why thermostat should not be used and most of them dont have any answer except that it is only in new cars which have strong engine and old cars have weak engine.
One mechanic told me that using thermostat create pressure in the pipes which result in leak of water.

I think the reason for removing thermostat is that many peoples use plain water in the radiator instead of coolant. when engine heatup , water start boiling, turns into steam and can escape from the pipes. This results in reducing of water level and people thinks that water is leaking.

So if you are using a thermostat then always use coolant in radiator. Coolant have high boiling point and can tolerate a lot of heat without turning into steam.

[imranbhatti]

So if you are using a thermostat then always use coolant in radiator. Coolant have high boiling point and can tolerate a lot of heat without turning into steam.

It means in presence of coolant, cooling system faces more pressure & heat within it so the probabilty of leaking pipes etc must be increased.

In fact its quite hectic for mechanics to isolate & remove minute issues so usualy they blaim the tehrmostat valve & auto fan switch.
In most of the cases poor cooling system it self causes reduction of water/coolant & causes engine heat up & mechanic portray it as engine is weak & creating more heat & cuasing boiling of water etc.

[Skill]

One way to know is to start a cold engine and feel the upper radiator hose. You should feel no coolant moving inside the hose until the engine starts to get warm.
After several minutes, you should feel a sudden surge of hot coolant when the thermostat opens.

[Skill]

One way to know is to start a cold engine and feel the upper radiator hose. You should feel no coolant moving inside the hose until the engine starts to get warm.
After several minutes, you should feel a sudden surge of hot coolant when the thermostat opens..

.

[Xulfiqar]

I have asked few mechanics why thermostat should not be used and most of them dont have any answer except that it is only in new cars which have strong engine and old cars have weak engine.
One mechanic told me that using thermostat create pressure in the pipes which result in leak of water.

I think the reason for removing thermostat is that many peoples use plain water in the radiator instead of coolant. when engine heatup , water start boiling, turns into steam and can escape from the pipes. This results in reducing of water level and people thinks that water is leaking.

So if you are using a thermostat then always use coolant in radiator. Coolant have high boiling point and can tolerate a lot of heat without turning into steam.

Do not let those same mechanics work on your car.. They are not qualified. If an engine cannot hold coolant under pressure - there is something wrong which needs to be fixed quickly.

Yes I know its hectic for most mechanics to peer down into a hot engine to find leaks, do I devised this technique in my shop to work on a cool engine and find the leaks.

remove the Tstat and install elbow back, completely drain coolant from the system - install rigged radiator cap with air line fitting - apply vacuum - it should hold - if not, release vacuum then apply pressure of 18 psi, check the whole system for leaks with soap bubble method externally and then air check method for the cylinders and crankcase vents. Your leak would definitely show up. Repair leak, install Tstat after verifying operation in hot water, fill with proper coolant/water mix and live in peace.

You can use plain water in the cooling system if the system is slightly oversized, but be prepared to acid clean it every 6 months.

[Ghuncha]

Do not let those same mechanics work on your car.. They are not qualified. If an engine cannot hold coolant under pressure - there is something wrong which needs to be fixed quickly.

Yes I know its hectic for most mechanics to peer down into a hot engine to find leaks, do I devised this technique in my shop to work on a cool engine and find the leaks.

remove the Tstat and install elbow back, completely drain coolant from the system - install rigged radiator cap with air line fitting - apply vacuum - it should hold - if not, release vacuum then apply pressure of 18 psi, check the whole system for leaks with soap bubble method externally and then air check method for the cylinders and crankcase vents. Your leak would definitely show up. Repair leak, install Tstat after verifying operation in hot water, fill with proper coolant/water mix and live in peace.

You can use plain water in the cooling system if the system is slightly oversized, but be prepared to acid clean it every 6 months.

the specific heat of water, the energy required to raise the temp by given amount of water is more than coolant, so i hae read that you need more flow rate in coolant as compared to water?

am i talking sense?

[dms664]

https://www.pakwheels.com/forums/engine-transmission-powertrain/146244-wts-function-thermostat-wall

[Xulfiqar]

the specific heat of water, the energy required to raise the temp by given amount of water is more than coolant, so i hae read that you need more flow rate in coolant as compared to water?

am i talking sense?

yes and thats why we use a max of 50% conc of EG coolant. This charecter can be more understood as soaking up the heat while moving, water picks it up excellently but has its own problems of scale corrossion and evaporation.

[auree1255]

benefited from this thread today. Thanks to all!

[Dongskie]

Normally you never find out if your car autually has a thermostat valve or not

Actually you can, on cold start run the engine and open the radiator cap, rev the enigne a bit and if the water flowes like a river, then you don't have a TStat..

[Dongskie]

..... e.g. in EFI the ECU will not go into closed loop unless the coolant gets to proper operating temperature, most electronic automatics will not shift into overdrive or convertor lockup unless the coolant is at temperature

Is this related? my dad's Isuzu Gemini with 3speed A/T suffered this problem back in 1992, the tstat was removed by the Petrol Shop mechanic after an overheat issue, then a week later the tranny started to act strangely, mostly would take a long time to shift and often not shift to 3rd gear at all.

I do remember it was perfectly working before the Petrol Station Issue, I also noticed that an ATF tube runs inside the bottom of the radiator to and from the tranny..