How Important Is The Thermostat?

[VVTi]

During a recent trip to the hills, I noticed a few issues with the Forester. Notably black smoke, fume smell and more than usual fuel burn. Thinking that the drop in temp and the rise in altitude could be a factor I ignored it. Had a nagging feeling that the the engine was running rich, so went on to clear all the possible guilty parties. MAF, MAP, O2 Sensor, filters, etc. Had a diagnostic done and all were fine.

Decided to pop the thermostat housing to see if the thermostat was there... SURPRISE... it wasn't... and there you have it.

The thermostat is a crucial part in an engine. In fact, the life and health of the engine actually depends on it. Why our maka baases remove it is beyond me. Asked Senok if they are carrying the part and was surprised to find out that they don’t since no one buys it!!!! So I bought a similar thermostat and put it in, and things just sorted themselves out. No black smoke, no petrol smell. Nothing and the car actually responds slightly better (Could be the Placebo effect too). Ordered the original 78 degree unit and once it arrives will pop it in.

What I am trying to say here is that, it is crucial that all of you INSIST that the thermostat is ins your cars. Don't let your mechanic or whoever tell you otherwise. The durability of your engine depends on it. The engine needs to run at a certain temperature. removing the thermostat forces the car to run cooler, which is NOT GOOD. If it gets blocked and you overheat, replace it. Don't let anyone throw it away.

[VVTi]

Found some interesting topics on it also, looks like we are not the only ones with the maka baas issue.

Coolant & Thermostats

By Mick Farmer. Filed under 4wd Driving Info in 2001.
Last updated: October 24, 2002.

In Uganda, like the rest of East Africa, mechanics always remove the engine thermostats when the car first arrives in the country. They call this "tropicalising" the vehicle. And as for coolant, the owner is told, that is only necessary in cold countries - water is good enough.

I recently created a bit of controversy by publishing an article (below) that stated otherwise. I am still defending my argument here as people (including expats) are having difficulty believing an engine needs a thermostat to operate correctly! And that coolant is a necessary rust inhibitor.

Here's the "controversial" article

Every week I see vehicles with either one or both missing. The owner/driver of the vehicle looks at me blankly when I say that they are necessary to maintain the correct running temperature of a vehicle. "But it has been running like this now for ages", they say. "It won't be for much longer", I reply, "and you'll soon have a hefty repair bill to boot". This usually grabs their attention!!

Coolant

Coolant or antifreeze, as it is known in colder climates, is recommended by all vehicle manufacturers. Anyone who has run a vehicle in a cold country knows the importance of antifreeze but why then should we put it in our vehicle in a hot country? The answer is two fold.

Firstly, coolant has a corrosion inhibitor, which does what it says. It prevents the build up of corrosion in the cooling system. I'm sure everyone is aware that if you leave a sheet of steel open to the elements it quickly gets covered with rust. This is exactly what happens to the cooling system of your vehicle if run with water only. Eventually the corrosion will build up until it starts to effect the efficiency of the main parts - i.e. the radiator (replacements cost as much as 1.6 million Ush), the water pump, the thermostat and the hoses.

Secondly, coolant raises the boiling point of the cooling system. Therefore, if part of the system does fail and the engine does start to overheat, less damage will occur as fluid loss by vapour evaporation is kept to a minimum.

Thermostats

On then to thermostats. Too often I hear people and so called mechanics saying that thermostats aren't necessary in a hot climate. A thermostat controls the internal temperature of the engine and keeps that temperature constant. Most engines are designed to run at a temperature of 80 degrees Celsius and above.

I would like any one to name me a country that has a temperature that high!! If you run without a thermostat then parts of the engine will run too cool and this can cause accelerated wear. Also, the engine as a whole, will be running at uneven temperatures and therefore, is susceptible to failures. Especially if the engine is made from dissimilar metals i.e. steel engine block with an aluminium cylinder head. If your thermostat becomes faulty by all means take it out, but make sure another correct one is put in its place.

So, if you're unsure get it checked and put right. In the long run it will be cheaper and more reliable!! Safe and happy motoring.

[VVTi]

Why replace your thermostat?

The thermostat has two important jobs to perform: to accelerate engine warm-up and to regulate the engine's operating temperature. A quality thermostat ensures excellent fuel economy, reduces engine wear, diminishes emissions, improves cold weather drivability, provides adequate heater output to keep you warm and comfortable while driving and detours engine overheating. This is accomplished by blocking the circulation of coolant between the engine and radiator until the engine has reached its predetermined temperature.

The thermostat then opens as required in response to changes in coolant temperature to keep the engine's temperature within the desired operating range. Thermostats have a rated temperature such as 180°F or 195°F depending on make and model. This is the temperature the thermostat will start to open, give or take 3 degrees.

The temperature rating specified by the car manufacturer is especially important in many 1981 and newer vehicles because the onboard computer monitors coolant temperature through a coolant sensor to control fuel enrichment, spark timing and operation of the EGR valve. Even on vehicles without computers, thermal vacuum switches that react to a specific coolant temperature are often used to open and close various vacuum circuits that regulate fuel enrichment, timing and EGR. If a colder thermostat is installed, the coolant may never get hot enough to trigger the appropriate control functions or to allow a computer system to go into “closed loop”. Too hot a thermostat can also interfere with the proper operation of engine controls, and increase the engine’s operating temperature to the point where it may experience detonation (spark knock).

http://www.honestjohn.co.uk/forum/post/index.htm?t=9888

Edited February 23, 2014 by VVTi

[Rumesh88]

+1 to VVTi and hence, the corollary "if your mechanic suggests to do away with the thermostat for whatever the reason, he is a makabaas".

[NRX]

Guys! couldn't you identify if something is wrong with the thermostat by the behavior of the temp gauge ?

[VVTi]

Guys! couldn't you identify if something is wrong with the thermostat by the behavior of the temp gauge ?

The most obvious sign will be overheating. I replaced mine with a higher temp range thermostat and I noticed the gauge ran higher than usual. It was a 82 deg unit. What is needed is a 78 deg unit.

[Crosswind]

I think his question was whether you didnt notice that the thermostat was missing, by looking at the temp gauge? Thats the first thing that came to my mind too....

[VVTi]

I think his question was whether you didnt notice that the thermostat was missing, by looking at the temp gauge? Thats the first thing that came to my mind too....

A missing thermostat will not show much from the gauge... the needle will take its time to creep to the mid way point. And in cold days, it will take a very long time. That will be some indication. And the obvious sign of a car running a rich mixture, like a lot of soot and petrol smell.

[Schiffer]

ooohhhh Magnum..... I TOLD YOU.. Put your damn thermostat back on and stop bragging about your engine not getting heat up

[VVTi]

ooohhhh Magnum..... I TOLD YOU.. Put your damn thermostat back on and stop bragging about your engine not getting heat up

LOL.... He is not alone... a lot of people think a cold engine is a well performing engine.

[Schiffer]

Sadly yes, even my old mechanic(R.I.P) used to forcefully remove the thermostat

its the makabases that lead us to believe its a good thing.

like you siad, a engine should run in a certain level of temperature, not too hot, not too cold

which is one reason why many advice not to over rev the car untill you reach its normal temperature.

and i quote

You see guys, the car engine is just a MACHINE and this MACHINE operates

most efficiently

when it’s running at a certain temperature range. The faster the engine reaches that temperature, the better. Until the car is warmed up, the engine is wearing out much faster than normal because the engine oil provides the best protection against friction between all the moving metal parts when it’s it’s completely warmed up. Until it reaches that state, the engine is wearing out much faster than normal. Turning the engine on and immediately driving lightly warms the car up much faster than idling.

[Komisiripala]

Schiffer and magnum: still a better love story than twilight

[VVTi]

Schiffer and magnum: still a better love story than twilight

Like Miley and Justin...

[harshansenadhir]

another way to find out is, when you do long cruising in a constant speech without much load on the engine, the temp gauge falls down unusually.

all in all, if the thermostat is in, then temp gauge should rise up to middle mark very quickly and stay steady there regardless of the exterior conditions.

[trinity]

During a recent trip to the hills, I noticed a few issues with the Forester. Notably black smoke, fume smell and more than usual fuel burn. Thinking that the drop in temp and the rise in altitude could be a factor I ignored it. Had a nagging feeling that the the engine was running rich, so went on to clear all the possible guilty parties. MAF, MAP, O2 Sensor, filters, etc. Had a diagnostic done and all were fine.

Decided to pop the thermostat housing to see if the thermostat was there... SURPRISE... it wasn't... and there you have it.

The thermostat is a crucial part in an engine. In fact, the life and health of the engine actually depends on it. Why our maka baases remove it is beyond me. Asked Senok if they are carrying the part and was surprised to find out that they don’t since no one buys it!!!! So I bought a similar thermostat and put it in, and things just sorted themselves out. No black smoke, no petrol smell. Nothing and the car actually responds slightly better (Could be the Placebo effect too). Ordered the original 78 degree unit and once it arrives will pop it in.

What I am trying to say here is that, it is crucial that all of you INSIST that the thermostat is ins your cars. Don't let your mechanic or whoever tell you otherwise. The durability of your engine depends on it. The engine needs to run at a certain temperature. removing the thermostat forces the car to run cooler, which is NOT GOOD. If it gets blocked and you overheat, replace it. Don't let anyone throw it away.

Machan

Thank you loads for sharing this information. Until I read you post, i never knew that the (some times) mechanics remove and let the car run without it.

Again, thanks for sharing this with us.

Cheers!

[ferrarif50]

During a recent trip to the hills, I noticed a few issues with the Forester. Notably black smoke, fume smell and more than usual fuel burn. Thinking that the drop in temp and the rise in altitude could be a factor I ignored it. Had a nagging feeling that the the engine was running rich, so went on to clear all the possible guilty parties. MAF, MAP, O2 Sensor, filters, etc. Had a diagnostic done and all were fine.

Decided to pop the thermostat housing to see if the thermostat was there... SURPRISE... it wasn't... and there you have it.

The thermostat is a crucial part in an engine. In fact, the life and health of the engine actually depends on it. Why our maka baases remove it is beyond me. Asked Senok if they are carrying the part and was surprised to find out that they don’t since no one buys it!!!! So I bought a similar thermostat and put it in, and things just sorted themselves out. No black smoke, no petrol smell. Nothing and the car actually responds slightly better (Could be the Placebo effect too). Ordered the original 78 degree unit and once it arrives will pop it in.

What I am trying to say here is that, it is crucial that all of you INSIST that the thermostat is ins your cars. Don't let your mechanic or whoever tell you otherwise. The durability of your engine depends on it. The engine needs to run at a certain temperature. removing the thermostat forces the car to run cooler, which is NOT GOOD. If it gets blocked and you overheat, replace it. Don't let anyone throw it away.

Thanks for the info

What they say is its not required for a hot country like sri lanka! but the old fellow who does most of the stuff in my vehicle advised not to remove

Last time, I got the last and only matching thermostat that Toyota Lanka had at the time.

[Sampath Gunasekera]

Hmmm, I remember Thermostat was there when we imported our Trad Sunny in 1989 and, one of Makabass removed it by saying "Lankawata owa wedak nehe mahaththaya".

Edited February 24, 2014 by Sampath Gunasekera

[maheshw]

so my memory goes back for few years when we had Dx Ke72 i was around 15-16 years that time. it started to heat & dad gave it to our usual mechanic. he sorted it & we went a trip to dambulla. even we ran around 70/80km temp gauge was very low. I can remember I touched the engine & said to dad wade hariyatama karala wage .

all that means dat maka bass had remove our thermostat. in our trad sunny also we faced same situation. one of the previous user has removed the thermostat.

as I was not aware on all these things those days we didn’t noticed importance of thermostat.

but on my last buy ek3 I specially checked the thermostat functions after reading few posts.

just my experience

thanks for sharing VVTi

Edited February 24, 2014 by maheshw

[Charith H Jayasinghe]

Thanks for the info....

Recently I did a scan ( I did it for something else) and got two report with 4 min apart. In first one coolant temp was 74'c and second 81'c. Is this alarming something? usually my temp gauge come to middle and stay there without change

[maheshw]

Well... it's just a 7' gap . nothing to worry ne?

[VVTi]

Thats quite normal. The temp is maintained at an approximate level above the thermostat trigger point. In the forester engine its 78C. If your cooling system is fine and your coolant quality is high the temps will go higher without any issues. Cars boil only if there is a leak or some other issue is present.

Edited February 26, 2014 by VVTi

[VVTi]

Since I posted last, picked up an original Thermostat and gasket from Singapore and spent the morning putting them in.

90 minutes since the job started and all done, including a 10km test run to test for leaks...

First indication the job is successful? Temp gauge takes very little time to come to the mid point and stays there. Next indication, No soot on the tail pipe (which was wiped clean prior to test run). Which means ECU is now reading the coolant temp (above 78 deg C)and is happy that the engine is not running cold and has adjusted the fuel curve for optimum spark and timing. ie not running rich anymore.

Total cost... 6500 for the thermostat and gasket, 1100 for coolant (Wurth) and FOC 8 litres of distilled water, courtesy of a friendly battery shop.

Peace of mind... priceless.

Edited March 1, 2014 by VVTi

[Charith H Jayasinghe]

Good job boss

[trinity]

Hi

After reading this thread, i also doubted that my car also running without the thermostat. The reasons are,

1. Temp gauge takes very long time to come to the midpoint. (It stays at quarter point even after running in heavy traffic for about 30 minutes)

2. Recently i observed a strong petrol smell coming from the car

3. Very low fuel consumption

Since these symptoms matches with what VVTi explained, i decided to check whether the thermostat is still there. So yesterday went to Unit#d Mot#rs workshop at Hyde Park since it was near my office and told them to check it.

Their first question was "are you experiencing an overheating issue"?, then they removed the radiator hose and found that the thermostat is still there. The mechanic who removed it and his supervisor told me that the thermostat is broken and the valve stays open all the time and that is the reason for engine takes a long time to come to the working temp.

But surprisingly their suggestion was to run without the thermostat which is contradictory to their findings. I mean if the open valve make it hard to engine to get warm, without a valve it should be very difficult rite. This made me suspect their conclusion about thermostat being broken. So decided to keep the valve with me to get a second opinion and asked them to fix the hose without it.

Also i enquired the price and availability of the part. Its 7500 and they have it at the moment.

What i wanna know is that, is there any way which we can check whether the thermostat is functioning properly.

One other thing i observed while running without the thermostat is that even after driving about an hour in the heavy traffic, temp gauge constantly kept at quarter point. But with the thermostat fixed, it usually came near the midpoint in a drive like this.

Would love to have your thoughts on this guys

Many thanks

[Rumesh88]

Hi

After reading this thread, i also doubted that my car also running without the thermostat. The reasons are,

1. Temp gauge takes very long time to come to the midpoint. (It stays at quarter point even after running in heavy traffic for about 30 minutes)

2. Recently i observed a strong petrol smell coming from the car

3. Very low fuel consumption

Since these symptoms matches with what VVTi explained, i decided to check whether the thermostat is still there. So yesterday went to Unit#d Mot#rs workshop at Hyde Park since it was near my office and told them to check it.

Their first question was "are you experiencing an overheating issue"?, then they removed the radiator hose and found that the thermostat is still there. The mechanic who removed it and his supervisor told me that the thermostat is broken and the valve stays open all the time and that is the reason for engine takes a long time to come to the working temp.

But surprisingly their suggestion was to run without the thermostat which is contradictory to their findings. I mean if the open valve make it hard to engine to get warm without a valve it should be very difficult rite. This made me suspect their conclusion about thermostat being broken. So decided to keep the valve with me to get a second opinion and asked them to fix the hose without it.

Also i enquired the price and availability of the part. Its 7500 and they have it at the moment.

What i wanna know is that, is there any way which we can check whether the thermostat is functioning properly.

One other thing i observed while running without the thermostat is that even after driving about an hour in the heavy traffic, temp gauge constantly kept at quarter point. But with the thermostat fixed, it usually came near the midpoint in a drive like this.

Would love to have your thoughts on this guys

Many thanks

I just can't believe the above explanation coming from a place like U***O. Now that you have the gadget in hand see if the water path is open. Then drop it into a jug filled with boiling water and observe the valve opening slowly. If you have a thermometer you can measure the temperature and see if begins to open at around 50C and fully open when the temperature gets to around 70 - 80C (these figures may vary depending on the thermostat model). For an animation go to

Edited March 5, 2014 by Rumesh88