thermostat and overheat

[edtf]

I noticed that different vehicles have different thermostat settings. Like the Isuzu 4jg2 theremostat is rated at 82deg while a Mitsu 4d56 is 79 deg.

Now with this in mind does this make the overheat temp different for both and what temperature is considered as overheat for a diesel engine? 120deg Celsius? Thanks!

[Ry_Tower]

I noticed that different vehicles have different thermostat settings. Like the Isuzu 4jg2 theremostat is rated at 82deg while a Mitsu 4d56 is 79 deg.

Now with this in mind does this make the overheat temp different for both and what temperature is considered as overheat for a diesel engine? 120deg Celsius? Thanks!

It depends upon the design of each engine kasi. Yung nipis ng engine block, yung laki ng holes na dinadaanan ng coolant/water will be a factor. Mas malaki engine block at malalaki holes, mas matagal mag-overheat afaik. Hindi lang Isuzu ganyan, per car manufacturer meron din for sure na different overheat temp depende sa design nga ng engine.

[jick.cejoco]

I noticed that different vehicles have different thermostat settings. Like the Isuzu 4jg2 theremostat is rated at 82deg while a Mitsu 4d56 is 79 deg.

Now with this in mind does this make the overheat temp different for both and what temperature is considered as overheat for a diesel engine? 120deg Celsius? Thanks!

the temperature setting stamped on the thermostat is not the overheat temperature setting. it is merely an approximate temperature at which the thermostat begins to open. the engine operating temperature during optimum operation is between 190 to 240 degrees fahrenheit. bear in mind, that you can not base this on the boiling point of water from sea level up to about 1000 feet above sea level. the coolant solution is a mixture of anti-freeze/anti-boil coolant and water and is subject to as much as 12.8 to 16 psig that raises the boiling point about 3 degrees fahrenheit per psi of pressure increase

[edtf]

the temperature setting stamped on the thermostat is not the overheat temperature setting. it is merely an approximate temperature at which the thermostat begins to open. the engine operating temperature during optimum operation is between 190 to 240 degrees fahrenheit. bear in mind, that you can not base this on the boiling point of water from sea level up to about 1000 feet above sea level. the coolant solution is a mixture of anti-freeze/anti-boil coolant and water and is subject to as much as 12.8 to 16 psig that raises the boiling point about 3 degrees fahrenheit per psi of pressure increase

yup understood I know that temp stamped of thermostat is opening temp of thermostat. So more or less that is optimum operation temp. What is now more or less overheat temp of diesel engines?

Hmmm thanks bro ry_tower but what is the general range of overheat?? around 190-220 deg Celsius??

[jick.cejoco]

yup understood I know that temp stamped of thermostat is opening temp of thermostat. So more or less that is optimum operation temp. What is now more or less overheat temp of diesel engines?

Hmmm thanks bro ry_tower but what is the general range of overheat?? around 190-220 deg Celsius??

by 190-220 celsius the engine might already have locked up. maybe you mean 190-220 fahrenheit sounds like most diesel engines operate at optimum. above the 220 degree fahrenheit mark, nitrogen in the air reacts with combustion creating oxides of nitrogen (air pollutant), the engine oil starts to degenerate, metals tend to expand more than the designed expansion rate (aluminum piston expands more than cast iron engine block) and the engine efficiency declines

[Ry_Tower]

by 190-220 celsius the engine might already have locked up. maybe you mean 190-220 fahrenheit sounds like most diesel engines operate at optimum. above the 220 degree fahrenheit mark, nitrogen in the air reacts with combustion creating oxides of nitrogen (air pollutant), the engine oil starts to degenerate, metals tend to expand more than the designed expansion rate (aluminum piston expands more than cast iron engine block) and the engine efficiency declines

190 fahrenheit is just 87 celsius. Hindi pa nga boiling point ng water eh so i'm sure the engine won't seize in that heat level, even 220 fh is just 107 celsius so ok pa naman. Baka nga 190-220 fahrenheit ang optimum temp ng typical production diesel engine.

[miked]

recall from our basic physics that water boils at 100 deg C at atmospheric pressure of 14.7 psi (101,325 Pa). this is the case when we are not using a rad cap. if we are using a cap, we are increasing the pressure and as a result the boiling temp is also increased. add ethylene glycol (prestone, etc.), you further increase the boiling temp. and as the elevation increases (ex. going to high places like baguio, etc.), the boiling pt of water decreases. so boiling temp is a function of pressure.

meself uses 82 deg C thermostat on a 4d56 turbo (no intercooler). just overheated this monday due to a loose alternator adjuster bolt. temp reach as high as 240 F on the mechanical gage while the stock electric gage is just beginning to rise from the normal range. no abnormal engine sound or vibration present and truck pulls normally when at 240F. engine started right away after the tensioning. to answer sir edtf's question beyond 240F (115C) could mean a blown engine as per my experience. i also experienced running the truck before at 212F (100C) for about 10-20 mins.

me too have a question: why is it that some engines have their thermostat located at the lower hose (suction side) rather than on the upper hose (discharge side)? any explanation? thanks

[jick.cejoco]

recall from our basic physics that water boils at 100 deg C at atmospheric pressure of 14.7 psi (101,325 Pa). this is the case when we are not using a rad cap. if we are using a cap, we are increasing the pressure and as a result the boiling temp is also increased. add ethylene glycol (prestone, etc.), you further increase the boiling temp. and as the elevation increases (ex. going to high places like baguio, etc.), the boiling pt of water decreases. so boiling temp is a function of pressure.

meself uses 82 deg C thermostat on a 4d56 turbo (no intercooler). just overheated this monday due to a loose alternator adjuster bolt. temp reach as high as 240 F on the mechanical gage while the stock electric gage is just beginning to rise from the normal range. no abnormal engine sound or vibration present and truck pulls normally when at 240F. engine started right away after the tensioning. to answer sir edtf's question beyond 240F (115C) could mean a blown engine as per my experience. i also experienced running the truck before at 212F (100C) for about 10-20 mins.

me too have a question: why is it that some engines have their thermostat located at the lower hose (suction side) rather than on the upper hose (discharge side)? any explanation? thanks

there are some liquid cooling systems that are in reverse flow from the traditional. an example is a late model chevrolet corvette, by doing so, the temperature is somewhat more stable when the thermostat opens and closes. this gave an additional of about 7 free horsepower than when the flow of coolant was not reversed

[miked]

traditional coolant flow would be from the lower tank-engine water pump-water jacket-then out the upper discharge hose???what's the traditional flow?

[vhim]

mga sir good day sa inyo bago ako sa tsikot same problem ko rin sa toyota lucida ko overheating baka pwede makahingi ng advice or explain bakit po nag ooverheat ang toyota 3c t engine ko...thanks