How long can a car engine run at idle until it overheats?

jtvang125

Diamond Member
Nov 10, 2004
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Considering the level of gas is monitored and refilled when low, how long can the engine run at idle until it overheats. The only cooling it has is its own cooling system and no air is being blown into the engine compartment. The engine and cooling system is in good running order and the car is placed in a 80 degree environment.
 

fbrdphreak

Lifer
Apr 17, 2004
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Originally posted by: jtvang125
Considering the level of gas is monitored and refilled when low, how long can the engine run at idle until it overheats. The only cooling it has is its own cooling system and no air is being blown into the engine compartment. The engine and cooling system is in good running order and the car is placed in a 80 degree environment.
The only cooling it has is its own cooling system? As in the radiator fans that cool the radiator? :confused: Why wouldn't it run?
 

Biggerhammer

Golden Member
Jan 16, 2003
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Assuming properly functioning systems, it should get to operating temperature and stay there until you run out of gas. (Then, it'll cool down to ambient again ;) )
 

jtvang125

Diamond Member
Nov 10, 2004
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Originally posted by: Armitage
It should run indefinitely.

So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?
 

LordUnum

Golden Member
Jul 3, 2001
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Originally posted by: jtvang125
Originally posted by: Armitage
It should run indefinitely.

So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?
RADFAN FTW! You don't need much airflow at all to keep an idling engine cool.
 

Armitage

Banned
Feb 23, 2001
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Originally posted by: jtvang125
Originally posted by: Armitage
It should run indefinitely.

So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?

The fan is pulling air through the radiator. That's all it needs.
 

Amused

Elite Member
Apr 14, 2001
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All modern water cooled cars have radiator fans. Only air cooled older VWs and V-twin motorcycles will overheat if left idling.

Your car will simply run out of gas if it's in good repair and functioning properly.
 

Zenmervolt

Elite member
Oct 22, 2000
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Originally posted by: jtvang125
Originally posted by: Armitage
It should run indefinitely.
So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?
Only if there are fans to pull air through the radiator. There absolutely must be airflow through the radiator for a car (in very cold weather, some semi trucks may not need this because their cooling systems are massively over-engineered in order to be able to stand pulling several tons through places like AZ in the summer at 80 mph and 130 degrees, but I'm not sure).

The fans in an engine compartment are not to blow air on the engine, they are to pull air through the radiator.

ZV
 

Specop 007

Diamond Member
Jan 31, 2005
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Originally posted by: Zenmervolt
Originally posted by: jtvang125
Originally posted by: Armitage
It should run indefinitely.
So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?
Only if there are fans to pull air through the radiator. There absolutely must be airflow through the radiator for a car (in very cold weather, some semi trucks may not need this because their cooling systems are massively over-engineered in order to be able to stand pulling several tons through places like AZ in the summer at 80 mph and 130 degrees, but I'm not sure).

The fans in an engine compartment are not to blow air on the engine, they are to pull air through the radiator.

ZV

I can attest to not needing it. Our Jetta TDI, hell I could drain the radiator I swear, if its under...ohhh....20 degrees or so. get around 0 and you'll be at your destination before its warmed up. :(
 

JulesMaximus

No Lifer
Jul 3, 2003
74,544
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It should not overheat when running at idle. If it does, there's something wrong with it.

I've sat in a 100 degree parking lot in the sun with the windows up and the A/C blasting for a good 30-40 minutes in my Maxima while my son slept in the back. The gauge never moved up past normal.
 

jtvang125

Diamond Member
Nov 10, 2004
5,399
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Originally posted by: Zenmervolt
Originally posted by: jtvang125
Originally posted by: Armitage
It should run indefinitely.
So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?
Only if there are fans to pull air through the radiator. There absolutely must be airflow through the radiator for a car (in very cold weather, some semi trucks may not need this because their cooling systems are massively over-engineered in order to be able to stand pulling several tons through places like AZ in the summer at 80 mph and 130 degrees, but I'm not sure).

The fans in an engine compartment are not to blow air on the engine, they are to pull air through the radiator.

ZV


Yes, I know the fan is not meant to blow air to the engine but to draw air from the outside and through the radiator to cool the coolant. I just wasn't sure if this was efficient enough to keep the coolant cool for an extended amount of time.
 

Raduque

Lifer
Aug 22, 2004
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Originally posted by: jtvang125
Considering the level of gas is monitored and refilled when low, how long can the engine run at idle until it overheats. The only cooling it has is its own cooling system and no air is being blown into the engine compartment. The engine and cooling system is in good running order and the car is placed in a 80 degree environment.

Sounds like an experiment!

Try it and report back.
 

JulesMaximus

No Lifer
Jul 3, 2003
74,544
924
126
Originally posted by: jtvang125
Originally posted by: Zenmervolt
Originally posted by: jtvang125
Originally posted by: Armitage
It should run indefinitely.
So the cooling system is efficient enough to keep the engine cool even without air moving to the engine?
Only if there are fans to pull air through the radiator. There absolutely must be airflow through the radiator for a car (in very cold weather, some semi trucks may not need this because their cooling systems are massively over-engineered in order to be able to stand pulling several tons through places like AZ in the summer at 80 mph and 130 degrees, but I'm not sure).

The fans in an engine compartment are not to blow air on the engine, they are to pull air through the radiator.

ZV


Yes, I know the fan is not meant to blow air to the engine but to draw air from the outside and through the radiator to cool the coolant. I just wasn't sure if this was efficient enough to keep the coolant cool for an extended amount of time.

A typical internal combustion engine operates at a temperature of between 190 and 200 degrees F and should be able to idle for an extended amount of time without overheating in most conditions. Unless it's a British car of course. :p
 

Vic

Elite Member
Jun 12, 2001
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Originally posted by: Amused
All modern water cooled cars have radiator fans. Only air cooled older VWs and V-twin motorcycles will overheat if left idling.

Your car will simply run out of gas if it's in good repair and functioning properly.
Even an old air-cooled VW should be able to run indefinitely at idle without overheating. There is a cooling fan, located inside the shroud, that is turned by the generator pulley.