Do we need to keep the hood up to cool the engine after a long drive?

sibitg · 24th March 2016, 11:29

Do we need to keep the hood open after a 500KM drive? Does this help the engine to cool off after a long drive? Or is this not required for modern engines?

bblost · 24th March 2016, 11:33

Never ever done this on either my old wagon r or my current sail.

Both have routinely been driven non stop for over eight hundred kilometres.

By non stop I mean non stop with only halt being for fuel at 450 kms.

Desmosedici · 24th March 2016, 11:33

Quote:

Originally Posted by sibitg

Do we need to keep the hood open after a 500KM drive? Does this help the engine to cool off after a long drive? Or is this not required for modern engines?

As long as your temperature gauge shows the usual expected level i don't think its required. I have done several trips of 500kms and have never done anything like this. Never had to in fact.

Cheers,
Raj

MDED · 24th March 2016, 11:52

Quote:

Originally Posted by sibitg

Do we need to keep the hood open after a 500KM drive? Does this help the engine to cool off after a long drive? Or is this not required for modern engines?

Opening of hood was required to be done for old generation engines wherein the heat levels were uncontrollable. Over a period of time more refined and tuned engines have made their way below the hood and in turn this tedious process fraught with dangers have subsided.
Keeping the hood open under any condition without actual supervision of specialist can lead to complications in the engine owing to any foreign object making way into the engine compartment and thereby brushing the pumps or parts.
As suggested by other bhpian, unless your temperature gauge is reflecting optimum engine temperature, the need of any rocket science is dispensed with.

aaggoswami · 24th March 2016, 11:57

Its not required in modern cars. I have done more than 500 kms. in Gujarat's hot temperature and as long as there isn't anything wrong with the car or unless the temperature gauge indicates higher than normal temperature, never opened hood of any of my cars. This is where I believe that a temperature gauge is an absolute must.
Opening hood after 400-500 kms. drive an old concept similar to high revving engines before shutting them down.

Ravindra M · 24th March 2016, 12:05

No need to keep the hood up to keep the engine cool as such. It reminds me of the bygone era - Ambassadors fitted with Matador engines - which needed it frequently.

As long as the car is being driven, the airflow ensures that the excess heat is dissipated. The engine room temperature settles around 90 deg.C. All parts in the engine room are designed for it.

But when the car is resting after a long drive, the engine room temperature continues to raise in absence of air flow. It may reach as high as 110 deg.C. Although the plastic parts and electrical parts are designed to withstand this much of temperature, I always felt to keep the hood open so that the excess heat is not trapped and plastic parts don't degenerate. This I do it for my modern classic car Mercedes W124, just for the peace of mind. I don't do it for other cars which are more modern.

If you travel long distances very frequently with heavy load and in summer and you have an older car, it is a good idea to do it. But also be aware of other factors like safety and convenience which are more important.

Ajay_the_Don · 24th March 2016, 13:35

The truth is any car engine is relatively cool after a long distance highway run, As there is constant air flow to the radiators. I have covered 800 km in a single day in my safari and have observed the engine temperature to be below normal than what's within city limits.

Do follow the turbo idling http://www.team-bhp.com/tech-stuff/i...o-charged-cars if it's a Diesel.

SmartCat · 24th March 2016, 16:44

Only if you really have to park in a NO PARKING zone for some reason and you are worried about traffic cops giving you a ticket.

fiestarry · 24th March 2016, 16:54

Modern liquid cooled automobiles engines are designed to perform for long hours without a stop.
What you need to keep an eye on is the temperature gauge ( if provided). If it is steady in the same position where it normally settles after about 15 km of drive, then there is no need to worry.
What you could do to help your car is to idle it for a few minutes before shutdown whilst stopping on the highway for a quick bite.
The engine temp goes up a bit because the water pump is no longer able to circulate the coolant. The coolant in the cylinder will be static and heat up a bit. Therefore, a few minutes of idling after racing down the highway is a help.

Gansan · 24th March 2016, 17:22

It is not required. But I sometimes do it if I want to cover my car immediately after returning home. Keeping the hood up for ten minutes dissipates the heat fast, enabling me to cover it quickly.

GTO · 24th March 2016, 17:30

Honestly, I don't think it was required for the older generation cars either. Must be a wise guy who wrongly thought it'll cool his car, and then every other dude followed him (much like the habit of starting the hazard lights in tunnels or the right blinker to say 'overtake me').

As Ajay & Ravindra said, there is ample air flow at highway speeds. My Jeep is an old-school vehicle and I've never had to keep the bonnet open to 'cool her off' either.

sunsetorange · 24th March 2016, 17:35

Quote:

Originally Posted by sibitg

Do we need to keep the hood open after a 500KM drive? Does this help the engine to cool off after a long drive? Or is this not required for modern engines?

When parking the car in the garage after a long drive, I let the engine idle for a minute( turbo being the reason), check all lights and gauges and switch off the engine.

If no one's looking I kiss the steering wheel boss :-)

dhanushs · 24th March 2016, 17:51

Well, if you are so keen on cooling your car, its not after a 500kms long drive. Its after that 2km traffic jam on the way back home.

Seriously, long drives means plenty of air into the engine bay and the engine runs muh cooler. Whereas bumper to bumper traffic is where the cooling system works hard.

In any case, opening the bonnet is not required. Cars are much more evolved nowadays

sudev · 24th March 2016, 17:52

No rational reason to do this unless your car overheats and steam jets ensue. Then also better to let things be at standstill for an hour before opening hood. Potentially avoiding steam burns. Overheating is more likely in city stop and go traffic than constant highway cruise.

VW2010 · 24th March 2016, 17:53

The only equally crazy thing we did on a frozen day in jersey was to pour hot water on an old honda engine to give it some heat. Funnily it worked and we still have a laugh about it.

Exactly opposite to cooling and totally functional. So I would say it will surely help but is it required probably not in modern cars.

24th March 2016, 11:29	#1
sibitg BHPian Join Date: Dec 2015 Location: Bangalore Posts: 82 Thanked: 26 Times	Do we need to keep the hood up to cool the engine after a long drive? Do we need to keep the hood open after a 500KM drive? Does this help the engine to cool off after a long drive? Or is this not required for modern engines?
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24th March 2016, 11:33	#2
bblost Team-BHP Support Join Date: Jul 2007 Location: Hyderabad Posts: 11,286 Thanked: 17,949 Times View My Garage	re: Do we need to keep the hood up to cool the engine after a long drive? Never ever done this on either my old wagon r or my current sail. Both have routinely been driven non stop for over eight hundred kilometres. By non stop I mean non stop with only halt being for fuel at 450 kms.
	(9) Thanks

24th March 2016, 11:57	#5
aaggoswami Senior - BHPian Join Date: May 2007 Location: Vadodara Posts: 4,997 Thanked: 3,000 Times	re: Do we need to keep the hood up to cool the engine after a long drive? Its not required in modern cars. I have done more than 500 kms. in Gujarat's hot temperature and as long as there isn't anything wrong with the car or unless the temperature gauge indicates higher than normal temperature, never opened hood of any of my cars. This is where I believe that a temperature gauge is an absolute must. Opening hood after 400-500 kms. drive an old concept similar to high revving engines before shutting them down. Last edited by aaggoswami : 24th March 2016 at 11:58.
	(4) Thanks

24th March 2016, 12:05	#6
Ravindra M BHPian Join Date: Mar 2009 Location: Bangalore Posts: 289 Thanked: 249 Times	re: Do we need to keep the hood up to cool the engine after a long drive? No need to keep the hood up to keep the engine cool as such. It reminds me of the bygone era - Ambassadors fitted with Matador engines - which needed it frequently. As long as the car is being driven, the airflow ensures that the excess heat is dissipated. The engine room temperature settles around 90 deg.C. All parts in the engine room are designed for it. But when the car is resting after a long drive, the engine room temperature continues to raise in absence of air flow. It may reach as high as 110 deg.C. Although the plastic parts and electrical parts are designed to withstand this much of temperature, I always felt to keep the hood open so that the excess heat is not trapped and plastic parts don't degenerate. This I do it for my modern classic car Mercedes W124, just for the peace of mind. I don't do it for other cars which are more modern. If you travel long distances very frequently with heavy load and in summer and you have an older car, it is a good idea to do it. But also be aware of other factors like safety and convenience which are more important. Last edited by Ravindra M : 24th March 2016 at 12:09. Reason: Revision
	(9) Thanks

24th March 2016, 13:35	#7
Ajay_the_Don BHPian Join Date: Jan 2016 Location: Chennai Posts: 99 Thanked: 200 Times View My Garage	re: Do we need to keep the hood up to cool the engine after a long drive? The truth is any car engine is relatively cool after a long distance highway run, As there is constant air flow to the radiators. I have covered 800 km in a single day in my safari and have observed the engine temperature to be below normal than what's within city limits. Do follow the turbo idling http://www.team-bhp.com/tech-stuff/i...o-charged-cars if it's a Diesel.
	(4) Thanks

24th March 2016, 16:44	#8
SmartCat Team-BHP Support Join Date: Jun 2007 Location: Bangalore Posts: 7,191 Thanked: 51,820 Times View My Garage	re: Do we need to keep the hood up to cool the engine after a long drive? Only if you really have to park in a NO PARKING zone for some reason and you are worried about traffic cops giving you a ticket.
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24th March 2016, 16:54	#9
fiestarry BANNED Join Date: Mar 2012 Location: Mumbai Posts: 341 Thanked: 608 Times	re: Do we need to keep the hood up to cool the engine after a long drive? Modern liquid cooled automobiles engines are designed to perform for long hours without a stop. What you need to keep an eye on is the temperature gauge ( if provided). If it is steady in the same position where it normally settles after about 15 km of drive, then there is no need to worry. What you could do to help your car is to idle it for a few minutes before shutdown whilst stopping on the highway for a quick bite. The engine temp goes up a bit because the water pump is no longer able to circulate the coolant. The coolant in the cylinder will be static and heat up a bit. Therefore, a few minutes of idling after racing down the highway is a help.
	(4) Thanks

24th March 2016, 17:22	#10
Gansan Senior - BHPian Join Date: May 2009 Location: Chennai Posts: 4,625 Thanked: 5,917 Times	re: Do we need to keep the hood up to cool the engine after a long drive? It is not required. But I sometimes do it if I want to cover my car immediately after returning home. Keeping the hood up for ten minutes dissipates the heat fast, enabling me to cover it quickly.
	(2) Thanks

24th March 2016, 17:30	#11
GTO Team-BHP Support Join Date: Feb 2004 Location: Bombay Posts: 71,833 Thanked: 321,561 Times View My Garage	re: Do we need to keep the hood up to cool the engine after a long drive? Honestly, I don't think it was required for the older generation cars either. Must be a wise guy who wrongly thought it'll cool his car, and then every other dude followed him (much like the habit of starting the hazard lights in tunnels or the right blinker to say 'overtake me'). As Ajay & Ravindra said, there is ample air flow at highway speeds. My Jeep is an old-school vehicle and I've never had to keep the bonnet open to 'cool her off' either.
	(15) Thanks

24th March 2016, 17:51	#13
dhanushs Distinguished - BHPian Join Date: Oct 2009 Location: Chennai Posts: 4,433 Thanked: 11,471 Times	re: Do we need to keep the hood up to cool the engine after a long drive? Well, if you are so keen on cooling your car, its not after a 500kms long drive. Its after that 2km traffic jam on the way back home. Seriously, long drives means plenty of air into the engine bay and the engine runs muh cooler. Whereas bumper to bumper traffic is where the cooling system works hard. In any case, opening the bonnet is not required. Cars are much more evolved nowadays
	(19) Thanks

24th March 2016, 17:52	#14
sudev Distinguished - BHPian Join Date: Jan 2008 Location: Gurgaon Posts: 3,863 Thanked: 3,250 Times	No rational reason to do this unless your car overheats and steam jets ensue. Then also better to let things be at standstill for an hour before opening hood. Potentially avoiding steam burns. Overheating is more likely in city stop and go traffic than constant highway cruise.
	(5) Thanks

24th March 2016, 17:53	#15
VW2010 Senior - BHPian Join Date: Dec 2010 Location: electricity Posts: 2,947 Thanked: 4,558 Times	re: Do we need to keep the hood up to cool the engine after a long drive? The only equally crazy thing we did on a frozen day in jersey was to pour hot water on an old honda engine to give it some heat. Funnily it worked and we still have a laugh about it. Exactly opposite to cooling and totally functional. So I would say it will surely help but is it required probably not in modern cars.
	(4) Thanks