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

ecosport rules · 27th March 2016, 18:45

There is absolutely no need to keep the engine hood open after a long ride.
The ECU takes care of the temperature control

a4anurag · 27th March 2016, 20:06

All of the modern engines now are intelligent enough to keep themselves cool enough and to prevent temperature increase beyond the safer limits after a long drive. Even then if one feels the need to keep the hood popped up during a break, no harm in doing so.

It has its advantages - faster cooling off/heat dissipation due to larger surface area that is exposed to the atmosphere rather than only the heat escaping from the front slats/air dam.

The last I remember when we had to do this after a long drive was during the Ambassador days but after that never was this needed.

Scarlet_Rider · 28th March 2016, 01:35

Back in the 80s and early 90s, we did many long trips (500+ kms) in our 1961 Fiat 1100 Super Select and the 1957 Fiat 1100 Elegant. Later on in the 90s it was the Premier 118 NE and few years back the PPL Viceroy. We never opened the hood on any of these cars after long drives. Most of these trips were during summer. During long drives, the only time we opened the hood was at the start of the day to check for oil and coolant levels!

Tanveer_2558 · 28th March 2016, 02:52

I don't think modern car's need this to be done, And i think like this only because i have done several trips with 700+ kms with the engine always running, And i never had a issue, Not with the current or the previous car's i have owned.

Yes i do remember my dad doing this in our M800 when i was a small small kid, Well i remember because of a picture clicked at that time, It was during the climb on lonavala.

sandeepmohan · 28th March 2016, 11:17

Quote:

Originally Posted by GTO

Seriously overkill, buddy. You are wasting your time by doing this.

I will agree on the over kill part. Am I wasting time by doing this? Not really. After all, how long does it take to pop the hood. If time it to be factored, well I do have the time. Not everyone may have this luxury.

I will also admit that I am over protective of the car's mechanicals cause I drive a brand of car that has poor support. Maybe this practise saves something or pro longs the life of a certain component. Only time will tell.

However; a comment by FM bblost on whether the spring can survive this practise is valid, cause it may not be designed as sturdy as the boot lock.

LoneRidder · 28th March 2016, 11:24

Do we need to keep the hood up to cool the engine after a long drive?
Definitely no, modern (even the old) cars are built to handle that heat. I have driven my WagonR, with just one break 700 km many times, and the car has performed with heads-up! I even remember, we driving 250 km non-stop with our old MM 540 without any concern.

But does keeping the hood open help?
Definitely it yes! Though the engine is built to handle the amount of heat it generates through radiators etc, keeping the hood open “in-between” long drives helps in dispersing the transferred heat from the engine to various parts and the body of the vehicle. It could help for better AC performance and upkeep of your engine bay plastic parts.

However, keeping your radiators, coolants at perfect is a must. Once we were travelling from Bangalore to Coimbatore in wagonR, we had just reached Coimbatore non-stop (350km) and to my horror, at a signal point smoke gushes out from the hood, the temperature needle slowly started increasing, as the signal light turned green, I move the car out to a by lane and the car stopped! For a Maruti car, it knew where to stop, it had stopped exactly in front of an Authorized Service Center!

The culprit was the coolant! The previous day, before the start of the journey I had given the vehicle for a quick wash to a Bosch service center, the sales guy hoodwinked me for a ‘long trip check-up’ and the mechanic with extra over enthusiasm, had filled the coolant to the brim! I ended up spending 13k.

On returning when I asked the Bosch trainee mechanic, he says, ‘sir you come here often, so I filled the coolant full so that you would be happy

sudev · 28th March 2016, 12:12

Counter intuitive. When you open the hood while engine radiation seems to be getting a vent the flow through radiator core is actually disrupted. Coolant circulation takes away maximum heat rather than radiation and air cooling.

a4anurag · 28th March 2016, 12:37

Quote:

Originally Posted by sudev

Counter intuitive. When you open the hood while engine radiation seems to be getting a vent the flow through radiator core is actually disrupted. Coolant circulation takes away maximum heat rather than radiation and air cooling.

Agree that the coolant does most of the job of heat dissipation but when the car is stationary, how would the cooling be efficient enough as it is when the car is running? Air isn't passing through the radiator to take off the heat, right? Also the engine is kept off so the radiator functionality too is gone.

If the hood is open at least air flow over the hood area would take away some of the heat if not as efficiently as cooling through the radiator process.

sgiitk · 28th March 2016, 15:33

This used to be the norm about thirty years ago. Esp when climbing hills cars would stop, open hood, and cool the radiators. Of course once you were above 1000m or so this was no longer needed - lower volumetric efficiency of engine, and cooler environment. Of course they seldom had functional pressurized radiators, these were choked with rust (no coolant), etc. Used to be common with the Amby and occasionally with Fiat.

sibitg · 29th March 2016, 00:46

From the above replies, I understand that we need not open the hood to cool the engine. But it is better to wait for the radiator fan to turn off before switching off the ignition.

nkghai · 29th March 2016, 08:35

Quote:

Originally Posted by sibitg

From the above replies, I understand that we need not open the hood to cool the engine.

Yup. That's established.

On the contrary, on a lighter note, seeing the road rage incidents, its the occupants who need to keep their heads cool with their minds open rather than the car engine.

Ashokkp · 29th March 2016, 09:57

Hi

I have done 600kms with meal stops in dead of summer at highway speeds in my 10 year old Octavia. The temperature gauge didn't move a bit to the right. The takeaway, no need to open the bonnet to cool as long as the temp. gauge shows normal reading.

Cheers

ramzsys · 29th March 2016, 10:17

Quote:

Originally Posted by Ashokkp

The temperature gauge didn't move a bit to the right. The takeaway, no need to open the bonnet to cool as long as the temp. gauge shows normal reading.

Cheers

Agreed. But the gauge is programmed to sit at the same spot for a certain range of temperatures.

In the fiesta classic, it stays at the same spot for 84-104C.

Ashokkp · 29th March 2016, 10:35

Hello

The manual says the normal temperature is when the gauge is at the half mark. However,I have no idea of the range it represents. As long as its at half mark, consider it normal.

Cheers

Jeroen · 29th March 2016, 12:02

In all of my years driving all sorts of car and all sorts of terrains and environment I've only found myself once in a situation where we opened the hood to cool the engine.

It happened about 15 years ago. I was somewhere in Italy as part of our yearly European tour of the Dutch Alfa Romeo Spider Register. We took some 20 classic Spiders back to their home country, visited the Alfa Romeo museum, the factory etc.

My friend Peter and me are the technical committee so we try and solve all the technical problems enroute. One day during these trip we typically keep as a free day. So nothing is organised, people can spend the whole day lounging in the Hotel pool, walk around or take a trip by themselves.

On the free day, Peter and I always go out for a huge trip through as much rural little roads as we can possibly find. This time we got ourselves into a bit of a problem We ended up on a very steep, very rocky mountain road. Most people wouldn't even attempt to drive up in a 4x4, but we thought it would be good fun to take our Spiders up there, take some pictures of our Spiders on these might rocks, rolling through the river etc.

But it was also unbelievable hot and the going was very slow, very endless manoeuvring around all these huge rocks and what have you in the blazing Italian sun. Both our Spiders started overheating and in order to cool them down we had to kill the engine and open the hoods. We had to do this 5-6 times as it took us several hours to get back on a normal road.

No matter how hard I have pushed other cars, in very hot climates as well, never happened to me again. I think it was just a combination of very slow driving (no air), very high ambient temperature and the engines having to work really hard for prolonged periods,

Also, these classic Spider did not have an electric fan, only belt driven fan.

As long as your temperature gauge doesnt go of the scale I see no reason why I would open the hood to cool the engine

Jeroen

27th March 2016, 18:45	#61
ecosport rules Senior - BHPian Join Date: Jun 2013 Location: Hyderabad Posts: 1,174 Thanked: 2,044 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? There is absolutely no need to keep the engine hood open after a long ride. The ECU takes care of the temperature control
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27th March 2016, 20:06	#62
a4anurag BANNED Join Date: Oct 2011 Location: Hyderabad Posts: 12,350 Thanked: 21,411 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? All of the modern engines now are intelligent enough to keep themselves cool enough and to prevent temperature increase beyond the safer limits after a long drive. Even then if one feels the need to keep the hood popped up during a break, no harm in doing so. It has its advantages - faster cooling off/heat dissipation due to larger surface area that is exposed to the atmosphere rather than only the heat escaping from the front slats/air dam. The last I remember when we had to do this after a long drive was during the Ambassador days but after that never was this needed.
	(1) Thanks

28th March 2016, 01:35	#63
Scarlet_Rider BHPian Join Date: Sep 2010 Location: Hyderabad Posts: 832 Thanked: 1,658 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? Back in the 80s and early 90s, we did many long trips (500+ kms) in our 1961 Fiat 1100 Super Select and the 1957 Fiat 1100 Elegant. Later on in the 90s it was the Premier 118 NE and few years back the PPL Viceroy. We never opened the hood on any of these cars after long drives. Most of these trips were during summer. During long drives, the only time we opened the hood was at the start of the day to check for oil and coolant levels!
	() Thanks

28th March 2016, 02:52	#64
Tanveer_2558 Senior - BHPian Join Date: Apr 2015 Location: Mumbai Posts: 1,701 Thanked: 3,375 Times View My Garage	Re: Do we need to keep the hood up to cool the engine after a long drive? I don't think modern car's need this to be done, And i think like this only because i have done several trips with 700+ kms with the engine always running, And i never had a issue, Not with the current or the previous car's i have owned. Yes i do remember my dad doing this in our M800 when i was a small small kid, Well i remember because of a picture clicked at that time, It was during the climb on lonavala.
	(1) Thanks

28th March 2016, 11:24	#66
LoneRidder BHPian Join Date: Dec 2014 Location: Bangalore Posts: 385 Thanked: 590 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? Do we need to keep the hood up to cool the engine after a long drive? Definitely no, modern (even the old) cars are built to handle that heat. I have driven my WagonR, with just one break 700 km many times, and the car has performed with heads-up! I even remember, we driving 250 km non-stop with our old MM 540 without any concern. But does keeping the hood open help? Definitely it yes! Though the engine is built to handle the amount of heat it generates through radiators etc, keeping the hood open “in-between” long drives helps in dispersing the transferred heat from the engine to various parts and the body of the vehicle. It could help for better AC performance and upkeep of your engine bay plastic parts. However, keeping your radiators, coolants at perfect is a must. Once we were travelling from Bangalore to Coimbatore in wagonR, we had just reached Coimbatore non-stop (350km) and to my horror, at a signal point smoke gushes out from the hood, the temperature needle slowly started increasing, as the signal light turned green, I move the car out to a by lane and the car stopped! For a Maruti car, it knew where to stop, it had stopped exactly in front of an Authorized Service Center! The culprit was the coolant! The previous day, before the start of the journey I had given the vehicle for a quick wash to a Bosch service center, the sales guy hoodwinked me for a ‘long trip check-up’ and the mechanic with extra over enthusiasm, had filled the coolant to the brim! I ended up spending 13k. On returning when I asked the Bosch trainee mechanic, he says, ‘sir you come here often, so I filled the coolant full so that you would be happy Last edited by LoneRidder : 28th March 2016 at 11:27.
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28th March 2016, 12:12	#67
sudev Distinguished - BHPian Join Date: Jan 2008 Location: Gurgaon Posts: 3,838 Thanked: 3,179 Times	Counter intuitive. When you open the hood while engine radiation seems to be getting a vent the flow through radiator core is actually disrupted. Coolant circulation takes away maximum heat rather than radiation and air cooling.
	(1) Thanks

28th March 2016, 15:33	#69
sgiitk BANNED Join Date: Dec 2007 Location: Gurugram Posts: 7,969 Thanked: 4,788 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? This used to be the norm about thirty years ago. Esp when climbing hills cars would stop, open hood, and cool the radiators. Of course once you were above 1000m or so this was no longer needed - lower volumetric efficiency of engine, and cooler environment. Of course they seldom had functional pressurized radiators, these were choked with rust (no coolant), etc. Used to be common with the Amby and occasionally with Fiat.
	() Thanks

29th March 2016, 00:46	#70
sibitg BHPian Join Date: Dec 2015 Location: Bangalore Posts: 82 Thanked: 25 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? From the above replies, I understand that we need not open the hood to cool the engine. But it is better to wait for the radiator fan to turn off before switching off the ignition.
	() Thanks

29th March 2016, 09:57	#72
Ashokkp BHPian Join Date: Apr 2014 Location: Mumbai Posts: 55 Thanked: 19 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? Hi I have done 600kms with meal stops in dead of summer at highway speeds in my 10 year old Octavia. The temperature gauge didn't move a bit to the right. The takeaway, no need to open the bonnet to cool as long as the temp. gauge shows normal reading. Cheers
	(1) Thanks

29th March 2016, 10:35	#74
Ashokkp BHPian Join Date: Apr 2014 Location: Mumbai Posts: 55 Thanked: 19 Times	Re: Do we need to keep the hood up to cool the engine after a long drive? Hello The manual says the normal temperature is when the gauge is at the half mark. However,I have no idea of the range it represents. As long as its at half mark, consider it normal. Cheers
	() Thanks

29th March 2016, 12:02	#75
Jeroen Distinguished - BHPian Join Date: Oct 2012 Location: Delhi Posts: 8,104 Thanked: 50,911 Times View My Garage	Re: Do we need to keep the hood up to cool the engine after a long drive? In all of my years driving all sorts of car and all sorts of terrains and environment I've only found myself once in a situation where we opened the hood to cool the engine. It happened about 15 years ago. I was somewhere in Italy as part of our yearly European tour of the Dutch Alfa Romeo Spider Register. We took some 20 classic Spiders back to their home country, visited the Alfa Romeo museum, the factory etc. My friend Peter and me are the technical committee so we try and solve all the technical problems enroute. One day during these trip we typically keep as a free day. So nothing is organised, people can spend the whole day lounging in the Hotel pool, walk around or take a trip by themselves. On the free day, Peter and I always go out for a huge trip through as much rural little roads as we can possibly find. This time we got ourselves into a bit of a problem We ended up on a very steep, very rocky mountain road. Most people wouldn't even attempt to drive up in a 4x4, but we thought it would be good fun to take our Spiders up there, take some pictures of our Spiders on these might rocks, rolling through the river etc. But it was also unbelievable hot and the going was very slow, very endless manoeuvring around all these huge rocks and what have you in the blazing Italian sun. Both our Spiders started overheating and in order to cool them down we had to kill the engine and open the hoods. We had to do this 5-6 times as it took us several hours to get back on a normal road. No matter how hard I have pushed other cars, in very hot climates as well, never happened to me again. I think it was just a combination of very slow driving (no air), very high ambient temperature and the engines having to work really hard for prolonged periods, Also, these classic Spider did not have an electric fan, only belt driven fan. As long as your temperature gauge doesnt go of the scale I see no reason why I would open the hood to cool the engine Jeroen
	(3) Thanks