[DieselFan]

In my view all modern cars come with good radiators and radiator fans. If both your radiator and the fan is in decent shape there is no need for any stoppage. Ensure that the radiators are cleaned every 40000 kms (It is called Radiator flushing. We add flushing fluid and flush out all the muck gathered in Radiator) and radiator fan is running and you are good to go. People neglect to change radiator fluid or flush radiator and get stuck in the middle of nowhere with overheated engine due to radiator failure. Key is to spend a few rupees on keeping your radiator in top shape so that your engine is taken care of.

[freedom]

If the engine is not seriously overheated due to a malfunction, I see no point in popping the hood.

Its actually better for the engine to cool down slowly. And if you are going to drive after a break, its a 'waste' of energy as the engine will want to warm up again.

[VW2010]

And if you are going to drive after a break, its a 'waste' of energy as the engine will want to warm up again.

May be in colder climates. In India, the engine is warmed up in garage with temperatures already over 35 deg

Only question is if we stop for a break and are idling the car with family sitting inside enjoying the AC, then opening up the hood, will that help as the car is no longer sucking in volumes of cold air to remove heat generated?

This is the only scenario where i feel keeping the hood up probably will help technically as well.

[landcruiser123]

Not necessary. There's a lot of air flow at high speeds, hence the radiator is efficient enough to keep the engine cool. You don't need to open the hood.

Also, do you realise that the ECU can keep the radiator fan running for a few ten seconds after you park?

Originally Posted by smartcat

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.

[sumeethaldankar]

Once while driving home from office my oldie 800 developed a cooling problem. I later on had discovered the radiator fan was not working but at that time of driving it was not known to me that the fan had gone kaput. I noticed the temp guage had risen a bit above normal but since i was driving on a free highway it was not causing much issue and i continued on. Once i reached a traffic area i found the car to be heating up fast. I reached home by stopping for 10 min intervals by keeping the bonnet open at every stop.

I managed to get the car home safely without overheating the engine this way So moral of the story is that you need not keep the hood open to cool the car after a 500 km run as demonstrated by my 800 which ran without a fan on the highway as the flowing air kept the radiator cool enough on the highway run. So unless the car is heating up more than normal which means if the temp guage which should always be lesser than halfway mark you need not keep the hood open after a long run.

[antz.bin]

By the looks of things, these guys are definitely not doing it : https://twitter.com/adiljal/status/7...131823104?s=09

[YaeJay]

25 years back, on a new jeep or car up a steep climb ( 36/36 ) or even smaller climbs around nilgiris that used to be the norm. Those were the days when the coolant was pure water. I have known friends who used to drive down from chennai to nagercoil who used to stop at madurai for lunch and leave the hood open. Maruthi changed everything. even bikes dont heat up on 500 km highway rides. So, I dont think one needs to do that. But parking in shade for lunch on a whole day drive would be a nice thing.

[mustysekhon]

On long drives when I have to stop for an unavoidable meal or coffee break for more than 5 minutes, I drop the family close to the entry door and drive to a shady spot. It's my irrational belief that all parts (rubber, beatings etc) deserve a cool down.

[sandeepmohan]

Forget a highway drive, I pop the hood almost every day when I get back from work. I know it is not required but I still do it. The thought of all that heat trapped in there for several hours is the reason I leave the hood open. I leave it open for half an hour at the most. Off course, I have a covered parking and live in a very small community. My only concern was safety and its been okay so far. We are 12 houses and only 3 car owners. In fact, my apartment guard drops the hood every evening, before he leaves for next duty, at another apartment. On the day I started doing this, I had to explain to him why, post which, he started touching the coolant reservoir to see if it has cooled down.

Every Friday, I leave the hood open longer. After an hour or so, I take my Skill Industrial Blower and blow out all the dust inside the engine bay and from the radiator area. You will be shocked to see the amount of dust that comes out with just one week of driving.

To be honest, all this is a bit too much. A modern day car is designed to handle everything you throw at it . I have the time, so I do it.

[bblost]

@sandeepmohan:

You don't need to do this at all. There is no absolutely no mechanical issue a normal car will face if you let it cool down on its own.

My car's engine bay is cleaned twice a year. When the car goes for service. Normal car wash guys are warned against opening the bonnet.

If anything I am not sure if the spring lock that keeps the bonnet locked is built for this daily wear and tear!!!

[saket77]

Definitely not required unless the temperature gauge shoots up beyond normal. I don't think it was required in older cars as well. We had an 1100D which had seen quite a bit of highways. Apart from filling up the radiator with water, we did not need to open the hood with intention of cooling it faster.
However, I think I have read in my Zen's manual that the car must be given a small rest when driving continuously over 3 or 4 hours. I will try to find that in the manual and post here but still it does not say to keep the hood open for the purpose of cooling. I have done more than 12 hours of almost non stop driving in my Zen, 1100D and even the Civic. None had any problems what so ever. In fact, love the smoothness and the increased engine response once the cars travel long distance at a stretch.

[Durango Dude]

I have owned an Elantra petrol for more than 10 years and have had a look under the hood less than ten times in that time. I don't think modern cars need the hood to be popped, unless you're driving a vintage classic.

[anjan_c2007]

It was necessary for old generation cars and would always be preferable. This was because most unpredictably, sometimes the engine would heat up with either the fan belt or the water pump not doing their jobs. Yes, the temperature gauge if OK would do its job, but it was always preferable to check visually as to whether anything was wrong under the bonnet.

Once while travelling in a brand new Mahindra CJ 4A (Hurricane engine), the rubber washer of the cylindrical engine oil filter had turned spoilsport and engine oil had leaked (splashed) within the engine bay. It was only after halting and opening its bonnet that I came to know of the fault and had got a replacement from the nearest town. About half a litre of oil had leaked. The component quality was so untrustworthy during those days.

During summer, it was common to have engine ignition coils of Fiats, Ambassadors and Jeeps get heated up. It would not move after stalling. And one would have to halt, apply moistened cloth to cover up the coil and cool down the engine and then restart.

For new generation vehicles, though not very essential unless the temperature gauge shows any northward movement, its preferable to open up the bonnet and check up for any gremlins visually.

[SmartCat]

Originally Posted by bblost

If anything I am not sure if the spring lock that keeps the bonnet locked is built for this daily wear and tear!!!

In my case, the bonnet of my car is opened only once a year (when I give the car for servicing). Because of this, I think my bonnet opening mechanism is jammed shut - I'm unable to open it

[auto_enthusiast]

If the cooling systems are working fine, then not just 500 kms, we can go beyond 5,000 kms or 10,000 kms at a stretch.

Case in point being the Live TATA VRDE run. All their cars are running at near top speed for the full service interval of 10,000 kms, except for switching of drivers and for refueling. So for our normal highway and city runs, it's definitely not required