Lifting Your Vechicle Bonnet To Keep The Engine Cooler

[WarpSpeed]

What if you were to run into something? Instant guillotine. You might end up head less.

Plus like someone said now you get all the engine fumes being sucked into the engine compartment.

It was designed to be closed for a reason, leave it alone.

The vents in front of the windshield allow fresh air into the passenger compartment. Opening the hood (you Brits call a bonnet) allows engine fumes to escape upwards and could be sucked into the passenger compartment. On a long drive over time there exists the possibility of carbon monoxide entering the passenger compartment.:jap:

There is also the option (in most cars) to alter the incoming air to recirculating.

Yes, providing EVERY other opening is also sealed, it doesn't take much gas into a closed car to cause serious illness, JFYI CO is not easily expelled from the body either and builds up over time..

[BSJ]

It's funny how someone spends time thinking of obscur, and pointless, ways to destroy the aerodymanic flow around the body work and reduce the efficiency of both the vehicle and the air-con. So I am not the only one, ay!

[Cuban]

My two Satang's worth:

If you place your hand there and feel hot air passing then it is working.

When the car is in motion, the raised bonnet near the wind-shield will create an area of low pressure and draw the air from the engine bay over the engine thus producing cooling, with the open space below the engine the air will rush pass from the grill but not not circulate over the top of the engine.

I would have to see measurements to see if it has any effect, but it would not hurt.

As for the car makers, I think their priority will be the looks, sleek lines and cost. Compare the family saloons pictured to the supercars that promote their "go-faster" air scoops.

[MoonRiverOasis]

The only parts in a properly designed water cooled engine that require airflow for cooling are the radiators.

Additional air cooling that's not properly engineered and modelled could be detrimental - i.e. the alloy heads could cool too much, increasing oil viscosity and perhaps even creating other problems due to different expansion/contraction rates of the head, gaskets and block.

[undercover]

The reason why the bonnet (hood) is sealed along the plenum line (back edge) is that if you shit an engine coolant and possibly oil is not spewed onto the windscreen, it's all about safety.

......................

Yes I believe this to be the main reason, along with smooth looks, fashion in 2011 is nothing to do with vents, as trends revolve no doubt vents will return along with flared trousers and platform shoes but until that time a slight bonnet lift with a few washers under the bracket is your only option if you feel the need for more airflow through your radiator.

Having raised the rear of the bonnet on many cars and trucks in the past and finding that the aircon worked so much better it was natural that I raised the bonnet on the 2009 Honda Jazz I'm driving at the moment. with a thermometer on the aircon outlet I now have a temperature of 7.1d entering the car where before the bonnet lift I had a temperature of 12.3

Also while parked the heat raising out of the slight gap at the rear of the bonnet is heat that would normally be trapped in.

Im not suggesting everyone rush out and lift the rear of the bonnet or hood what ever you call it. but if you feel your aircon could be cooler then a slight lift of the bonnet is a cheap option.

[wandrinstar]

Like the O.P. Sketch, hes an Interior Designer for Ford,or the Stylist for the Honda Freddy.

[transam]

The reason why the bonnet (hood) is sealed along the plenum line (back edge) is that if you shit an engine coolant and possibly oil is not spewed onto the windscreen, it's all about safety.

......................

Yes I believe this to be the main reason, along with smooth looks, fashion in 2011 is nothing to do with vents, as trends revolve no doubt vents will return along with flared trousers and platform shoes but until that time a slight bonnet lift with a few washers under the bracket is your only option if you feel the need for more airflow through your radiator.

Having raised the rear of the bonnet on many cars and trucks in the past and finding that the aircon worked so much better it was natural that I raised the bonnet on the 2009 Honda Jazz I'm driving at the moment. with a thermometer on the aircon outlet I now have a temperature of 7.1d entering the car where before the bonnet lift I had a temperature of 12.3

Also while parked the heat raising out of the slight gap at the rear of the bonnet is heat that would normally be trapped in.

Im not suggesting everyone rush out and lift the rear of the bonnet or hood what ever you call it. but if you feel your aircon could be cooler then a slight lift of the bonnet is a cheap option.

Tend to agree. l had big probs in traffic with trapped heat, with the rear rubber removed and the car stationery, the gust of hot air being forced out by the fan onto the screen was amazing.

[MoonRiverOasis]

Like the O.P. Sketch, hes an Interior Designer for Ford,or the Stylist for the Honda Freddy.

My best guess would be a Thairung designer..

[wandrinstar]

Like the O.P. Sketch, hes an Interior Designer for Ford,or the Stylist for the Honda Freddy.

My best guess would be a Thairung designer..

Is that a Joke, take aLook at Bob The Builder on U.Tube, they would fit in nicely. I did see one of their trucks and it wasnt that bad it looked like the old Benz G waggon.

[MoonRiverOasis]

Is that a Joke, take aLook at Bob The Builder on U.Tube, they would fit in nicely. I did see one of their trucks and it wasnt that bad it looked like the old Benz G waggon.

No joke - it's the civilian version of Thairung's minaturized VIGO-based Hummer alternative (the MUV-4), so I guess that means it's the Thairung version of a Fortuner for real men - it even has the same dash as a Fortuner LOL

http://www.thairung.co.th/TRModels_Transformer.php

[katabeachbum]

Is that a Joke, take aLook at Bob The Builder on U.Tube, they would fit in nicely. I did see one of their trucks and it wasnt that bad it looked like the old Benz G waggon.

No joke - it's the civilian version of Thairung's minaturized VIGO-based Hummer alternative (the MUV-4), so I guess that means it's the Thairung version of a Fortuner for real men - it even has the same dash as a Fortuner LOL

http://www.thairung....Transformer.php

H4/Benz Gwagen. Used to have 3 Gwagen mid 80s and this is just so retro cool. couldnt find any prices, any idea?

[tommet]

Another of these silly Thai fashions is to "cool" down the engine bey running it several minutes after the stop. This is not necessary if there is no warning sign or the engine temperature is in the red zone.

Not only not necessary, but potentially damaging.. When stopping you want you engine to retain as mcuh heat as possible, so the upon next start the oil is a lower viscosity and starts lubricating sooner..

The only exeption is heavily modified turbo engines, where it's important to keep pumping oil through the bearings until temps are lowered below levels that would cook stationary oil, but that's a very rare car..

The current Vigo 3.0 deisel manual mentions the potential for heat damage to the turbo if you switch the oil circulation off while it is very hot. They have a small panel of "cool down" guidelines, which iirc are between nothing in most conditions, to between 20 seconds and one minute if you have just been speeding your heavily laden truck uphill for a long time.

So I think there is a case for letting the engine cool down at idle for just a minute if you have been going for a few hours at 160 on the motorway on a 38 degree Thai day and quickly stop into a gas station, for example.

Edited July 13, 2011 by tommet

[transam]

Another of these silly Thai fashions is to "cool" down the engine bey running it several minutes after the stop. This is not necessary if there is no warning sign or the engine temperature is in the red zone.

Not only not necessary, but potentially damaging.. When stopping you want you engine to retain as mcuh heat as possible, so the upon next start the oil is a lower viscosity and starts lubricating sooner..

The only exeption is heavily modified turbo engines, where it's important to keep pumping oil through the bearings until temps are lowered below levels that would cook stationary oil, but that's a very rare car..

The current Vigo 3.0 deisel manual mentions the potential for heat damage to the turbo if you switch the oil circulation off while it is very hot. They have a small panel of "cool down" guidelines, which iirc are between nothing in most conditions, to between 20 seconds and one minute if you have just been speeding your heavily laden truck uphill for a long time.

So I think there is a case for letting the engine cool down at idle for just a minute if you have been going for a few hours at 160 on the motorway on a 38 degree Thai day and quickly stop into a gas station, for example.

Synthetic oil.

[katabeachbum]

Another of these silly Thai fashions is to "cool" down the engine bey running it several minutes after the stop. This is not necessary if there is no warning sign or the engine temperature is in the red zone.

Not only not necessary, but potentially damaging.. When stopping you want you engine to retain as mcuh heat as possible, so the upon next start the oil is a lower viscosity and starts lubricating sooner..

The only exeption is heavily modified turbo engines, where it's important to keep pumping oil through the bearings until temps are lowered below levels that would cook stationary oil, but that's a very rare car..

The current Vigo 3.0 deisel manual mentions the potential for heat damage to the turbo if you switch the oil circulation off while it is very hot. They have a small panel of "cool down" guidelines, which iirc are between nothing in most conditions, to between 20 seconds and one minute if you have just been speeding your heavily laden truck uphill for a long time.

all turbo engines, IOW all modern diesels, need a cool down period.

Ordinary driving this is achieved by going max 1500rpm last 5 minutes before parking and stop engine, like in a parking lot or in home neighborhood

On 160kmh highwaydriving, and then pull over for 7/11/ fuel/ toilet/KFC, I never stop engine before cooldown at least 10 minutes, usually I keep it running for the full 20 minutes stop.

Even superb quality synthetic oil has its temp limit, and this limit is reached after stopping engine due to no circulation of oil in turbo. The turbo holds very little oil and is extremely hot. Circulation is needed. As long as you follow makers/dealers service, lower quality oil is used which has a lower temp limit

Without cooldown, turbos lifetime is 100k km as makers warranty. Proper cooldown, 4-500k km is no problem

and lifting the bonnet is no point, its the turbos internals needing cooling, by circulating oil

[tommet]

Synthetic oil.

Anything recommended?

[MoonRiverOasis]

Is that a Joke, take aLook at Bob The Builder on U.Tube, they would fit in nicely. I did see one of their trucks and it wasnt that bad it looked like the old Benz G waggon.

No joke - it's the civilian version of Thairung's minaturized VIGO-based Hummer alternative (the MUV-4), so I guess that means it's the Thairung version of a Fortuner for real men - it even has the same dash as a Fortuner LOL

http://www.thairung....Transformer.php

H4/Benz Gwagen. Used to have 3 Gwagen mid 80s and this is just so retro cool. couldnt find any prices, any idea?

2.5L version is 1.29M, 3.0L version is 1.37M Baht, both 5MT.

Back at the March motor show it had a steady stream of interest, and I have to admit it did have a certain retro cool factor about it... You would have to learn to give it a lot of leeway though - there's more than a few places where things are just a little too utilitarian for me

EDIT: Better Video

Edited July 13, 2011 by MoonRiverOasis

[wandrinstar]

Damned if i can remember what it was.but i had a turbo that stoped when it was ready.You took the Key out, Centrall locked it,and it ran on its own till the temp was O.K..Perhaps a Yank Ford. , i cant remember.but it annoyed me.

[Spoonman]

Damned if i can remember what it was.but i had a turbo that stoped when it was ready.You took the Key out, Centrall locked it,and it ran on its own till the temp was O.K..Perhaps a Yank Ford. , i cant remember.but it annoyed me.

It's called a turbo timer.

[Gary A]

Fumes? What fumes? How would the air passing through the radiator have fumes. Of course an opening at the back of the bonnet will help cool the engine. The question is why would that be necessary? The cooling systems on modern cars rarely suffer any overheating. If your vehicle overheats, you need to flush the system and refill with a decent coolant. The air conditioning condenser is located in front of the radiator and more air passing through will only help the cooling capacity.

If there are fumes coming off the engine, then the engine has a problem and desperately needs repaired. More air circulation would only help that condition. If you have a manifold exhaust leak, I can assure you that you would hear it.

[transam]

Synthetic oil.

Anything recommended?

Your manufacturer will have there own synthetic oil. Nothing better for engine wear/heat protection.

[wandrinstar]

Damned if i can remember what it was.but i had a turbo that stoped when it was ready.You took the Key out, Centrall locked it,and it ran on its own till the temp was O.K..Perhaps a Yank Ford. , i cant remember.but it annoyed me.

It's called a turbo timer.

I didnt think it was an Egg Timer, but dont they have them anymore, or is the Cooling System now so efficient they rarely kick in.?.

[katabeachbum]

Damned if i can remember what it was.but i had a turbo that stoped when it was ready.You took the Key out, Centrall locked it,and it ran on its own till the temp was O.K..Perhaps a Yank Ford. , i cant remember.but it annoyed me.

It's called a turbo timer.

I didnt think it was an Egg Timer, but dont they have them anymore, or is the Cooling System now so efficient they rarely kick in.?.

Porsche 944T had a pump on timer circulating a few minutes after engine stopped

BMW 2002Turbo and Saab Turbo did not mid 70s early 80s, neither did BMW 745i. Plenty of cooked turbos at that time

Oil has become better, turbos have become better, dieselturbos arent that hot and some users have learned

It s unthinkable for a Caterpillar operator to run engine at 80% for a few hours, and then just shut off

[WarpSpeed]

Fumes? What fumes? How would the air passing through the radiator have fumes. Of course an opening at the back of the bonnet will help cool the engine. The question is why would that be necessary? The cooling systems on modern cars rarely suffer any overheating. If your vehicle overheats, you need to flush the system and refill with a decent coolant. The air conditioning condenser is located in front of the radiator and more air passing through will only help the cooling capacity.

If there are fumes coming off the engine, then the engine has a problem and desperately needs repaired. More air circulation would only help that condition. If you have a manifold exhaust leak, I can assure you that you would hear it.

Another person who has 0 understanding of vehicular aerodynamics (high and low pressure zones and how the air flows within them) not to mention that it is extraordinarily seldom (read never) when you are the only one sitting in traffic (hence the description of "traffic") and the vehicles all around you are NOT expelling exhaust which is then brought into your engine compartment by your own cooling system which is closer and down lower to the cars exhaust around you then your windshield is ..And even with all of that it's still based on presumptions that all cars are in perfectly sealed condition which is a huge ass/u/mption not worthy of testing with ones life or someone else's just for a presumed, albeit unnecessary, modification to ones car for a perceived cooler engine compartment..

Edited July 14, 2011 by WarpSpeed

[kartman]

Brilliant thread about hot air .

[Gary A]

Brilliant thread about hot air .

Yes indeed, we do have our hot air experts.

[wandrinstar]

Brilliant thread about hot air .

Yes indeed, we do have our hot air experts.

I just light a Cigarette,open the Window,turn up the Aicon. and inhale all those luvley Engine Fumes, and foreget about Experts.