Td5 Diesel fuel leak

[QUOTE=Tombie2;1292702]Rubbish! Makes absolutely no temperature difference (tested with laser).
All it does is allows more heat to radiate to the upper firewall.

which by the laws of physics means there is less heat around the head! No way round that one.



Rubbish again :mad: Now the directed airflow through the radiator and cooling system is not being directed properly. In hot climates like over here this will result in the engines cooling system working harder than it should.


double rubbish mate, the undershield is mostly after the radiator, unless air can flow backwards when the car is going forwards, I can't see any way this can disrupt air flow coming in through the front vent.

Its main function is to reduce driveby noise, the subtle clue being in the sound insulation stuff its covered in. :)

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Originally Posted by gerry_Canavan

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Originally Posted by Tombie2

Rubbish! Makes absolutely no temperature difference (tested with laser).
All it does is allows more heat to radiate to the upper firewall.

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which by the laws of physics means there is less heat around the head! No way round that one.



Rubbish again :mad: Now the directed airflow through the radiator and cooling system is not being directed properly. In hot climates like over here this will result in the engines cooling system working harder than it should.


double rubbish mate, the undershield is mostly after the radiator, unless air can flow backwards when the car is going forwards, I can't see any way this can disrupt air flow coming in through the front vent.

Its main function is to reduce driveby noise, the subtle clue being in the sound insulation stuff its covered in. :)

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Physics states heat radiating away results in a cooler temp? Not if the temperature is sustained... Or perhaps a cool spot occurs on the head does it? so the 5th pot is colder than 1 thru 4... Please....

And heres a subtle clue.. None - Not one.. of the TD5 undertrays I have ever removed has this "sound insulation" you refer to. They do however sometimes have a reflective insulation... This is for heat reflection. Considering the tray ends forward of the engine, just below the radiator shroud its purposes besides airflow will only serve to prevent water splashing up from below into the fan (kind of handy feature in a 4wd)

Fluid dynamics (yes air is a fluid) can render the cooling system ineffective if airflow under the vehicle interacts differently with the air coming through the cooling system... Several cars have shown in testing here to run hotter without the undertray in place or damaged.

But hey... You come here with 6 posts to your name spouting your mouth off... What the heck do I care... I'm tired, I'm pulling 12 hour shifts constantly and all I can think of to pass the time is the enjoyment of arguing with someone who lives in a bloody cold climate and thinks the TD5 needs to have enhanced cooling over there... :eek: Oh please!

Feel free to NOT respond to this post.. I have no intention of continuing a Battle of Wits with an Unarmed individual.

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Originally Posted by Tombie2

Now the directed airflow through the radiator and cooling system is not being directed properly. In hot climates like over here this will result in the engines cooling system working harder than it should.

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I'll back that.....

without directing the air around the engine and letting it spill out the bottom of the engine bay your not forcing air around the engine bay and removing the heat from it.

sounds freaky but this can increase the workload of the cooling system proper..

your engine is cooled by 3 things (which always ties back to getting the heat to atmosphere)

1. the coolant
2. the oil
3. the air

most people get that the engine is cooled by the coolant the coolant circulates round the engine and then dumps heat out via the radiator not many people give any thought to the fact that the oil and the air in the engine bay provide important assistance to the cooling system.

if you disrupt the designed airflow in the engine bay by letting all the air dump out of the engine bay via the bottom of the fan the engine gets warmer from the lack of air circulation around the engine. Removing this heat load now becomes the job of one of the other 2 cooling mediums the oil or the coolant. Since the oil is cooled in most diesels by the cooling system proper the heat load comes back onto the radiator, increasing the work load for the cooling system.

the next argument that usually comes when trying to explain this is that the air is already heated coming into the engine bay because its already come through the radiator,intercooler and the condenser if the aircon is on. Now thats true but doesnt count for the fact that if the air around the engine is cooler than the engine itself then the engine will still offload heat into the air.

mmm, not sure I agree or disagree either way tbh, but you could look at this way, "if" the tray is off, the air rushing below the car will cause a venturi effect and draw the heated air from the engine bay down and out under the car, that air will naturally draw heat away from the engine / engine bay.

I know we dont get the temps you guys do, but I must say when its +30 degrees c here I dont seem to suffer any issues and my tray has been off since I have had the car.

Also, if people are that concerned about altering factory airflow, then even fitting the likes of an ARB bumper and big spotlights etc will technically affect it as well.

THE best thing anyone can do is to fit a Saudi spec mesh grille, that does make a huge difference to the amount of airflow going into and through the rad, hence all the middle east D2's have them from the factory. If it makes as much difference with cooling in the summer as it does slowing the "heat up" process in the winter, its well worth the investment imo.

while most of what Ive written is from memory from the cooling system maintenance part of the mechanics course.

I know that it doesnt make any difference to the defender (but the td5 is not as confined in that engine bay) as it only has the sound insulation around the engine and not the air flow panels as fitted to the disco 2.

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Originally Posted by Tombie2

Physics states heat radiating away results in a cooler temp? Not if the temperature is sustained... Or perhaps a cool spot occurs on the head does it? so the 5th pot is colder than 1 thru 4... Please....

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Wrong.

Heat that has radiated to the bulkhead (your own words) is energy that has been 'removed' from the overall system. You will also note that the cooling system had no part in this, hence the total energy budget is less and the cooling system has a little less 'work' to do.
Note the geograhic distance here from the business end of the cooling system and consider whether it is better to allow a little extra heat to escape from this part of the engine.

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Several cars have shown in testing here to run hotter without the undertray in place or damaged

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this is actually interesting, would be interested to know how this testing was carried out and debate maturely on this point as it is believed by more than me, that the undershield removal assists engine cooling.

However both views cannot be correct.

Were these td5 discos?, was there a control car? how close in age/condition was it to the main test car? How were variations in local weather accounted for during the test?
How was the temp measued? how many times were the tests repeated? is there a physical record of the tests and the results?