What is it???

[justfishn1]

Hi, didn't quite know where to put this..
On the passenger side of the SR5 d4d auto front near gearbox, there is something that looks like a heat sink. At first I thought it may be the cooler for the auto trans, but Ive noticed from the fuel tank there are 2 lines. One goes up past the firewall into the enginebay and the other goes to this item. Another comes off it and that goes up the firewall into the engine bay.
I am just wanting to know what this is. Its approx 30 cm long by 13cm wide and runs parallel to the car. It is made of aluminium and features lots of heatsink type lines running the length of it.
Someone please help..
Cheers

[KTM525EXC]

its a fuel cooler because the hiluxes have black plastic tanks, the fuel gets warm

[justfishn1]

Thanks Ktm, thats what i thought but was not quite sure as I hadn't heard of it
Cheers again

[9W6VX]

Fuel cooler are standard for the 3 litre D4D (1KD-FTV) but we only have the 2.5 litre D4D (2KD-FTV) which does not have the fuel cooler.

Sucks........

[Triggy03]

Have you had fuel issues 9W6VX??

[9W6VX]

No fuel issues to date.

She's coming to 3 years soon by July 2009.

[KUN26]

Having a good look under the rig today after dropping the oil I noticed my heat sink wasnt looking too flash.The fin's have been pretty much mashed. I have an after market LR tank in any case.
But why would you need to keep diesel cool? I dont quite get why this heat sink is there.
I suppose most other heat sinks out there on your rigs are pretty mangled too?

[Skog07]

KUN26.
Delivering cooler diesel increases performance of the fuel is more dense at a cooler state. Im not sure if the fuel pump recirculates through this cooler as when something is pressuried it also heats up.
It sort of works in a similar way to the intercooler for the turbo. The turbo pressurises the intake air which heats it up and causes it to expand. The intercooler cools it after to turbo to increase the density of the air to give better performance for the same boost pressure...
I dont know if you have noticed it but can you tell the difference between running your hilux on a stinker of a hot day the compare it to how it runs on a cool night..
I dont know if I have explained it properly some others may be able to chime in.
Cheers
Skog

[Chancha_Blanca]

KUN26, its like drinking cold beer or warm beer, what would you prefer??? Cheers

[Skog07]

Marcelo..
I looked into the Cold beer - Warm Beer explanation. It has it merits.... I tend to consume cold beer faster than warm beer but overal performance does slow down when drinking cold beer...

[Quinny34]

KUN26, its like drinking cold beer or warm beer, what would you prefer??? Cheers

Couldn't have put it better myself!!

[KUN26]

KUN26.
Delivering cooler diesel increases performance of the fuel is more dense at a cooler state. Im not sure if the fuel pump recirculates through this cooler as when something is pressuried it also heats up.
It sort of works in a similar way to the intercooler for the turbo. The turbo pressurises the intake air which heats it up and causes it to expand. The intercooler cools it after to turbo to increase the density of the air to give better performance for the same boost pressure...
I dont know if you have noticed it but can you tell the difference between running your hilux on a stinker of a hot day the compare it to how it runs on a cool night..
I dont know if I have explained it properly some others may be able to chime in.
Cheers
Skog

Spoke to a diesel mechanic RE this one, its actually to cool the fuel returning to the tank. Due to the heat generated by the pressure in the common rail, the fuel/diesel in the return line needs to be cooled.
Maybe cooler diesel would give better performance but in the case of the Hilux, its to cool the return fuel (diesel/peto).

Your dead right on the summer Vs Winter performance. I guess for those those of us that dont have performance chips, just think of the difference as the extra ponies you get in winter versus the sluggish D4D on a 40 degree day. I imagine that the "chipped" D4D performs nicely on a 0 degree morning.

[olcoolone]

Kun26...spot on, the cooler is used to cool the diesel down to reduce latent heat and the diesel changing state.

In other word evaporation when it returns to the tank, if the diesel was evaporating as it reentered the tank it would turn into a vapor and vent to the outside air increasing fuel consumption and emissions.

Think of it like a glass of water, the more heat (energy) you put into the glass of water the faster it evaporates....and the glass becomes empty.

So if you have a glass of water, the lower the temp is the less evaporation will take place.

With CRD engines generating over 20,000psi of pressure in the injector rail, when you increase pressure the temp also rises.

And when the temp rises a state of change occurs from liquid to vapor.

There is no effect on heating the diesel that is a liquid already in the tank, it's all to do with when the diesel enters the tank, as the return diesel from the return line drops into the tank in open air and not into diesel.....hope it make sense sort of.




Cooler diesel will decrease performance unlike a petrol engine due to the fact diesel need heat to work and produce power (Why do they need glow plugs ).

IF it did work you would have to lower diesel temps to below freezing point because as the pressure of the CRD engine increases so would the heat, this would increase waxing of the diesel.

The reason you get more power on colder days is the air is more denser, so you could say at sea level on a average temp day you may be running 24psi boost and on a cold day this may increase to 25psi due to the air being denser and not because the turbo is boosting higher.

On a hot day the air is less denser then on a cold day.