Deleting fuel cooler.

[FNQLR]

Anyone here deleted it? Any issues?

mine has failed for the last time. :(

Redoing the plumbing and fuel lines as we speak.
This pos is going in the bin. The engine bay will be so much neater.
Hopefully the old girl won't explode.

[shack]

Anyone here deleted it? Any issues?

mine has failed for the last time. :(

Redoing the plumbing and fuel lines as we speak.
This pos is going in the bin. The engine bay will be so much neater.
Hopefully the old girl won't explode.I think JohnP38 did.

[FNQLR]

Just after a sanity check on the revised cooling circuit...



I'll be blanking off the oil cooler outlet and have removed the behind engine pipe and hose.

The two lower fuel cooler outlets of the rad will both be blanked off.

The suction side of the heater will join with the now hanging hose from the overflow tank tee (that goes to the pump inlet circuit, I think)


I think this will work all ok - disregarding the issues of going without a fuel cooler / heater

Cheers

[Dervish.]

Fuel cooler or EGR cooler?

I have the egr cooler removed and that included removing the pipe from oilcooler and from the back of the engine.
Fuel cooler I still have plumbed and good.

[FNQLR]

Fuel cooler or EGR cooler?

I have the egr cooler removed and that included removing the pipe from oilcooler and from the back of the engine.
Fuel cooler I still have plumbed and good.


Fuel cooler. The egr went a long time ago. :)

Mines a '99 td5. It just had the uncooled egr setup.

[sierrafery]

Anyone here deleted it? Any issues?

mine has failed for the last time. :(

Redoing the plumbing and fuel lines as we speak.
This pos is going in the bin. The engine bay will be so much neater.
Hopefully the old girl won't explode.
Even if it doesnt explode IMO deleting the fuel cooler is a VERY bad ideea on a Td5 ... it will become powerless once the FT gets above 75*C and without the cooler it will definitely go above... the ECU reduces the injected quantity based on FT input too also your fuel pump will fail more often getting too hot fuel on the return, especially if the level in the tank is low

I'd not do such huge mistake if i was you, you can fit a square type cooler like on the late facelifts with a bit of piping mod and that one is bullet proof, it'll last more than the vehicle

[FNQLR]

Even if it doesnt explode IMO deleting the fuel cooler is a VERY bad ideea on a Td5 ... it will become powerless once the FT gets above 75*C and without the cooler it will definitely go above... the ECU reduces the injected quantity based on FT input too also your fuel pump will fail more often getting too hot fuel on the return, especially if the level in the tank is low

I'd not do such huge mistake if i was you, you can fit a square type cooler like on the late facelifts with a bit of piping mod and that one is bullet proof, it'll last more than the vehicle


-Thanks mate, didn't realize there was a better version. I'll hunt one down.

[sierrafery]

-Thanks mate, didn't realize there was a better version. I'll hunt one down.

search for PIB000080, even if it's used not much to fail on it as long as it wasnt physically hurt, a friend of mine addapted a D3 cooler (PIB500052) which is cheaper, a T piece is needed instead of the old cooler's coolant outlet, i have such a cooler prepared for when my original fails

[FNQLR]

yep, dumb idea to remove the fuel cooler.

I like the idea of these air cooled units. Seems like the lowest the LR heat exchanger type will go is ~ 70c


https://www.youtube.com/watch?v=HDiw2qkQVYM&t=602s

[sierrafery]

yep, dumb idea to remove the fuel cooler.

I like the idea of these air cooled units. Seems like the lowest the LR heat exchanger type will go is ~ 70c

. :BigThumb: I'm glad you realised that m8... on simple logic you can presume that without the cooler the FT is quite the same with the engine temp, or even higher and the fuel density compensation kicks in, see what happens above 75*C here: Fuel Density Compensation maps | DiscoTD5.com (https://www.discotd5.com/td5-tuning/fuel-density-compensation-maps) and the pump will not feel well at all when it's not much fuel in the tank and gets 90*C hot fuel on the return.

at the end you can improvise the best way you can with any kind of cooler which fits just lower the FT somehow... in a nutshell, the lower the FT is the more power you get, that's why they run a bit better when you fill the tank with a lot of cold fuel on a hot day

[admiralranga]

yep, dumb idea to remove the fuel cooler.

I like the idea of these air cooled units. Seems like the lowest the LR heat exchanger type will go is ~ 70c


Less relevant here but I do suspect the coolant ones do a decent job of warming the fuel up when it's very cold.

[sierrafery]

Less relevant here but I do suspect the coolant ones do a decent job of warming the fuel up when it's very cold.No, IMO it's not the case cos the fuel returning from the head can't be colder than the coolant returning from the radiator whatsoever(these are passing through the fuel cooler), when it's cold it's like the cooler is not there... hence the cooler's thermostat(which the newer square type coolers dont even have):

Fuel cooler
The fuel cooler is located on the right hand side of the engine and is attached to the inlet manifold. The cooler is
cylindrical in design and has a coolant feed connection at its forward end. A 'T' connection at the rear of the cooler
provides a connection for the coolant return from the heater matrix and coolant return from the fuel cooler.
The 'T' connection houses a thermostat which opens at approximately 82°C. This prevents the cooler operating in
cold climates.
Two quick release couplings on the cooler allow for the connection of the fuel feed from the pressure regulator and
return to the fuel tank. A counter flow system is used within the cooler.
Fuel flows around a coolant jacket within the cooler and flows from the back to the front of the cooler. As the hot fuel
cools travelling slowly forwards it meets progressively colder coolant travelling in the opposite direction maintaining a
differential cooling effect.

[FNQLR]

I just picked up a late 2A rectangle style cooler, the size difference between it and the older cylindrical unit is amazing.

I'm sus on it, we're talking an order of magnitude smaller? re; surface area.

[sierrafery]

I just picked up a late 2A rectangle style cooler, the size difference between it and the older cylindrical unit is amazing.

I'm sus on it, we're talking an order of magnitude smaller? re; surface area.
No reason for suspicion, they work well enough, the size is not so important cos it's a different, more efficient technology... those for the TDV6 are not much bigger

[laney]

can someone put a diagram of how to plumb the D2A fuel cooler to a D2 this would be great thanks.

[FNQLR]

can someone put a diagram of how to plumb the D2A fuel cooler to a D2 this would be great thanks.

You'll need a tee piece to replace the old one of the cylindrical cooler, and a heap of new hoses as the early ones don't fit.

I've decided to just fit an air cooler to mine for this reason - it's just too ugly a setup with diy hoses.
Will be running the fuel through an old tranny cooler, and have blanked off both lower spigots on the radiator, and also the oil cooler.

It does neaten up the engine bay considerably, I can now see into the chasm of chafe that is the inlet side of the engine. Can even reach the starter top nut from the guard :)

[Tins]

Even if it doesnt explode IMO deleting the fuel cooler is a VERY bad ideea on a Td5 ... it will become powerless once the FT gets above 75*C and without the cooler it will definitely go above... the ECU reduces the injected quantity based on FT input too also your fuel pump will fail more often getting too hot fuel on the return, especially if the level in the tank is low



I spoke to my local indie about this very thing, and he said the same thing. Don't do it, he said.

Very interested in the idea of using one out of a D2A or D3 though. That's just plumbing.

[BradC]

I just picked up a late 2A rectangle style cooler, the size difference between it and the older cylindrical unit is amazing.

I'm sus on it, we're talking an order of magnitude smaller? re; surface area.

I'm not a 2/2A person, but from what I've read the 2 cooler is a shell and tube and the 2A is a flat plate. If that is the case, you probably underestimating an "order of magnitude". The efficiency difference between the two would be *significant* and the heat exchange surface area would be at least an order of magnitude increase and the turbulence with a flat plate is significant increasing the heat exchange efficiency considerably. I am a D3 driver, and the fuel temp increase on the high pressure side of the fuel system is significant. If you don't cool it, "bad things" will happen. Not just the de-rating, but loss of viscosity affecting the lubrication of the pump and injectors.

Manufacturers don't put parts in "just because". Every part incurs a $$ penalty. It wouldn't be there if it didn't impact driveability or reliability.

[FNQLR]

Just did an 80k trip sans cooler to see / baseline

coolant temp of 82 deg
ambient temp of 14 deg (melbourne :( )

1/3 tank of fuel

city and hwy driving

Maximum fuel temp of 66, average around 62
Running cooler than with the fuel cooler fitted.


I can image that with an outside temp of 40 degrees this would be an issue, could be looking at high 90's ?

[sierrafery]

can someone put a diagram of how to plumb the D2A fuel cooler to a D2 this would be great thanks.
See the diagram, all you need to do is to connect a T with a short piece of hose to the "water out" from the new cooler instead of the old cooler's outlet/thermostat and all the pipes to the proper ports if you see what i mean... if it's unclear just ask and i'll try to explain better

cheapest quality aftermarket i found is Hella 8MK 376 749-791

[FNQLR]

See the diagram, all you need to do is to connect a T with a short piece of hose to the "water out" from the new cooler instead of the old cooler's outlet/thermostat and all the pipes to the proper ports if you see what i mean... if it's unclear just ask and i'll try to explain better

cheapest quality aftermarket i found is Hella 8MK 376 749-791


don't forget the restrictor if still running an original radiator.
highly unlikely though

[FNQLR]

Less relevant here but I do suspect the coolant ones do a decent job of warming the fuel up when it's very cold.


I don't think it would matter too much. As far as I can tell the pump recycles a fair bit of the returned fuel - not a huge amount of fresh tank fuel gets used.

A bit like taking a leak in a pool, it makes its own warm spot.

[FNQLR]

So does anyone know what the implications of cold fuel have on tuning in a diesel?

shorter pulse width?
adjustments in injection timing?

I don't think colder fuel would make any difference regarding making the charge cooler as it's already in the cylinder when injected, but the other factors must play a part in performance / economy.

Just wondering - for better or worse?

[sierrafery]

The temperature affects density and the injected quantity depends on that, as long as the FT input is involved in the managmenet it's not so simple... go back to post #10 and see what's in that link i posted

[FNQLR]

The temperature affects density, go back to post #10 and see what's in that link i posted


Yeah i get that.

Thats all compensated for by the ecu (within reason)

The ECU adjusts Pulse Width to compensate for the denser fuel, maybe also adjusts timing?
But adjusting pulse width will also alter the timing as well (inadvertently)

I'm not worried about hot fuel, more curious about cold fuel now. As to why or even if it does enable more power.
I'll be running an external air cooled cooler, unless i'm convinced otherwise that 70c fuel is a good thing. To me the stock heat exchanger seems like a compromise between having something that will run anywhere in any climate (not a bad thing) and peak performance.


Just wondering if these changes have a positive or negative affect.

[sierrafery]

I think that an automotive engineer could explain better why they use coolant based fuel coolers and not air cooled ones... though if you know that you'll drive it when it's really cold outside think about some thermostatic bypass setup as to not let the fuel through the air cooled cooler before it reaches 70*C or it's possible to run with it overfuelled for too long

[FNQLR]

I think that an automotive engineer could explain better why they use coolant based fuel coolers and not air cooled ones... though if you know that you'll drive it when it's really cold outside think about some thermostatic bypass setup as to not let the fuel through the air cooled cooler before it reaches 70*C or it's possible to run with it overfuelled for too long

I've been running all week without a cooler of any sort - max temp was 66 deg. But this is in a cold horrible place. Not sub zero but close. You are right though, with an air cooler fitted a bypass would be needed for sure. I'll make a bag that fits over the cooler for winter running (if i'm still stuck in this hell hole)

[simonmelb]

If needed I can take a pic of my D2a which was converted to the new type about 11 years ago and no problems since. Was done by Fred Smith who used all original LR parts incl hoses.

[shack]

I wouldn't overthink all this stuff guys.


The LR technical info says the fuel cooler is for "optimum performance and emissions"

The fuel is kept within a certain temp range as it enters the head/injectors.

The difference pointed out above as regards timing being affected is true, but the difference is negligible..I wouldn't worry about it.

The TD5 engine management has maps that makes allowance for different temperature fuel and adjusts pulse width to ensure the correct MASS of fuel is injected.

Personally I'd keep the cooler, it'll stop the fuel in the tank getting extremely hot when in hot weather with low fuel in the tank, it'll also lift the temp of the fuel entering the head when it's cold, I'd also view that as a win.

As a side note, I'd definitely be making sure the fuel temp sender is working otherwise you'll get poor performance results.

[Tins]

. Was done by Fred Smith who used all original LR parts incl hoses.

Which, no doubt, Fred had plenty of.

I for one would be interested in the pics. My cooler was done around 120k ago, and the car has sat for some time, so no doubt it's time soon.

[laney]

Yes a picture would be fantastic.

[FNQLR]

I wouldn't overthink all this stuff guys.


The LR technical info says the fuel cooler is for "optimum performance and emissions"

The fuel is kept within a certain temp range as it enters the head/injectors.

The difference pointed out above as regards timing being affected is true, but the difference is negligible..I wouldn't worry about it.

The TD5 engine management has maps that makes allowance for different temperature fuel and adjusts pulse width to ensure the correct MASS of fuel is injected.

Personally I'd keep the cooler, it'll stop the fuel in the tank getting extremely hot when in hot weather with low fuel in the tank, it'll also lift the temp of the fuel entering the head when it's cold, I'd also view that as a win.

As a side note, I'd definitely be making sure the fuel temp sender is working otherwise you'll get poor performance results.


I've purposely run the tank down to almost fumes (probably 5l left in the tank) just to see how hot the fuel gets without the cooler.
Didn't see any real difference, maybe 5 degree hotter. Not sure if it's a myth the 'not running tank too low' ?
but this was in cold weather.


What you said about lifting the fuel temp when cold makes sense, I could imagine a pretty big temp gradient between injector #5 and #1 as the fuel is heated by the head as it flows through. Feeding with pre heated fuel stops this.

[FNQLR]

Yes a picture would be fantastic.

X2

I think the fuel lines need to be shortened as well - for optimum neatness.

[simonmelb]

Am away from the D2 till the 11th so will upload some pics when I return!

[twr7cx]

search for PIB000080,
...
a T piece is needed instead of the old cooler's coolant outlet, i have such a cooler prepared for when my original fails


... hence the cooler's thermostat(which the newer square type coolers dont even have):

Fuel cooler
...
The 'T' connection houses a thermostat which opens at approximately 82°C. This prevents the cooler operating in
cold climates.
...

Any idea why the new square design fuel cooler doesn't have a built in thermostat like the old cylinder units do in the t-peice?

What is the change in plumbing at the factory with the newer square design cooler? Does LR use a t-peice or is there other changes to make that redundant?

[sierrafery]

Any idea why the new square design fuel cooler doesn't have a built in thermostat like the old cylinder units do in the t-peice?

What is the change in plumbing at the factory with the newer square design cooler? Does LR use a t-peice or is there other changes to make that redundant?
Unfortunately i can't give you a smart answer [bigsad]