Warm Fuel Fiter

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Roger 47

Member
Posts
46
Location
Dulverton, Exmoor, Somerset
Hi All
Why is the fuel filter quite warm after say about a eight mile journey. It's position is behind the o/s rear wheel and well clear of the exhaust. Is there a heater in the fuel pump unit?
Thanks for any comment
Roger 47
 
the fact that your engine, and most of the attached components get hot during use is a clue

also think about what happens to liquid when it is "injected' at very high pressures
 
I was once told the warming is done by the fuel running near/in the head and then returning it to the tank, it was designed to reduce emissions and smooth the overall running of the engine. Could be snake oil as well?

let us know if you find out anymore bearing in mind as already mentioned you should have a fuel cooler, is that working ok?

regards

Dave
 
Last edited:
It's in the head and at a great pressure, hence the cooler, it gets cooled but it's still warm - it's not a problem.

On this note: always fit the proper filter, it's the same filter as the TDI's except it's rated for warm fuel - i.e. the glue that holds it all together won't melt. If you use a TDI spec filter on a TD5 it can fall apeart inside - also the TD5 ones are plated/painted better to stop them rusting up in the arch.
 
The TD5 engines use Lucas Delphi injectors which operate at a collossal pressure, about 1,500 BAR, more than TEN TIMES a normal Landy Injector. The fuel returned from the injectors is VERY VERY HOT, and spills back into the fuel gallery in the cylinder head, which will be about 90°C during normal running.

The fuel return line passes through a heat-exchanger COOLER which is cooled by the radiator return water, and then the fuel should leave there and go back the filter at not more than SEVENTY DEGREES Celsius, which is still hot enough to cook your dinner.

To help cool the fuel the TD5 fuel system circulates about a GALLON of diesel a MINUTE to the cylinder head and back again to the filter-head and fuel pump.

It is quite normal for the fuel filter to be too hot to hold onto after a decent run. Hot fuel burns cleanly in a diesel. So don't worry about it.

CharlesY
 
Thank you CharlesY for the short course into the reason for the warm filter.
Many thanks Roger

The last one I changed was at the M6 Toll gates when the engine stopped.

The filter was so hot I had to wear a glove to unscrew it.

I was a smart-arse that time, because I was carrying TWO spare new filters!

That's a lot quicker and cheaper than a recovery to a Main Stealer. It was about 15 minutes all in from when it stopped till I drove away, and in that time they towed me away from the booth and I changed the filter.

It is well worth carrying a new fuel filter in a TD5. Because the fuel flows so fast - a gallon a minute - the filter clogs up extremely quickly if any dirt gets in, and when the engine next slows to a tickover it just stops, and won't start.

CharlesY
 
Hi CharlesY
Thanks for the additional info. Does this problem happen even if the filter is changed at LR service schedules, or if it is a low mileage use vehicle.
Thanks Roger

You could clog a filter inside ten minutes of getting one lot of dirty fuel from a garage.

As Britpart (OH NO!!) filters are so cheap buy a box of them and carry two spares. The first time you have a fuel problem and solve it in the middle of nowhere simply by slinging on a clean £5 filter, you'll feel that smug feeling of a LandyZone Smart-Arse!

I definitely did that day on the M6 Toll! One of the guys who towed me clear said he had bought a used Disco TD5 two weeks before, so he was interested in seeing the fix. He saw a fix, not even dirty hands, and I gave him a spare filter to stick in the back of his Disco.

CharlesY
 
The TD5 engines use Lucas Delphi injectors which operate at a collossal pressure, about 1,500 BAR, more than TEN TIMES a normal Landy Injector. The fuel returned from the injectors is VERY VERY HOT, and spills back into the fuel gallery in the cylinder head, which will be about 90°C during normal running.

The fuel return line passes through a heat-exchanger COOLER which is cooled by the radiator return water, and then the fuel should leave there and go back the filter at not more than SEVENTY DEGREES Celsius, which is still hot enough to cook your dinner.

To help cool the fuel the TD5 fuel system circulates about a GALLON of diesel a MINUTE to the cylinder head and back again to the filter-head and fuel pump.

It is quite normal for the fuel filter to be too hot to hold onto after a decent run. Hot fuel burns cleanly in a diesel. So don't worry about it.

CharlesY

Thanks for the clarification CharlesY.......I knew it was something like that but I just could not remember if I had read it or someone had told me,

regards

Dave
 
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