Something doesnt sound logical here

Guys, i'm thinking and overthinking on this and doesnt seem right to me, starting from here:

COOLING SYSTEM - TD5 said:

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 82C. 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.

Click to expand...

correct me if i'm wrong but the fuel goes into the cooler on the return as it comes out from the FPR where the temp sensor is, all the official diagnostic guides are stating that in normal operating conditions the fuel temp is 10*C below the coolant temp, confirmed by loads of live data logs i've seen in which actually 75*C fuel temp was tops... so what's the purpose of that cooler then???...other than being friggin' expensive and commonly be the source of coolant leaks or even worst fuel in coolant ingress issues???, unless there's some reason to heat up the fuel to the coolant's temp which i'm missing but then they should have named it ''fuel heater'' not ''cooler''... IMO this bit is completely useless there so as mine started to leak i'm thinking seriously to bypass and get rid of it completely

somebody tell me what i'm missing here

Wild guess here: can the Td5 get a vapour lock due to the fuel being too hot? Even though it's injected diesel and not carburated petrol?

the gist of this dillema of mine is that i've never seen higher fuel temp than coolant temp readings in all the live data logs and i've seen some also i have nanocom on board as instrument most of the time so as the fuel temp sensor is in the FPR before the cooler on the return line then after the cooller if both temps sre equaluising that "cooler" is more of a heater isnt it?

I would like to know also as mine is still dripping coolant when cold! So if I can remove it that would be great

Your logic looks sound. It would be interesting to bypass it and monitor the fuel temperatures - ideally back to back with a log with it connected.

i'm thinking now to the easyest way to fit a temp sensor exactly on that fuel line instead of the cooler the make some drive tests with it, unfortunately i dont have the tools nor the skills to improvise a housing for a sensor on such thin pipes

A little bit of research (well, OK, Google) suggests that the purpose of the fuel cooler is to cool the diesel returning to the tank ie AFTER it's gone through the head. The fuel temperature measured by nanocom will (I think) be before the injectors.

So I think it may be useful after all.......

according to the FPR scheme(an internal flow diagram would be really good) the FT sensor is in it on the feed but the feed is splitted and the
blocked excess of fuel goes to the return where it meats the return from the head and the return port is near the FT sensor if you see what i mean, the main part of the return fuel which goes to the cooler is blocked from the feed and is mixed with a small amount coming from the head but i doubt the FT sensor will miss it as everything goes through the FPR ... and as i saif the temp measured by the FT sensor is always at least 10*C lower than the coolant temp so IMO that cooler is rather heating than cooling