Thread: Anyone's fuel cooler have a thermostat and spring in the end?

Originally Posted by Tombie

Not true, and a similar stance has been the demise of many a vehicle with the Cooling system thermostat removed.

The thermostat has 2 functions.

Initially it helps warm the fuel, warm fuel = better flow through injectors.
Once up to temp, the thermostat slows the flow through the cooler, allowing the coolant more residence time to actually absorb the thermal load. Fast flowing coolant doesn't cool anywhere near as effectively.

There is a reason its called a "Cooler" and not a "Heater"

…. and be sure that the “flow restrictor” is installed in the fuel cooler’s lower radiator coolant feed hose.

Re needing a fuel cooler

Has been on road sort of (well, it's a landrover) and no fuel cooler is no problem at this stage.

Did some reading up and diesel has a good operating temp around 45 Celsius , lower temp than that and the gain in power due to density not enough to justify the effort of cooling it further , higher temp is for reductions in Nitrogen Dioxide and slightly better atomization but losses in density/power.

Have done a few drives with Nano attached and it is running 10 to 15 degrees cooler than engine temp with no cooler hooked up (it's on carport floor somewhere)

With fuel cooler in it was at engine temp.

HOWEVER, in the original design of my car (1999 D2) the water flow was through the completely separate section at the bottom of the radiator which I have read somewhere ( have done a lot of reading on this since my last post in this thread but no notes other than in my head and no links sorry) runs a few degrees cooler than the top engine cooling section, so fuel cooler IS a cooler not heater as diesel has additives for cold weather (how is it sposed to stop cold weather gelling when your car is switched off overnight?)

BUT my radiator has been replaced with an aftermarket unit (no lower separate section) and both the two lower nipples are part of the tank (and both open to the tank not top blocked and lowest nipple only flowing as per LR revised radiator), and my diesel temp always followed my engine temp as per pre cooler removal nano readings.

So summer is going to be interesting and I will be nano recording and picking high temp days to go on drives .

I think it operates best as a lower temp cooler in its pre LR radiator mod iteration and in the later revised radiator with no separate lower section and the oil cooler bypass outlet/inlet blocked it operates as a higher (engine temp) cooler to assist with emission demands ( EU3 requirements? ) while still not letting the diesel temp over run..

So from this I believe that the original cooler setup fed from separate lower radiator section with feed from the oil cooler bypass is actually a good fuel cooling setup from factory, and any mods to this system should aim to keep fuel down to I think it was about 60 -65 celsius as a compromise power/emissions or lower again (closer to 45 C as possible) for power chasing.

However my aim is a reduction in plumbing so crossing arse hairs that I get reasonable fuel temps over summer without needing to put a cooler back in circuit.

My diesel temp information is from BP and SHELL papers that I perused in my online wanderings.