***
I am renaming this thread to cover the fact I had initially misdiagnosed the overheating/performance loss to be due to the radiator, where as in reality it was due to using a cheap fuel filter (read upwards from the bottom of this thread!)
***



Hi all
I have been googling everywhere to try and establish when a 2.2 freelander 2 dual cooling fan should kick in. Mine works with the ac but I took the engine to 97 degrees (read by odb) with the ac off and the fans did not turn on. Seems wrong. The effect for me looks to be transmission over temperature and air intake values too high. Ruined my atf and makes car run at half power after heavy traffic or towing.

I can't understand how a can bus driven fan controller can respond to ac demand but not water temp.

Ideas??

James

Last edited by jtq4u on 13th Aug 2019 3:21 pm. Edited 1 time in total

Quite a few things influence the Engine Cooling Fan and it is controlled via the Engine control Module.

Fault are stored and can be read with an OBD reader. What does your car think is going wrong?

Engine Coolant Temperature (ECT) Sensor
The ECT sensor is located in the thermostat housing, on the front of the engine, below the inlet manifold. The ECT sensor is a thermistor type sensor used by the ECM to monitor the engine coolant temperature. The ECM uses the temperature information for the following functions:
regulate the injection period
set engine idle target speed
control the engine cooling fan(s)
determine operation of the A/C compressor
determine operation of the purge valve and catalytic converter heating function.

The sensor is a Negative Temperature Co-efficient (NTC) thermistor element. The element resistance decreases as the sensor temperature increases. The ECM supplies the sensor with a 5V reference voltage and a ground and measures the returned signal as a temperature.

The ECT sensor is important to the correct running of the engine as a richer mixture is required at low engine coolant temperatures for efficient starting and smooth cold running. As the engine coolant temperature increases, the ECM uses the temperature signal from the sensor to lean off the fuel mixture to maintain optimum emissions and performance.

The ECM monitors the ECT sensor for faults and can store fault related codes. These can be retrieved using a Land Rover approved diagnostic system.

If the ECT sensor fails, the ECM uses a default value of 90°C (194°F). The electric fan control module is sent a default coolant temperature value of 105°C (221°F) and switches the cooling fan on permanently.  FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 79k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Hi
Thanks for the reply. The more information I can gather the better.
I am not getting an error about the coolant temperature sensor and I can observe it via my OBD display (I have an android in car setup, displaying graphs from data sent via a bluetooth dongle). I can see the temperature rise as expected. I would assume the coolant temperature shown by OBD is the one that comes from the aforementioned sensor?

The symptoms I have experienced are an OBD code for Transmission over temperature which then after a 100 mile tow resulted in gears thumping on unexpected down changes! Then I started getting codes stating various gear ratios were wrong and that the lockup cluctch wasn't working. Again due to the ATF fluid having been distroyed. Whilst on the holiday I went to a relatives place and changed the ATF fluid (using the correct spec, sourced from a land rover independent). That made the box run OK again, but on the 100 mile trip home it has been over temperature again (and so gradually distroying my new fluid I expect).
So that is one symptom.

By coincidence I watched the graph of Intake temperature and noticed it to be way too high - 50 to 60 degrees when I would expect it to be 40 - 45 degrees (10 - 15 over ambient). So I wondered if it was the intercooler at fault. Thus I got to where I am now in observing that the cooling fan never comes on except as commanded by the AC. Turning the Ac down to max coldness makes the fans run faster and the intake teperature be correct - which epxlains why the first half of our journey was ok (before we turned ac up to 21 degrees).

Thus the question - when should the fans start turning - mine don't turn when the coolant is at 97 degrees. This seems wrong?

thankjs

James

Is your transmission cooling circuit working? Is your Thermostat working correctly? Is your Ambient Air Temp sensor working (in door mirror)?

More from the manual

Engine Normal Operating Temperature

With the coolant temperature increasing, at 83°C (181°F) the thermostat reacts and commences opening. The by-pass valve is progressively closed. Hot coolant returning from the engine to the thermal control module is now allowed to pass through the top hose connection to the radiator. The flow of hot coolant to the radiator now forces cold coolant within the radiator and bottom hose to flow to the thermal control module.

During the thermostat opening period there is an initial temperature differential of the coolant at both sides of the thermostat. The thermostat reacts to the temperature differential and partially closes, while the by-pass valve opens further. The thermostat and by-pass valve continue to oscillate while the coolant temperature increases.

At a coolant temperature of 91°C (196°F) the thermostat is fully opened and the by-pass valve is fully closed. The return coolant from the engine is now fully circulated through the radiator and bottom hose. Coolant flows through the radiator from the RH tank to the LH tank, and is cooled by air passing through the matrix. Entrained gases in the radiator escape through the connected degas line to the coolant reservoir.

The increased coolant volume created by heat expansion causes the coolant level to rise through the connecting reservoir hose, and into the reservoir.

The temperature of the cooling system is constantly monitored by the ECM via the ECT sensor signal. The ECM uses the ECT signal to control operation of the cooling fans, and to adjust engine fueling. The ECM also operates the fans in response to inputs from the automatic transmission oil temperature sensor, Air Conditioning (A/C) system control switch, and the A/C pressure sensor. For additional information, refer to: Electronic Engine Controls - 2.2L Diesel (303-14 Electronic Engine Controls - 2.2L Diesel, Description and Operation). For additional information, refer to: Air Conditioning (412-01 Climate Control, Description and Operation).

The cooling fan speed is also influenced by vehicle road speed. The ECM adjusts the speed of the cooling fans to compensate for the ram air effect, using the CAN bus road speed signal received from the Anti-Lock Brake System (ABS) module.

When the engine is shut down, the coolant temperature and volume decrease. The thermostat starts to close as the coolant temperature decreases to 89°C (192°F), and is fully closed at 81°C (178°F). The coolant level within the reservoir decreases as coolant is drawn from the reservoir to replenish the system.

Following engine shut down when the coolant pump is stationary, the ECM may continue to operate the cooling fans for a pre-determined period to maintain engine cooling. FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 79k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Just been reading my copy of the manual including the above
Shame it never actually mentions temperatures when the fan comes on. It only says it varies speed via pcm. It only mentions temperatures the stat opens and closes.
Ambient temperature reading is correct in obd.
Have not yet taken atf heat exchanger out for inspection. But would find it handy to know what temperatures someone's fan kicks in at with ac off. I guess it needs to be someone with obd reader so they can monitor coolant temp when it kicks in.
Air intake temperature readings seem too high post intercooler. They are probably valid given they become good with ac forcing fan on.

If the default ECT is 105C in the event of a sensor failure, and that switches the fans on, could that imply the number you're after is 105?

How is the trans cooled? I'd have thought ATF temp is independent of the engine coolant temp, esp with a separate heat exchanger.

Ponderings only, no knowledge underpins this reply. MY11 SD4 SE Auto

Hi Jeff,

The Transmission is cooled via a heat exchanger using the radiator water. So if the radiator water gets hotter than usual (but still is able to keep the engine cool via a fully open thermostat) then the transmission will raise in temperature but the engine could stay at a middle gauge position.

Not sure if the fact it uses a value of 105 for default definitely confirms thats the lowest temperature it comes on at - that seems very high for a fan, especially given that this is a variable speed fan. I expect it chooses 105 as this is the worst case - demanding full power fan. It must assume the worst I would hope! So there will be very likely temperatures below this where the fan should spin slower. I guess given that I observed no spin at 97 degrees this does imply I have something wrong.. because the range 97 to 105 degrees seems quite small for the full range of fan speed.

Still ultimately I would love someone to turn off their ac.. warm the car up to normal temperature (or if they are a technical person like me they can use obd to monitor coolant tepmerature) and see when the fan kicks in!
Then I will know for sure I have an issue. Of course I still won't know if it is the car ecu, the fan ecu or the fans that are to blame. Unlikely to be the fans because they do spin for AC demand.

Thanks

James

PS I have just bought an osciliscope from amazon to get delivered later this week so I can then look at the pcm signal being sent to the fan control unit.

Further testing today shows that the fan kicks in at around 97 to 98 degrees - which mine does.
So I guess that isn't the reason for the slow down after traffic or when towing

I can only assume that the car is throttling back the fuel for some reason, perhaps unintentionally.
Maybe it is the fuel system it self.

I have investigated under the car and checked the turbo output hoses today. They look sound, however the input hose does not.. there has been a lot of oil coming out of the plastic downpipe to rubber union at the turbo. It is everywhere. I cleaned it up, and remade the joint, using some hilomar blue for good measure. I guess tomorrow we will see if that fixes my loss of power when the engine is warm. I am not sure how a leak pre-turbo could cause that? Perhaps because extra air gets in, so that the MAF reading is wrong.. resulting in underfuelling.

OK providing feedback on this one in case anyone else hits the issue.

The reduced performance when hot was caused by an interesting strategy the freelander 2 has. Initially it controls fuel pressure regulation with the PCV on the rail instead of the VCV on the pump. This causes lots of back flow along the return line from the rail. This is intentional. In the fuel filter there is a little thermostat where the return line passes over it. It should close at around 40 degrees. So the net result of the above is that initially lots of hot fuel comes back from the fuel pump (heated by the high compression) and warms up the fuel in the filter. This improves emissions by providing fuel at a constant viscosity. Once the Fuel Temperature sensor on the supply line sees fuel at 40 degrees the fueling strategy changes. The freelander stars using the VCV on the fuel pump to regulate pressure (now only using the PCV on the rail for additional regulation). So less fuel comes back along the return line. The valve in the fuel filter also closes, causing returned fuel to go all the way back to the fuel tank instead. All is then good in the world..

However.. If you put in a cheap nasty fuel filter like I did, instead of a Mann one. Then the little temperature valve sticks open, meaning that the fuel in the filter keeps rising in temperature from the fuel that is still coming back from the rail. I measured it rise to 80 degrees. This is detected by the fuel temperature sensor and makes the land rover go into a limp mode (without any sort of logged code in obd!!!).

Resolution - change the fuel filter. If you are having them regularly changed to fix such issues then consider a better brand!

How to test for this:
Start the car and rev at 2500 revs until the temperature reaches 95 degrees in the coolant (measured via obd). Confirm the car is in a state of poor performance. Now measure the voltage across the temperature sensor. if it is around the 0.7v mark (and about 400 - 500 ohmns) then you have an over temperature situation. You can IR temperature scan the filter too if you have one of these bits of kit. When in fault condition you can further prove it to be over temperature by *(temporarily just for the test** replacing the temperature sensor with a 2k resistor. Suddenly the car will be fine again. Test very briefly to avoid permanent engine damage.

As I say the fix is a new fuel filter.

Bloody hell, well done.
How on earth did you pick this.
I was just fondly remembering my 200tdi Disco ... MY11 SD4 SE Auto

I seem to remember that Alex Pescaru explained about the fuel filter thermostat and not using nonOEM filters. 11 GS Bali Blue
07 GS FL2. Usually muddy. Gone
Numerous LRs since 1963

Yup there you go, https://www.freel2.com/forum/post373945.html#373945

sorry I didn't read this earlier.
Dave DAVE.

I am just glad I reached the end of this journey without having to part with the Land Rover!
It is interesting to read from that link that I am not the first to hit this issue. I do wonder why they chose to put the valve inside the consumable part. Is that really common practice I wonder.

It is a shame that the side effect of this issue for me was a need to change my gearbox fluid whilst on holiday, as it cooked it towing through the Devon hills with such reduced performance. And of course now I have fixed the issue I will have to change the fluid again because it also suffered on the way home from holiday!

James

I have never had an issue before with any aftermarket brand of filter but reading the above and other problematic fuel filter posts this is one filter that I will only ever buy a genuine LR part for, and given the cost of the full kit from Matford Landrover there is no saving to be made by not going all genuine.  Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)