wyldecyote · Oct 2, 2014

Hi All,
Been a while since I have been on here (2009 to be exact!) having sold my 1.8 petrol I thought I would go for the Td4 this time around, but there'a a problem which isn't making much sense to me:
The vehicle is a 2004 Freelander s Td4 with a/c 115k on the clock . When the engine coolant reaches 65c the radiator cooling fans comes on at a low/mid speed and stays on (way before it should do, should be on at 100c?).
The coolant temp dash gauge (when at 80c) reads half way as it should, but the engine coolant temp never seems to go above about 80/82c regardless of town or motorway driving/load. It takes a good 4 to 5 miles of normal town driving to reach 80c from cold.
If I am stationary in traffic even for 30secs the temp will very slowly start to drop by 1c every 30 secs or so (must be the fans on) even if the temp is only 65c.
The precise readings are taken using the obd connector and my tablet, so should be spot on. Any ideas why the fan comes on so early and why the max coolant temp never goes above 80c? ...

sijwhite · Oct 2, 2014

I don't know about the fans. As for the temp, I'd say your thermostat is beginning to fail. It should get to 88ºC / 90ºC depending on load.

roccotune · Oct 2, 2014

The td4 engine is renowned as cool running and often as the thermo stat gets old and lazy the running temp drops.

The fans could be due to the AC demanding cooling or maybe a sensor issue?

wyldecyote · Oct 3, 2014

mmm thanks for your replies.
yes now that you mention it, the thermostat sticking partially open would make sense for the longer than usual warming up period and cool running. I will have to clamp one of the rad hoses and see if it warms up quicker and reaches 90/95c (watching that does not overheat)... looks like quite a job to replace though if it is faulty. The fan control seems to work on a pwm signal from the ecu, the ecu seems to get the temp reading from the thermostat temp sensor, so perhaps the thermostat isnt opening fully and the side that has the sensor in is hotter than the other side which has limited flow going through to the rad? i.e. the block may be at 90c but the radiator is 80c... do you know where the temp sensor is that the obd2 is displaying? or is it the thermostat temp sensor?....

roccotune · Oct 3, 2014

wyldecyote said:
mmm thanks for your replies.

yes now that you mention it, the thermostat sticking partially open would make sense for the longer than usual warming up period and cool running. I will have to clamp one of the rad hoses and see if it warms up quicker and reaches 90/95c (watching that does not overheat)... looks like quite a job to replace though if it is faulty. The fan control seems to work on a pwm signal from the ecu, the ecu seems to get the temp reading from the thermostat temp sensor, so perhaps the thermostat isnt opening fully and the side that has the sensor in is hotter than the other side which has limited flow going through to the rad? i.e. the block may be at 90c but the radiator is 80c... do you know where the temp sensor is that the obd2 is displaying? or is it the thermostat temp sensor?....

It is quite a job to replace the thermostat, I did it on my rover 75 but then on the freelander I made a temp fix for the winter 4 years ago tats thill going strong! A Renault 5 1.4 thermostat fits in line in the top hose and works a treat. Unlike many failed thermostats this one, from what I read, seems to fail open so can in theory be left in place with a new in line one.

Check if the fans still run the the interior fans turned off and the direction control no on any ac position (I think only feet)

digby · Oct 3, 2014

the coolant temp is certainly due to a failed (or failing) thermostat

replacement is a bit fiddly but not difficult - the issue is space down the side of the engine
Just be grateful that the Td4 has a timing chain and not a belt

wyldecyote · Oct 4, 2014

Well I turned the aircon and cabin fan off, waited for the temp to rise to 65c and the fans cut in again. So I am first going to tackle the low running temp by putting a Renault 5 thermostat in line as you suggest, I found one on ebay by QH that opens at 87c so thats now on its way

. Will tackle the fan problem after the thermostats fitted, as they say 'one problem at a time' lol and yes imagine if it had a timing belt instead of chain!

I will let you know how things progress...

Nodge68 · Oct 4, 2014

Is it an auto? If the gearbox is hot the ecu will put the fans on.

wyldecyote · Oct 7, 2014

Nodge68 said:
Is it an auto? If the gearbox is hot the ecu will put the fans on.

hi, its a manual.

Dougden · Oct 7, 2014

My TD4 seems to have developed the same problem, with the temp gauge sitting just below the middle. Weird though as it will move to normal on a good run, but during the 10 mile drive to work it doesn't quite get there.

Had a quote to replace the thermo from a local indy today......£475 incl. VAT

So may try the top hose Renault trick instead.

wyldecyote · Oct 7, 2014

while I am still waiting for my thermostat to arrive... I blocked off the lower two front grille inlets to see if I could raise the temp quicker, but didnt seem to make much difference! I have noticed that if you put your foot down you can get to 95c after a while but then falls back to 80c after you drive normal again...
A freelander being a freelander it decided to give me another little supprise today. A small puddle (size of a football) of diesel on the floor after leaving it on tickover to warm up. Turns out the high pressure fuel pump is leaking

but stops leaking when the engine has warmed up a bit (10 mins). Quoted £200+vat for recon pump and another £250 to fit... that one will have to wait I think... But I am starting to think that perhaps Rover Rons Synergy 2a that I have fitted is causing a few problems as I have had 2 injectors fail and the high pressure fuel pump now?

wyldecyote · Oct 9, 2014

quick update, tried a quick experiment today. I left the engine running from cold until 75c (it did not want to get any hotter just on tickover) and the thermostat did not open! top rad hose hot, bottom rad hose cold, and fans did NOT cut in. I gave it a few blips on the throttle at 65c and the bottom hose stayed cold, BUT when i gave it a few blips at 75c the bottom hose started to warm up until it reached the same temp as the top one... so i am guessing the thermostat fails with a lazy spring? works ok at tickover but when the water pump spins faster with engine speed (causing increased water pressure) close to the opening temp of the thermostat (if on tickover, or lower temp if driving) it causes the thermostat to open and stay open. I just need to test tomorrow if when driven moderately tomorrow from cold if the thermostat opens under pressure straight away (i.e warm bottom hose at 40c). This info hopefully will help people identify if their thermostat is faulty or a blocked rad etc...

Arctic2 · Oct 9, 2014

(Quote.A small puddle (size of a football) of diesel on the floor after leaving it on tickover to warm up. Turns out the high pressure fuel pump is leaking

but stops leaking when the engine has warmed up a bit (10 mins). Quoted £200+vat for recon pump and another £250 to fit. Quote)

Hi when you say high pressure fuel pump do you mean this one below

1

If so sometimes it is only an O-ring that can split and leak,

wyldecyote · Oct 10, 2014

hi arctic2. yep thats the one

have been quotes 200+vat for a recon one from Bosch dealer on exchange, for some reason the normal mechanic i use now does not want to do the job, and another mechanic wants to take the engine out to remove the pump (500 labor)

but have seen in the forum that you can do it with it still in the car. I dont suppose you know which o-rings fail?

A update on the the thermostat, if driven carefully/normal the thermostat does not open at 60c, so next step is to drive it hard and see if it opens

Arctic2 · Oct 10, 2014

wyldecyote said:
hi arctic2. yep thats the one have been quotes 200+vat for a recon one from Bosch dealer on exchange, for some reason the normal mechanic i use now does not want to do the job, and another mechanic wants to take the engine out to remove the pump (500 labor) but have seen in the forum that you can do it with it still in the car. I dont suppose you know which o-rings fail?

A update on the the thermostat, if driven carefully/normal the thermostat does not open at 60c, so next step is to drive it hard and see if it opens

Again i apologise for not putting your name i have noticed that a lot of members do not add their name to the about me section, anyways i have added a link below hopefully i am not breaking any rules if so sorry and a mod can remove if necessary.

This will give you an insight to how the job should be done and also the seals cheers Arctic2.

Off to pick up my first Landrover Freelander

HP Pump Replacement - The 75 and ZT Owners Club Forums

PS got these pics from a friend he says it was the little O-ring split and cost 6p to replace although he did have to buy the tool which cost £50 he now borrows it out to other members whom leave a deposit on it through Pay pal, little bit more info which may help ?

wyldecyote · Oct 19, 2014

Hi, Well I just put the thermostat in the top hose (brass cylinder pointing towards engine) and thats stopped the bottom rad hose getting warm before about 80c. Temp gauge still seems a tad low though, but could be the colder weather now having an effect too. The high pressure pump has some how stopped leaking at the moment, but when it decides to start again I think I may investigate the above o-ring info above (thanks Arctic2

) will keep you posted when work is started...

wyldecyote · Oct 19, 2014

quick update. just done some quick reading on the o-ring above. The unit its attached to is the high pressure regulator solenoid. It seems when that o-ring fails you get lack of power (due to low high pressure) and eventual hard starting, but no leaks

but are prone to common failure (on bmws) above 100k (especially if run on chipfat/bio diesel) easy to get to with starter removed though... but not a hot favorite for leaking diesel onto floor

wyldecyote · Oct 30, 2014

well i just done a short run of 1 mile today, temp went upto 50c ..... and the darned fans came on again! whatever it is its getting worse :-( i am considering cutting the feed to the fans and mounting a 95c thermal switch on the bottom hose to a relay to power the fans at 95c as i cant seem to find a clear diagram of the fan control system. it would be nice to keep it original though... i am guessing the thermostat housing has a temp sensor that goes to the ecu, and theres another sensor somewhere for the temp gauge, but there must be another one somewhere too?

Andy springer · Oct 30, 2014

The temp sensor is located in the block, you have to remove the intake manifold to be able to change it. I have just done mine, as the was a pending fault code showing for it and occasionaly with the ignition switched on the gauge would go into the red and both fan would run at max when the engine was nowhere near hot.

Arctic2 · Oct 30, 2014

wyldecyote said:
Hi, Well I just put the thermostat in the top hose (brass cylinder pointing towards engine) and thats stopped the bottom rad hose getting warm before about 80c. Temp gauge still seems a tad low though, but could be the colder weather now having an effect too. The high pressure pump has some how stopped leaking at the moment, but when it decides to start again I think I may investigate the above o-ring info above (thanks Arctic2 ) will keep you posted when work is started...

Andy springer said:
The temp sensor is located in the block, you have to remove the intake manifold to be able to change it. I have just done mine, as the was a pending fault code showing for it and occasionaly with the ignition switched on the gauge would go into the red and both fan would run at max when the engine was nowhere near hot.

Where is the temp needle when the engine is at the temperature it should. middle half way, how are you/we gauging if the thermostat is working properly or if it failed open as they do on a TD4 Arctic2

Temp sensor between the two ports bottom right of the pic

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