LR3 running cold

DiscoHasBeen

Well-known member
Aug 7, 2016
1,171
262
Indy
That’s correct HasBeen, heat has been hot and consistent throughout all this. Had this thing well bled before replacing the t stat and believe I’ve got it well bled after replacing (and losing very little coolant).

Unplugged the electrical to the fan clutch, went for a drive and little change in temps. Fan was quieter. Did manage to get it up to and over 190 but settled around 190. Plugged back in later and temps were the same though the fan seemed to be running less aggressively when re-plugged back in. So a little better but seems lower than it should be
If hot air is coming out of the vents you need to replace the sensor or find a way to measure the coolant temp. If the t-stat is working properly the fan will have no control over coolant temp in cold weather. The t-stat will simply close to bring coolant temps up. Also, the poor gas milage could be due to the fact the ECU thinks the engine is running cold and adjusting the air/fuel mix I believe. Discostew might be better able to address that.
 
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discostew

Well-known member
Sep 14, 2010
7,706
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Northern Illinois
That’s correct HasBeen, heat has been hot and consistent throughout all this. Had this thing well bled before replacing the t stat and believe I’ve got it well bled after replacing (and losing very little coolant).

Unplugged the electrical to the fan clutch, went for a drive and little change in temps. Fan was quieter. Did manage to get it up to and over 190 but settled around 190. Plugged back in later and temps were the same though the fan seemed to be running less aggressively when re-plugged back in. So a little better but seems lower than it should be
So your going thru all this because you don’t like what the coolant temp reading is? Are you looking at the coolant temp sensor in the radiator outlet? It’s always piss warm. If you have no t stat codes stored just keep driving. It’s fine.
 

Howski

Well-known member
Oct 19, 2009
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Alabama
So your going thru all this because you don’t like what the coolant temp reading is? Are you looking at the coolant temp sensor in the radiator outlet? It’s always piss warm. If you have no t stat codes stored just keep driving. It’s fine.
All this started with the fan running excessively despite operating temps being low. Sounded like a turbo prop and started to impact mpg. Looking at temps via OBDii. I’m not sure if this pulls from the radiator outlet or thermostat housing temp sensor. I had l assumed sensor at the t stat housing, which I could replace
 

discostew

Well-known member
Sep 14, 2010
7,706
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Northern Illinois
All this started with the fan running excessively despite operating temps being low. Sounded like a turbo prop and started to impact mpg. Looking at temps via OBDii. I’m not sure if this pulls from the radiator outlet or thermostat housing temp sensor. I had l assumed sensor at the t stat housing, which I could replace
I'm sorry I guess I just asssumed the heat was poor because all the thermostat talk. I have not seen a cooling fan do that without storing some fault code. I have had some wiring issues because it shares that power feed with something else. I think its evaps stuff but I would have to look it up. you could get out a schematic and check those wires in the fan connector. Verify that you really have no cooling fan fault codes.
I know your tired of hearing about the air in the system, but it's the only thing I've seen cause the fan to run like your describing with no codes. I guess short of installing a known good fan, your just going to have to go over the circuit with a meter and see whats going on. I kind of think your going down a rabbit hole with the coolant temp.
 

Howski

Well-known member
Oct 19, 2009
1,483
209
Alabama
Swapped temp sensor with known good OE sensor. Apparently they are ever so slightly different in design (which you can’t see to the eye) and it doesn’t seal quite as well. This caused it to suck air into the system and blow out all coolant. Fun stuff! Think I’ll just forget about this issue for the time being…
 
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discostew

Well-known member
Sep 14, 2010
7,706
1,015
Northern Illinois
Do you have an air lift? If not can you borrow one? Never ever use one on a BMW Range Rover. But for everything else JLR is building now it’s a must have.