Disco 2 Engine cooling fan

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Andy Warren

Andy Warren

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Hi all, I've replaced the condenser rad (can't get system re gassed until Monday) & finished it all today (changed oil & filters + partially drained coolant enough to just remove the two top hose connections to the coolant rail on the side of the cyl head). Put all the fluids back in but when I started it the engine cooling fan run from the off. I do run it with the external air temp. sensor disconnected so I reconnected it but still the same, anyone know where I can start looking ? Thanks in advance.
 
I've tried swapping relay R4 for R5 (cooling fan & screen wash respectively) but still the same so my faulty relay theory goes out the window :(.
 
When you say engine cooling fan guess you mean the aircon fan ?
It's my understanding it should only come on over a certain exterior temperature to supplement the viscous fan.
Don't know why it would suddenly start working though.
 
If the td5 engine has seen an over temp situation it will lock the a/c fan in, only way to stop it is with diagnostics.
 
Hi, yeah the air con fan (if you look in Rave it calls it the engine cooling fan). If you disconnect the outside air temp. sensor, (@sierrafery recommendation) it brings that fan on whenever you operate the air con otherwise that fan won't cut in until the outside air temp. hits 35 degrees regardless of whether you have the air con on or not which is why so many of them seize up through lack of use🙂. In these situations I always think it's something I've touched or done. I did disconnect the coolant temp sensor connector & all the coolant that came out went back in to the same level as before & the temp. gauge on the 'test drive' went to halfway as always. The fact it did it from cold is strange.
 
lynall said:
If the td5 engine has seen an over temp situation it will lock the a/c fan in, only way to stop it is with diagnostics.
Click to expand...
Thanks for that. As it did it straight from cold it is a bit weird & it doesn't do it with the ign. just in pos ll only when it's started. I'll plug my Foxwell in & see if it's logged anything & check coolant temp. reading.
 
lynall said:
If the td5 engine has seen an over temp situation it will lock the a/c fan in, only way to stop it is with diagnostics.
Click to expand...
Must thank you, I've just put the Foxwell on it & it had indeed logged an over temp. situation so I cleared the code & hey presto no fan, must of happened when I switched the ign. on with the temp. sensor disconnected :rolleyes:, time for (another) celebratory 🍺 🍻,all the best.
 
What I find interesting is running the vehicle with the outside temp sensor disconnected. Apart from the ac fan doesn't anything else rely on knowing what the outside temp is?
 
As @Landmark2 says it's for the outside temp only (when you press the EXT button on the ATC unit) but with the sensor disconnected the 'air con' fan comes on when you use the a/c just like it does in other vehicle & as far as I understand it, it reduces the pressure in a/c when used like it. Quite why LR did it like this who knows.
 
Just there :).
 

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Does his fan work? Because as I said he won't of heard it unless the o/s temp is above 35 degrees. You could disconnect the coolant temp sensor & run it but like mine you'll need to clear the over temp situation.
 
Andy Warren said:
Does his fan work? Because as I said he won't of heard it unless the o/s temp is above 35 degrees. You could disconnect the coolant temp sensor & run it but like mine you'll need to clear the over temp situation.
Click to expand...
He has a Foxwell so we could clear the fault code. Looks like a pain to get to when you have spot lights, might not bother.
I know his fan spins so atleast it hasn't seized up.
We have had the coolant sensor disconnected before but since it was reconnected before ignition was switched on it wouldn't have logged a fault.
 
Anaconda said:
He has a Foxwell so we could clear the fault code. Looks like a pain to get to when you have spot lights, might not bother.
I know his fan spins so atleast it hasn't seized up.
We have had the coolant sensor disconnected before but since it was reconnected before ignition was switched on it wouldn't have logged a fault.
Click to expand...
There is probably another way of testing it, pulling R4 relay in the eng bay fuse box & bridging contacts ?
 
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