Cooling Fan right versus left

[LLantrisant]

my car is a Twin-Fan Aircon Model (original delivered to Japan):

watching from inside the cabin: which fan is the first to come on, which the 2nd?
the left one is higher, the right one is slimmer...no idea if this is original, or due to a replacement done in the past.

[Ice_blue_tvr]

Pretty sure the larger nearside fan should come on first.

The different sizes are standard. Iirc non-aircon models have the larger fan in the centre on its own.

[LLantrisant]

thanks for the info....i already thought its like that.....but when i recently checked (as i dont own the car that long) the slim (offside)-fan was the first comming on.....so somebody, b4 my ownership, mixed the connectors inside the enginebay.

as the 2nd (offside) fan isnt that powerfull, that might have been the reason why he couldnt cool the engine in traffic and therefore,slowly, the temperature was rising when i stuck in traffic with ouside temperatures at about 35degrees.

now i changed the connectors and double checked: nearside (left) fan connected to Relais 1.....

now i need to check in praxis if Fan2 is activated as well, as i have never seen both Fans running....

[Tony69]

Hello,

The two fans operate at different temperatures, Fan 1 (the larger fan) at 92 Degrees and Fan 2 (the smaller fan) at 94 Degrees. See the attached picture.

So the larger fan should operate first and the smaller fan operates later. If you think that one of the fans isn't working at all, check that relays 1 and 7 have a 12v supply voltage to pins 85 and 30/51 and if not, check fuses 1(25A), 3(25A) and 20(15A).

Hopefully this is helpful.
Best regards
Tony.

[ukkid35]

The fan temps are set by the MBE programming, so if you have a custom map the temps may well be different

Also, Joolz typically switches off the fans if the revs are below 500 or so

That saves power for the starter motor, which while admirable, does make diagnostics slightly trickier

[spitfire4v8]

Also, if anyone is investigating fan issues, don't put your fingers anywhere near the big fan just in case some joker has wired it backwards. Your hand will get sucked into the blades. I know

[Mr Cerbera]

Tony69 said:

Hello,

The two fans operate at different temperatures, Fan 1 (the larger fan) at 92 Degrees and Fan 2 (the smaller fan) at 94 Degrees. See the attached picture.

So the larger fan should operate first and the smaller fan operates later. If you think that one of the fans isn't working at all, check that relays 1 and 7 have a 12v supply voltage to pins 85 and 30/51 and if not, check fuses 1(25A), 3(25A) and 20(15A).

Hopefully this is helpful.
Best regards
Tony.

Superb post, Tony

Thanks a lot

[LLantrisant]

spitfire4v8 said:

Also, if anyone is investigating fan issues, don't put your fingers anywhere near the big fan just in case some joker has wired it backwards. Your hand will get sucked into the blades. I know

as far as i know on such cooling fans the direction cannot be reversed by changing the wiring.
thats why cooling fans need to be purchased as "blowing" or "suction" type.

@Tony:

thanks for the infos and what a nice enginebay!!!! compliments!!!

[ukkid35]

LLantrisant said:

as far as i know on such cooling fans the direction cannot be reversed by changing the wiring.
thats why cooling fans need to be purchased as "blowing" or "suction" type.

It really can, the connector on mine has been replaced by loose wires with blades, get it wrong and the fan will reverse

[Imran999]

Slightly tangential comment here.
I read this post with interest, as recently my car has been getting very hot in traffic.
I set about debugging the issue today, first checking coolant and then verifying the first and second fan operation (and trigger temperatures), then checked that the thermostat was opening, but I was still getting something akin to ‘thermal-runaway’ (well not really), at idle.
Turns out, my idle speed was set too low (around 900rpm). I brought this up to 980rpm and now she sits happily (30degC ambient weather), with no fans running.

Anyone know that the prescribed torque is, on the radiator bleed bolt?

Thanks

[spitfire4v8]

LLantrisant said:

as far as i know on such cooling fans the direction cannot be reversed by changing the wiring.
thats why cooling fans need to be purchased as "blowing" or "suction" type.

@Tony:

thanks for the infos and what a nice enginebay!!!! compliments!!!

They most certainly can .. that's my nail torn off, put back in place by the nurse. it didn't heal and 6 months later it's still not fully recovered. be careful

[Byker28i]

ukkid35 said:

LLantrisant said:

as far as i know on such cooling fans the direction cannot be reversed by changing the wiring.
thats why cooling fans need to be purchased as "blowing" or "suction" type.

It really can, the connector on mine has been replaced by loose wires with blades, get it wrong and the fan will reverse

But then won't cool as the blades will be angled wrong?

[Polly Grigora]

LLantrisant said:

as far as i know on such cooling fans the direction cannot be reversed by changing the wiring.

Are you thinking about DC motors with field coils as they take a little more work to reverse?

Permanent magnet motors like your cooling fan motors are also used for operating windows as they are easily reversed with switches or relays that reverse the polarity

[FarmyardPants]

spitfire4v8 said:

LLantrisant said:

as far as i know on such cooling fans the direction cannot be reversed by changing the wiring.
thats why cooling fans need to be purchased as "blowing" or "suction" type.

@Tony:

thanks for the infos and what a nice enginebay!!!! compliments!!!

They most certainly can .. that's my nail torn off, put back in place by the nurse. it didn't heal and 6 months later it's still not fully recovered. be careful

Jesus that’s nasty