When should an L Series Thermo Fan turn on?

Fang · Post by **Fang** » Fri Oct 13, 2006 7:43 am

I was under the understanding that the thermo fan turned on when the air conditioning was on. However, mine appears to be turning on and off randomly whilst the air conditioning is running.

Is this normal? I can hear a relay click off in the passenger floor well area when the fan turns off. I am going to be wiring up a switch in a shortly - but I would like it to operate properly when air con is on.

Thanks!

timmo · Post by **timmo** » Fri Oct 13, 2006 8:17 am

Which fan are you referring too? the electric or the one run off the water pump? The electric fan only runs when the water temperature reaches a certain level

Fang · Post by **Fang** » Fri Oct 13, 2006 9:44 am

Yes the electric fan - this fan seems to turn on as soon as I turn on the air con on. I can tell when the fan is on - we hooked up the turbo light on my dash so it comes on when the fan does.

BlackMale · Post by **BlackMale** » Fri Oct 13, 2006 10:17 am

Yer as timmo said it comes on at a particular temp. The other alternitave is to wire it to a switch so you can turn it on and off at your leasure.

timmo · Post by **timmo** » Fri Oct 13, 2006 11:09 am

The clutch fan (run off the water pump) should engage when you switch the a/c on, but I would have thought the electric one is only switched on/off by the temp sensor in the radiator but I may be wrong.

BlackMale · Post by **BlackMale** » Fri Oct 13, 2006 12:15 pm

timmo wrote:The clutch fan (run off the water pump) should engage when you switch the a/c on, but I would have thought the electric one is only switched on/off by the temp sensor in the radiator but I may be wrong.

The clutch fan (run off the water pump) should engage once the engine is cranked and will continue to operate – it’s a clutch packed fan, any issues with this just have it re-greased. The electric 1 should depend on how its wired up, mine was on a temp however I have bypassed so that I can not turn on at my leasure – an example of this is that if I am sitting in traffic or waiting for the WA crew then I can keep the car at the lower temp by turning the 2nd fan on… why wait until it gets hot to come on? then have the temp flux while its sitting there (if you know what I mean)

Fang · Post by **Fang** » Fri Oct 13, 2006 1:18 pm

Thats what I thought too Jaffa - clutch fan is on at all times. The switch is coming - just wanted to make sure it was working properly with Air Con.

Gremlins · Post by **Gremlins** » Fri Oct 13, 2006 1:54 pm

The electric fan is running correctly, it is controlled by a thermoswitch in the RHS radiator tank AND also the operation of the airconditioning compressor. When the aircon compressor is engaged the electric fan will be on regardless of the coolant temperature. Providing the coolant temperature is sufficiently cool the electric fan will then cycle off and on in conjunction with the aircondtioning compressor which is controlled by the airconditioning thermostat in the car and this is the click you hear from under the dash. If the coolant temperature gets sufficiently hot this will also turn the electric fan on (via the thermoswitch on the radiator) regardless of what the aircon is doing and keep it that way until the coolant temperature drops back down to a more comfortable level. Hope that all makes sense.

Xtreme_RX · Post by **Xtreme_RX** » Fri Oct 13, 2006 2:46 pm

Exactly what Gremlins said....

wagonist · Post by **wagonist** » Fri Oct 13, 2006 3:32 pm

If the electric fan is not working all the time when the A/C is on, there is a problem.

The relays for this are up in the back driver's side corner of the engine bay, under the bracket that holds the little air reservior.
One is for the A/C compressor & the other is for the rad fan.
The rad fan one has a yellow wire coming out of it (this goes to the fan & the relay earths this wire out to turn the fan on).

the clutch fan will spin all the time, its just that it doesn't have any load on it when the goo inside isn't hot enough.

when the engine is off, see how hard this fan is to turn. If it spins too easily, the clutch material is part its used by date.
Subaru will want to sell you a new fan, but you can get the stuff from Toyota to suit a Landcruiser clutch fan for a couple of bucks.

Fang · Post by **Fang** » Fri Oct 13, 2006 4:15 pm

It is operating how Gremlins said (and Xtreme_RX concurred). Think I need to get that switch installed ASAP.

Least I know WHEN the fan is spinning. We checked those relays last night Steve and they seem to be doing what they do best. We also ran a lead from the power output to the fan (from relay) to the turbo light on the dash.

Maybe the compressor on the air con is having issues? Disengaging when it feels like it?

Clutch fan is working fine all the time.

timmo · Post by **timmo** » Fri Oct 13, 2006 4:32 pm

yer sorry fang i got a bit mixed up

Fang · Post by **Fang** » Fri Oct 13, 2006 5:54 pm

No prob bud!

subgiraffe · Post by **subgiraffe** » Fri Oct 13, 2006 6:09 pm

struggled to frind one of these switches for my brumby (switch not working). auto-pro had one - specs say that the thermo kicks in at 97C and off at 92C. Same thermo on every subaru from 78 to 05!! EA81,82,EJ20,20T,25 etc...

glad i didn't have to put in a gay generic hot water system thermostat to get the fan switching!

Gremlins · Post by **Gremlins** » Sat Oct 14, 2006 7:58 pm

I don't think your aircon compressor is giving up when it feels like it, actually it sounds like it is working quite well. There is a thermostat inside the vehicle that controls how cool the air coming out of the aircon is. When it senses the air is cool enough it disengages the aircon compressor effectively turning the system off. The air temperature will then start to rise and the thermostat will sense this and at a preset point turn to compressor back on to cool it down again. When all is working well you should get a continual on/off cycling of the aircon compressor. If the airconditioner compressor were to run continually I think you'd find the system would ice up and you'd get no air through the vents and things would start feeling a bit warm inside the car.

SUBYDAZZ · Post by **SUBYDAZZ** » Thu Oct 19, 2006 11:55 am

We should note herer that there are several configurations on teh L-Series. Some had jus tht clutch fan (belt driven), some had both clutch and one thermo (electric) fan, others had two electric fans. I believe that models originally fitted with AC should have an electric fan that is always on when the AC compressor is running. If it has been retrofitted then this may not be the case and it will only be operating on coolant temp.