EA81 thermo fan cut in/out points

steptoe · Post by **steptoe** » Sun Nov 06, 2011 11:34 am

On my first Brumby I am sure the thermo fan cut in just a few mm above halfway mark on the temp gauge, whereas my latest dos not kick the fan in until the 3/4 mark, drops a coupla mm to still above half mark and cuts out. I'd be happier if they cut in just above half rather than closer to disaster.

Just replaced a new 180F 82C thermostat with a 170F 77C t'stat and runs about 2mm below half when cruising now, ambient about 28C. When I come to a stop I manually switch both fans on to maintain that temp - thinking to tap into the brake switch to pull fans on whenever i am either stopped or slowing down.

I really need my watchdog to get a digital readout.....

nncoolg · Post by **nncoolg** » Sun Nov 06, 2011 11:40 am

You can just get a colder thermoswitch...

Silverbullet · Post by **Silverbullet** » Sun Nov 06, 2011 2:05 pm

I thought there was something wrong with mine because it never comes on, stopped or moving. Then you say stock is above the half way point on the gauge somewhere. Mine never gets above half thankfully.

Incidentally, where is the switch/sensor that turns the fan on? is it the one near the drain plug on the radiator?

revmax · Post by **revmax** » Sun Nov 06, 2011 4:32 pm

Silverbullet wrote:I thought there was something wrong with mine because it never comes on, stopped or moving. Then you say stock is above the half way point on the gauge somewhere. Mine never gets above half thankfully.

Incidentally, where is the switch/sensor that turns the fan on? is it the one near the drain plug on the radiator?

drivers side of the radator about 2/3 the way down.

Mine doesent work so the relay wire is just earted and th fans rum all the time.
I replaced the switch with a new one and it craped itself about a week later. starting to P me off.

Brumby Kid · Post by **Brumby Kid** » Sun Nov 06, 2011 5:31 pm

What about a switch in the cabin? Mine has two? What would be best for me to run it at optimum performance?

revmax · Post by **revmax** » Sun Nov 06, 2011 7:12 pm

Brumby Kid wrote:What about a switch in the cabin? Mine has two? What would be best for me to run it at optimum performance?

yer I might even just do that.

Smokey · Post by **Smokey** » Sun Nov 06, 2011 8:59 pm

I tested 4 thermo switches I have from various spares and found two work. My radiator has two in and not sure if they should both be open until temp is reached then they close completing the circuit to fire fan relay. Anyway 1 seems on all the time, 1 never turns on and the two working correctly turn on at approx 90C, could not tell when they turn off again, assume 85 or so. I also have a 77C thermostat. Isn't a 90C thermoswitch a bit warm in a car using a 77C thermostat?

Used water on the stove to test the switches and multimeter to measure temp.

steptoe · Post by **steptoe** » Sun Nov 06, 2011 10:18 pm

it is said 95C is most efficient temp to run an engine but too close to trouble in my thinking, used to run coldest with twin fans manually switched on would keep gauge at mid temp on the hottest of days climbing mountain passes, road melting under tread and the odd Falcon, Patrol and RX7 resting at the roadside.

I'll go digital to measure temps and check out the different range of radiator fan switches.

Silverbullet · Post by **Silverbullet** » Mon Nov 07, 2011 6:26 pm

I've got the single original thermo fan, with a mechanical fan on a belt on the other side. Since I'm not sure if my thermo switch will come on when it should (and I don't want to find out the hard way) I was thinking of putting a manual SPST switch next to the choke knob or on the other side. If I did this what is the best way? just two wires directly from the fan to the cabin with battery in between? and what amp fuse should I put in there?

steptoe · Post by **steptoe** » Tue Nov 08, 2011 11:18 am

I did that first, just a switch taped to my footwell kick panel in a hurried job, that switch got preety warm

. Ended up with a relay up front and hooked up a second AC push switch in the blank off, so lhs button does lhs fan, rhs button ......

revmax · Post by **revmax** » Tue Nov 08, 2011 3:42 pm

Just bought a thermo fan switch to screw into the radaitor.
Tridon part number TFS195 $40

phantomD · Post by **phantomD** » Tue Nov 08, 2011 7:30 pm

I can confirm that the original Brumby thermoswitch cuts in at 3/4 on the temp gauge, as I got quite a scare when I replaced the mechanical fan with a second electrical fan (for a/c) and the car was suddenly running very hot.

I believe the TFS-195 is what I substituted, although my car is now blowing up thermoswitches with regularity. The wire going to that switch is currently grounded out to run the fans all the time.

revmax · Post by **revmax** » Tue Nov 08, 2011 9:16 pm

phantomD wrote: I believe the TFS-195 is what I substituted, although my car is now blowing up thermoswitches with regularity. The wire going to that switch is currently grounded out to run the fans all the time.

When I got the car a new thermo switch was in the glove box, it only lasted a week after I fitted it before it died. I wonder if there is a wireing problem causing the switches to crap themselfs.

When it kicks in both fans turn on, is this right.

Tweety · Post by **Tweety** » Tue Nov 08, 2011 9:30 pm

this unit was piurchased from autobarn. total about $140 and well spent.

One unit fits between the thermostat and top radiator hose and this has its own temp sender unit in it.

The monitor has double sided tape and can fit on your dash. it has a voltmeter (handy) an easily adjustable "on" for the thermo fan (and auto turns off at 7 degrees less)

I dont regret buying this unit. it is hooked up to twin thermo fans.

steptoe · Post by **steptoe** » Wed Nov 09, 2011 5:25 pm

Sort of wonder if TFS195 comes on at 195 degrees F ? Now been running my 170F thermostat and it runs a smidge cooler and then can creep towards the just above half mark quickly when not rolling. It is a new water pump on a new engine with a serviced radiator.

Revmax, if you had AC just one fan would work with the thermoswitch in radiator, the other would come on with AC on. It can all depend on how it was wired up when fitted after the factory or what someone has done meantime.
I might recheck my timing as too much advance equals hotter, my mixture too as too rich equals hotter with LPG and Diesel fuels.
I am sure my first Brumby ran cooler with the coolest avail thermostat 170 - maybe 160 was around then?
I am starting to understand FROGs mate in his rally SVX with temp gauges everywhere - I'd like to know radiator water temps and see how they differ from engine. Must get another TM2 or 4

revmax · Post by **revmax** » Wed Nov 09, 2011 5:29 pm

steptoe wrote:Revmax, if you had AC just one fan would work with the thermoswitch in radiator, the other would come on with AC on. It can all depend on how it was wired up when fitted after the factory or what someone has done meantime.

thanks I will get me auto lecy mate to have a sticky beak, cause both fans come on, I am thinking that this may be the reason the thrmo switch died recently

Silverbullet · Post by **Silverbullet** » Wed Nov 09, 2011 5:32 pm

Out of curiosity, who uses a mechanical fan as well as an electric? or does everyone just use twin electrics?
I've got 1 mechanical, even on a 30 deg day in stop start traffic the gauge doesn't get above half...I hope the gauge is reading correctly

And I'll be keeping my mechanical fan

Brumby91 · Post by **Brumby91** » Wed Nov 09, 2011 8:22 pm

Did the Brumby's have mechanical fans?
If so , does anyone have a pic ?
Mine has twin electric

steptoe · Post by **steptoe** » Wed Nov 09, 2011 9:29 pm

Ones with no AC had manual fans and no electric, then if AC fitted, an electric fan went to RHS on MY models, and electric thermo fan off the rad switch went to LHS not just Brumby. Was directly off the water pump from memory - could all be BS too

phantomD · Post by **phantomD** » Thu Nov 10, 2011 9:12 pm

There was a big discussion about whether one or both fans should come on with a/c in another thread. The resolution is that both is normal depending on what year car your loom came out of - older cars, both fans come on with either the thermoswitch or the a/c. Both fans come on from either a/c or temp sender in my car.

I think a relay may be required to stop the aftermarket temp senders from blowing up - I think both fans puts quite a draw through that sender.

I miss the mechanical fan, as it would keep the engine far cooler overall. The problem with the mechanical fan was that if you were stuck in stop-go traffic, it would allow the car to heat right up as the EA81s do when constantly taking off at low speed. At which point the "panic" electric fan would come on at 3/4 to red. I do however enjoy the ability of the electric fans to work with the thermostat to keep the temperature VERY constant at just below 1/2 way.