EA81 overheating after a/c install

[phantomD]

Hi all,

Some of you may be aware that I have just fitted an a/c system to the Brumby - see this thread - and I was very concerned about removing the existing mechanical fan and its effect on engine temperature. Well, it looks like my fears have been confirmed. When the a/c is on (both electric fans going all the time) everything is OK, but when it's not on (not usable at the moment) I'm finding that the EA81 is overheating terribly. The problem from my perspective is that those twin radiator fans simply do not come on early enough before the engine has a chance to heat right up towards hot on the gauge.

I would like to modify the system so that these fans trip in much earlier around (or just under) half way on the gauge, instead of 3/4 hot or further. I have done a forum search and found many excellent threads where people have had similar issues but still not found the exact answer I'm after. What I don't understand is exactly what is involved. With the hot climate we have in Brisbane I want to see and hear those fans running a lot more often than they do. Unfortunately, with the hot climate we have in Brisbane, I don't want to pull the a/c and put the mechanical fan back in. Then again, with the hot climate we have in Brisbane, I don't want to cook the EA81 because it is low kms and the best thing about this Brumby.

From the threads I have read, it seems that fitting the Tridon TT2041-170 high flow thermostat will help the engine to cool down much better. Will there be a severely adverse impact in winter using this thermostat?

But what about getting the fans to automatically come on at a lower temperature? I do not want to have to manually switch them on from inside the cabin. Does the key lie in purchasing a different thermo switch, and if so, what type? Tridon's website list the TFS 195 switch 90C to 85C. According to a Subaru manual I have sitting here the factory switch is from 95C to 91C. Does this mean a) the fans will come on earlier or b) the fans will run longer when they do actually come on?

Please excuse my ignorance, but even non mechanically experienced people like me recognise the value of proper engine cooling. And with an EA81 that's only just hit 20 000kms, this becomes even more of an important thing to get right.

Thanks in advance.

[BBoypebs]

Normaly the fans come on when the temp gauge is at 3/4". I had issue's with the temp switch, In the end I replace it with an adjustable one.

[steptoe]

I have found with my L EA82T that the thermo fan comes on at 86C. However I turn my manual switch on whenever stopped, or in the burbs, up mountains, in carparks etc when temp is only 77C. I would be happy to let a switch turn my fan on lower than 86C. Some of the pollution controls on EA81 and 82 for choke off or egr or secondary throttle action are controlled by temp senders. Find and experiment. Some are not even in water but metal brackets bolted to inlet manifold. Or go see a radiator crowd to see if they have fan on switch listings with a better temp say 80C

With my EA81 with twin fans I have a switch each and only the original cooling fan comes on also with the switch in radiator at about 3/4 or 86C? It can run to hot if I let it manage itself. Also run the bigger bore thermostat also colder. Someone said genuine already are bigger bore so standard aftermarket not good enough in same cases. They are almost a universal fit and design to suit a wide range of cars.

[Point]

it may be worth fitting an aftermarket guage, even temporarily, to see what temp the engine is actually running at. It may not be overheating at all.

if it is getting hot then I would probably look for a temp switch that has a lower switching point.

[brumbyrunner]

Unless your radiator was reconditioned recently, I'd be either getting it done or buying a brand new one. It's the only way you can guarantee it's not the problem.

Don't worry about the effectiveness of the twin electric fans. There were thousands of factory fitted air-con Brumbys sold that never overheated. Mine would sit on 145 in 45 deg heat.

If you still want the fans to come on earlier, like has been suggested already, an override switch on the dash is pretty easy to rig up.

[AlpineRaven]

Someone i've seen has made an variable switch controller so the fans will come on earlier or cooler parts etc maybe something you could look into that?
That thermostat wouldn't make much difference in winter, I would guess it would warm up quicker?
Cheers
AP

[steptoe]

Davies Craig used to do an adjustable fan switch. Only prob was preventing leaks as its sensor slid in with rad hose fittings.

An idea, if you come back in to look, was to fit up a circuit so fans would come on whenever brake lights on - say in traffic, car parks etc, additional to anything else - to add some automation to the set up

[hack92]

In my 1992 brumby I have both fans hooked up to run when ever the ignition is on even if the air con is not on. The gauge shows the needle below the middle white line by a couple of mm. With the air con on it gets to the middle white line and stays while traverling and may go up a bit when stopped in traffic but there are no problems of it going past there. I have a fully rebuilt ea 81 in it with a new radiator $300.00. I feel its worth having a new one as you know where your at but its personal choice. Have had it like this since Feb 2009, went through cooler months with no problems regarding running too cold. I also have coolant (a must) in radiator and an overflow catch tank fitted.. An auto elec at Stones corner in Brisbane did the work for me he was very helpful and well priced, gased my air and wired it like this at my suggestion when I told him I didn't want the new motor overheating. Good luck with it.

[phantomD]

Thank you very much to all for the excellent replies. Next question - with these engines, how hot is too hot and what mean temperature would be regarded as acceptable (in degrees C)?

[El_Freddo]

Well first thing is to get an aftermarket temp guage that's tapped into a point where it will read the engine's temp.

My L series' thermo fan clicks on at about 93 degrees (engine temp) and turns off at about 90 degrees. Normal operation is 82 degrees. I don't know about Sunnie the brumby as he's only got the factory guage, but it doesn't move above half when he's at his hottest running temp - he's got the coupe's "sports" or "6 guage" dash. Otherwise he's always sitting on a quater.

Both thermo fans kick in when he's hot and when the AC compressor pump is engaged.

+1 for the radiator check/replacement. You'd be surprised how clogged up your radiator can be from years of service and still keep your subi going. You should be able to get a radiator joint to check the cores by removing an end tank. They'll be able to tell you that you'll need a new radiator or if your radiator needs to be rodded to remove the crap that's stopping the flow of coolant. Either way a free flowing unblocked radiator is key to chasing your temp problem.

Make sure your AC condensor is not blocked - this will not allow sufficent air to flow through the radiator to cool the EA81 enough.

To automatically turn your thermos on earlier you'll have to chase up a lower temp radiator switch to do the job for you. I don't know about the availability of these things, but I'm sure FROG or someone else out there will know.

Other wise connect up an ON/ON switch in the cab, as much as you don't want one. I've got an ON/OFF/ON switch setup on my L - it goes like this ON all the time/OFF for water crossings/AUTO, where the radiator switch does the turning on and off as it needs. Being in Brisbane I'd seriously consider a cab switch to trigger the thermos - by having them on when you've told them to be you can let the thermostat do all the work and not worry about the radiator's airflow. I did my switch by intercepting the factory thermo fan's wiring. I don't have the wiring diagram on the net but I'll endevour to get it sorted next week. Works a treat.

Hope this essay is some help!

Cheers

Bennie

[steptoe]

I reckon 91 92 C is getting towards too hot and like to see 77 to 81C as my op temp. Cruising on highway at 110 see 71 C a lot

Seriously, enginewatchdog.com is your friend in Brisbane . Got a mate hooked on them too 07 327 76770 Signals Aust in Salisbury 4107

[El_Freddo]

I reckon 91 92 C is getting towards too hot

I've had my EJ operating at about 115 degrees in the sand - I couldn't stop until I found a firm piece of ground.

The cooling system is under pressure, this increases the boiling point. With the help of the use of coolant running a little over 100 degrees shouldn't be a problem - for a short duration.

As for running near 90 degrees I wouldn't stress about this temp too much. I towed the camper with the temp on this for a few hours. Some hot days that's where the temp stays, right on the thermo kick in point. This is where my thermo fan cab switch comes into play - it allows me to control when the thermo is on as I've stated before. I think its the best way to go so long as you don't leave it in the OFF position - then you'll be in trouble.

Cheers

Bennie

[preno]

Does the key lie in purchasing a different thermo switch, and if so, what type? Tridon's website list the TFS 195 switch 90C to 85C. According to a Subaru manual I have sitting here the factory switch is from 95C to 91C. Does this mean a) the fans will come on earlier or b) the fans will run longer when they do actually come on?

a week back my thermo switch stopped working and so i replaced it with the tridon one. instead of the fan switching on at about 3/4 it now switches on at just under halfway. hope this helps.

cheers.

[phantomD]

a week back my thermo switch stopped working and so i replaced it with the tridon one. instead of the fan switching on at about 3/4 it now switches on at just under halfway. hope this helps.

cheers.

Yes it does! Can you tell me please the model number of the switch you used? Do you think it has helped the car to run overall much cooler?

[steptoe]

Go the tridon part number. I especially like the addition of manual switch as the switch cannot forecast the need to cool things before the event whereas you can , before mountain climbs, sand trips,hot heavy trafic etc. I too interested in what tridon one you fitted.

[preno]

it is the TFS 195 switch. it does run slightly cooler now due to the fact the thermo kicks in a bit sooner. im quite happy with it.