Better engine cooling

stilson

stilson

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Joined
Dec 27, 2011
Messages
1,790
Location
Sunny Balga WA
On our recent trip in the sand all 3 cars experienced very high (indicated) engine temps.

Scenario: hot day, very soft sand, uphill, AC on.

RedXS went over the red
The Grey Fox went just over 3/4
Blanket over 2/3

Turning the AC off brought temp down a little but this isn't an option for me when I have the Commander in the car with me.

What are the options for better cooling?
 
There are a few things:

do any of the vehicles have an aftermarket bullbar? if so, consider putting holes in it. (see my build thread and also dellsfoz)
Oil cooler?
bonnet spacers?
additional venting holes in bashplate?
some turbos have intercooler sprays: consider hooking up a second washer bottle to spray water into the grille of your car.
remove the bonnet blanket: that is the cloth thing under your bonnet. All it does is reduce a bit of noise, but it also holds heat in.
consider putting bonnet vents in.

In extreme conditions, shut down the airconditioner, open the windows and run the heater. It operates as a kind of auxiliary radiator. yes, you'll get hot, but no hotter than outside, and at least you won't cook your motor.
 
Really Stilson? I have never had issues even on 45degree days in hot sand.
What coolant are you all running? I only use Subaru genuine coolant. It's not mixture with distilled water either.
I found that when I previously ran cheaper coolant It would run hotter through the sand. Now the temp gauge never moves.
I was out at the pines with Hydrowill the other week and was really giving it hell with the ac on while it was hot and the two gauge didn't even move.
You could always upgrade to a larger radiator.

Dulagarl, my TJM bar has 3 large fins at the bottom of it that flow the air straight into condenser and radiator.
 
taza said:
Dulagarl, my TJM bar has 3 large fins at the bottom of it that flow the air straight into condenser and radiator.
Click to expand...

would be nice to see a close up pic
 
I'm with Taza on this. There is something a bit odd about it.

With Roo1, I drove to Brissy and back in 2011 in mostly 38-45C with the air-con on all but about a day and a bits travelling time. I had a pretty full load both going and coming. Took 3 days up and 6 back. The temperature guage never shifted off normal (in the middle of the gauge for it).

Roo2 hasn't been subjected to these sorts of temperatures for any extended period, but it never shifts off the lower quarter of the normal range (Don't you all hate uncalibrated gauges? I do ... ).

SWMBO's SH never moves off its normal position either.

Now I do understand that what you were doing is more akin to stop:start traffic than to highway cruising, but even so, I've never had any problem with over heating with any Japanese made or designed car I've ever owned or driven. Don't ask about the British cars though ...

I'm also under no illusions as to whether my fans are working! Even if I couldn't hear them, the whole car vibrates softly when they switch on ...
 
I have only over heated once, but that was only because I bumped my fans switch, so that doesn't / shouldn't really count.

There was one occasion about this time last year when I noticed my temp gauge did start to rise.
Admittedly it was one of our hottest days on record though at 45.7C (114 F)

But in saying that the temp gauge only rose a touch, from it's normal reading to about the 1/2 way mark or so.

Regards
Mr Turbo
 
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RB, driving on sand is different. Very slow car speed so airflow through the radiator is low with the engine working hard. It pushes the cooling system hard. When we were in Robe, Bennie had a prob overheating & Venoms was high but not overheating, but mine & Pezimm's were fine. I even had the A/c on in a few spots.

Apart from
 
In my experience the temperature gauge is not accurate. I have experienced engine coolant temperatures (ECT) measured through the aftermarket ecu of up to 110 degrees Celsius, and the temp gauge was at the same level when the ECT was 97 degrees. My fans are set to come on at 97 and go off at 92.

To get a true measure use a scan gauge or similar. If I relied only on the oem gauge I would have cooked my motor by now.

as Stilson experienced, factors such as air temp, use of a/c impact on ECT. Even greater impact is the engine working hard, which it does in sand, and going uphill. I have in the past had to stop, face the car into the wind and pop the bonnet until the fan cuts out. This has been when air temp is > 35 degrees and I was driving on sand for sustained periods.

there is absolutely no harm in improving airflow through the engine bay, and using a thermostatically controlled sandwich plate to divert oil to an oil cooler at high temps. If those measures prove unnecessary, your fan will not come on as early, and will probably not run as long. These mods would also allow you to run the a/c in more extreme conditions.
 
RB, driving on sand is different. Very slow car speed so airflow through the radiator is low with the engine working hard. It pushes the cooling system hard. When we were in Robe, Bennie had a prob overheating & Venoms was high but not overheating, but mine & Pezimm's were fine. I even had the A/c on in a few spots.

Dulagarl said:
There are a few things:

do any of the vehicles have an aftermarket bullbar? if so, consider putting holes in it. (see my build thread and also dellsfoz)
Oil cooler?
bonnet spacers?
additional venting holes in bashplate?
some turbos have intercooler sprays: consider hooking up a second washer bottle to spray water into the grille of your car.
remove the bonnet blanket: that is the cloth thing under your bonnet. All it does is reduce a bit of noise, but it also holds heat in.
consider putting bonnet vents in.
Click to expand...

Also a 3 way fan switch is a good idea:
1) auto controlled by the ECU
2) always on for sand driving or hard slow long climbs in heat
3) always off for water crossings (incl some kind of warning light or buzzer so you dont forget it!

In extreme conditions, shut down the airconditioner, open the windows and run the heater. It operates as a kind of auxiliary radiator. yes, you'll get hot, but no hotter than outside, and at least you won't cook your motor.
Click to expand...
This works really well, but you'll cook lol :rotfl:

Dulagarl, my TJM bar has 3 large fins at the bottom of it that flow the air straight into condenser and radiator.
Click to expand...

Dulagarl said:
would be nice to see a close up pic
Click to expand...

+1

taza said:
Really Stilson? I have never had issues even on 45degree days in hot sand.
What coolant are you all running? I only use Subaru genuine coolant. It's not mixture with distilled water either.
I found that when I previously ran cheaper coolant It would run hotter through the sand. Now the temp gauge never moves.
Click to expand...

+1

Too many people I trust say dont use anything but genuine Subaru coolant. Yeah I know its expensive, but it only needs replacing every 2yrs...thats $35 per year, not much really
 
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It was my engine that went over the red, so today I checked the oil and it seemed fine, not burnt at all. Generally the engine seems to be running fine. So I think the temp gauge must have a decent safety margin. Are there any other things I should check?

I was going to try and test my radiator fans as well, I think it would be working as my engine did cool while I wasn't moving, but I don't remember hearing them,
Would just putting 12v straight to the motor be the best way of checking or does anyone have any better ideas?

But I think a major problem would be my diy sump gaurd has no air vents yet, so I think I'll cut some holes in them.
 
Gidday Red

Power out here.

Start engine.

Run until fans come on at idle and stationary.

Note temperature gauge reading.

When fans go off, note reading again.

Are readings reasonable?

From my Batphone
 
Red XS said:
I was going to try and test my radiator fans as well, I think it would be working as my engine did cool while I wasn't moving, but I don't remember hearing them,
Would just putting 12v straight to the motor be the best way of checking or does anyone have any better ideas?
Click to expand...

Simply start the engine & turn on the a/c. The fans should immediately come on :iconwink:
 
NachaLuva you legend!
Yes the radiator fans both came on as soon as the aircon came on!
I must have thought it was just aircon noise.
Its good to know that they are working properly.

So it looks like I'll be cutting airvents in the sump gaurd tomorrow and avoid sand driving on 40+degree days.
 
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That just lets you know the fans are working. To be sure they're coming on when they're meant to best to use RB's method, the temp sensor thingy that tells the ECU to switch on the fans may be buggered still.

Someone did a good write up of DIY bash plate vents, Basically drill 2 small hole about 100mm apart & elongate them to get a jigsaw in. Cut between them & at right angles for about 30mm to make a flap. Use a matching block of wood & hammer to bend the flap in.

Note: The flap must be facing forward so air flows through the radiator & out through the vents. Also to prevent sand, mud, etc coming up through them.

More work than cutting holes but much better IMO :iconwink:
 
I wonder what the oil temperatures are reaching in 40C+ temperatures in the Forester? The Sunday after Christmas I was driving in temperatures up to 46.5C near Goondiwindi in QLD in my Golf and I noticed its oil temp reading was sitting around 108C when in average temperatures its usually around 100C.
 
Thanks for the replies guys, Duala I do have a bar but it has bigger holes than the factory bumper, my skid plate has the flaps as per Nachas instruction, I run windows down no AC but need to have the option of AC with missus and kids in car (+ obligatory extra loading), have tried the rad sprayers, they don't work, don't like the raised rear of bonnet but may consider relief vents but best thing I can think of is an XT bonnet with an oil cooler in the mouth.

RB, the sand driving was often WOT with speed <35kph for minutes on end.
 
You can add washer jets too your radiator also. It will help get the aircon colder and allow the wind to bw cooler as it passes through the radiator.

Due to my left kit in sand I have ample clearance under the sump which would allow air to flowunder and through the car. Red XS would not of had this with the stock clearance as he would be sitting on the sand bottomed our most of the time. I know this as I know the pines extremely well.
 
Autos will usually overheat in heavy sand driving and it's usually because the AT fluid adds heat to the radiator. A proven solution is to install a large (or larger) trans cooler and completely bypass the radiator.
 
Would mounting a hood scoop from a turbo fozzy be helpfull on a n/a foz?

Or making other vents in the hood so that it's easier for the engine heat to escape?
 
stilson said:
Thanks for the replies guys, Duala I do have a bar but it has bigger holes than the factory bumper, my skid plate has the flaps as per Nachas instruction, I run windows down no AC but need to have the option of AC with missus and kids in car (+ obligatory extra loading), have tried the rad sprayers, they don't work, don't like the raised rear of bonnet but may consider relief vents but best thing I can think of is an XT bonnet with an oil cooler in the mouth.

RB, the sand driving was often WOT with speed <35kph for minutes on end.
Click to expand...

The XT bonnet with a cooler could be a good idea, BUT...

a scoop without anything under it is a bad idea in my opinion. I would encourage folks considering this to read up on how engine bays get cool. The basics are that air moves from high pressure to low pressure. The principle is to maximise air in and air out, but air in is best at the front of the engine bay.

This article provides a good explanation.

https://www.autospeed.com/cms/A_2159/article.html

This is because you want to maximise airflow through the radiator, and a scoop can be counterproductive in this regard. A reverse scoop is a different matter. It can act as a way of getting air out, and hence increase the air through the radiator. There is some debate about this...

https://www.iwsti.com/forums/gd-exterior/74243-reverse-hood-scoops-functional-not-5.html

the only other suggestion I have is to have a look at your radiator. Insects and crap can fill the fins and reduce the ability of the radiator to "radiate" heat. Getting the hose, taking the grille off and giving is a hose through (of course with tank water!) is a good job on a hot day.
 
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