Outer Limits 4x4 Board

I've been having a few poblems keeping the auto cool in my GQ.
I replaced the original cooler


With this Craig Davis larger unit (almost 4 times bigger)


...and bypassed the radiator to stop the engine also getting hot.

Did a Paj Challenge pratise this weekend and found it often getting upto 110-120 deg on long climbs.

Any suggestions on what else to do.

Alos the engine was still getting hot. Will replace the fan clutch this week to see if that helps.

have you had the auto serviced yet?

I'm booking it in this week.
Probably will go to Cavendish Autos in Dandy.
Haven't got the time to get across to Bayswater..

GUJohnno wrote:
...and bypassed the radiator to stop the engine also getting hot.

Did a Paj Challenge pratise this weekend and found it often getting upto 110-120 deg on long climbs.

Any suggestions on what else to do.

Alos the engine was still getting hot. Will replace the fan clutch this week to see if that helps.

Don't bypass any tranmision cooler in the radiator. they are suprisingly effiecent and any replacement needs to be huge to get the same cooling. your replacement is not very big.

also the cooler in the radiator can help with the tranmission getting to cold.

just as k the 3lt surf guys about transmission coolers

you cant by pass the radiator cooler as they remove 10 times the heat of after market cooler these coolers are designed to supplement the radiator cooler not replace it

Fill up your hub with a tube of new silicon oil from Toyota.

Did mine on the w/e and it didnt even reach 1/2 in the 42 degrees on sunday with a/c on!!

rvh96 wrote:you cant by pass the radiator cooler as they remove 10 times the heat of after market cooler these coolers are designed to supplement the radiator cooler not replace it

Andrew when he built his alloy radiator didnt built in tanks for the auto (Petrol 4.2), and the car now runs so much cooler, and the tranny is the same.

bogged wrote:

rvh96 wrote:you cant by pass the radiator cooler as they remove 10 times the heat of after market cooler these coolers are designed to supplement the radiator cooler not replace it

Andrew when he built his alloy radiator didnt built in tanks for the auto (Petrol 4.2), and the car now runs so much cooler, and the tranny is the same.

the operating temp of a transmission is over 200 degree's

the operating temperature of teh engine is about 100

if you pull the cooler lines out of the transmission you are asking for trouble.

what you need to do is run the cooler inline with the radiator tank, but only use the tank 1 side of a crossflow radiator ( patrol is crossflow) on the hot side.

running before or after the radiator is the question.... only to be answered by a temp sender and guage in the transmission.


Jes

jessie928 wrote:

bogged wrote:

rvh96 wrote:you cant by pass the radiator cooler as they remove 10 times the heat of after market cooler these coolers are designed to supplement the radiator cooler not replace it

Andrew when he built his alloy radiator didnt built in tanks for the auto (Petrol 4.2), and the car now runs so much cooler, and the tranny is the same.

the operating temp of a transmission is over 200 degree's

the operating temperature of teh engine is about 100

if you pull the cooler lines out of the transmission you are asking for trouble.

what you need to do is run the cooler inline with the radiator tank, but only use the tank 1 side of a crossflow radiator ( patrol is crossflow) on the hot side.

running before or after the radiator is the question.... only to be answered by a temp sender and guage in the transmission.


Jes

http://www.outerlimits4x4.com/viewtopic ... t=radiator


The main reason I made it is that on slow speed low range and even highway work on the hills the temp gets up there. As soon as I back off the temp falls but I wanted something that just wouldn't get hot and it fitted the bill perfectly. Also the wife and I are buying a caravan and we want the cooling system in top order.
The main problem appears to be from the auto trans coolers in both endtanks radiating heat into the coolant. Easy solution I hear you say, remove them and use an external one. Well, that doesn't quite work as well as it could because the auto needs to run at an optimum temp and not too cold. If it's too cold then the torque convertor lock up won't work.
The best method is to use both radiator endtank trans coolers and an external on as well and that's what I've done.
As far as toughness is concerned, nearly all 4x4 radiators are now aluminium but they use plastic tanks and you'll get approx 4 to 5 years then the tanks will have to be replaced.
But, for cooling ability, aluminium beats brass ones hands down. Have a look at any current Commodore V6 the radiator would be lucky to be 20mm thick and if the system is in good order they have no problems.
I'll be mounting it using original mounts and original fan and shroud assembly as I'm not in favour of electric fans for a 4x4.
I've made provision for 2 extra temp senders, one as the coolant enters the rad' and one as it exits the rad so I can get some accurate differential temps under different ambient and road conditions.
My next project is an intercooler for a turbo/petrol 4 cylinder Jackaroo using a blow through carby setup and a custom aluminium radiator to suit an FJ Holden with a red motor in it.
No rest for the wicked I guess.
Regards Andrew.

Bruce, I have since changed my mind on that post which is probably a couple or more years old now.
I now run 2 front mount coolers only and none through the radiator. The OEM ones in the radiator were simply placed there because they're cheap and compared to the front mount ones they aren't as good full stop.
My auto temps are on average 50-65 C, on Sunday when the ambient air was 40C my auto temp was 60. When towing my caravan, on one particular hill the temps got up 85C (ambient air about 22C) still waaaaay below what it used to run with the radiator cooler and one front mount cooler. When we were on the flat towing the van in 3rd with the torque convertor manually locked the temps went back to 50C and that's towing 1.6- 1.8 tonnes.
Regards Andrew.

Johnno, you have gone down the right track in removing it from the radiator. Perhaps do as I have and get another auto cooler on the other side and run them in series from one to the other and then back to the auto. On my 92 GQ Ti it has a front mounted air con pusher fan and I've mounted one cooler between the fan and the air con condensor and at some stage I'll wire it up manually so when 4x4ing I can turn it on so it always has air flowing over it even when in low range.
With one cooler and no radiator cooler my normal running temps on the road at 100 Kmh were around 70-75. With 2 front mount coolers it is now 50 or even less.
Regards Andrew.

You've all forgotten one important thing. The passageways in the factory trans cooler are too small so particals that wear off the torque convertor linings will block the trasn cooler. This is what causes the total trans meltdown that costs so much to repair. Yeah the factory ones may be effiecient but once the trans is 200k old the linings are coming apart pretty quickly so expect a failure unless you have bypasses the factory cooler. Bypassing it has nothing to do with improving cooling it is a precaution against spending $4 to $5k on a rebuild.
I got mine rebuild and upgraded last year and the total cost was under $3k as they only needed to replace clutches etc. With the amount of shit in the filter, the oil flow through the cooler would have been stopped causing the entire gearset to be unlubricated.
I'm just about to get mine stripped again (this week) so that it can have the shafts changed to fit the VH45, so I'll be able to see how it has handled my old TD42 with 21psi, intercooled etc etc. for 12 months hard work.

nzdarin wrote:You've all forgotten one important thing. The passageways in the factory trans cooler are too small so particals that wear off the torque convertor linings will block the trasn cooler. This is what causes the total trans meltdown that costs so much to repair.

happened to an old bloke in our club with a TB42, towing his trailer lost all forward drive, but if I remember had reverse...
$4000 later new box, and the works from Wholesale autos.

Good replies... Thanks!

nzdarin: The tranny place I went to said the same thing. They have had to do re-builds because of this.

They said by by-passing the radiator and adding one cooler, I have taken a small step forward.

They suggested to add another cooler and keep them as close to the aircon condensor as possible so that the fan draws the air through. At the moment there is a large space in between and the air can easily go around.

I'm it the process of mounting my trans cooler on the tray with it's own cooling fan. A lot easier to do these things with a dedicated toy that doesn't need to be pracitical

Installed anther cooler tonight. Took a while as I had to make extra brackets. They're nice and close to the condensor. Also I have booked it in for a service.
I'll give it a good testing at Mt. Dissa on sunday.

tranny fulid enters intop the rad and the heat is taken away from the fulid then goes back up to the tranny

if its still to hot why not run a aftermarket cooler before it runs into the factory tranny cooler

will work better subcool the fulid before it enters the rad for more coolin hey why not go nuts and wack a thermo on it also problem solved


why people go for the aftermarket item souly on their own if you can use aftermarket and factory cooling setups go for it

There is also one other reason to bypass the factory cooler, if it breaks internally inside the radiator, I have seen them do this, your trans is instantly toast, coolant will get into the trans and it only takes about a teaspoon of water to destroy an automatic trans.

Cheers, Jeff.

I gave it a good testing the other week.
Most of the time it's staying nice and cool.
Only managed to get it warm on a long climb, but as soon as I dropped it back a gear it cooled down straight away. So all is good!
One less thing to worry about.