Outer Limits 4x4 Board

Here is a question for the V8 Patrol owners - how do you keep them from overheating? I have serious underbonnet temperature problems as well as the radiator boiling after a normal drive... The radiator that I used is from a 3L GQ with dual thermofans (are all the GQ radiators the same?) but I think I need bigger. Does anybody know of a suplier of big radiators?

I have attached the photo of the engine too - might give you an idea of the problem!

Aussie Desert Coolers are ya friends for a new radiator !... a 4 core will help improve things dramaticly.

I've tried several different cooling systems and to date NOTHING beats an engine driven fan regardless of room under the bonnet and from the pic I'd say there's not a hell of alot of that to spare.
The twin thermo setup works ok but is in trouble once speeds are over 80/90kph, and yes I have tried 4 thermos to counter that ( it failed too ), I tried twins on the front and a 16" on the rear of the radiator ( it also failed ). I now run a 16" on the front with the aircon condensor removed and a std nissan engine fan converted to the chev waterpump ( see below pic), .... it never gets past 95 degrees even when its a heatwave outside!

From ya pic I'd hazzard a guess and say that 70% of the problem is more the abillity to get rid of the air once its passed through the radiator... simply put... where the hell can it go???
The WB Statesman ( from holden) had a similar problem when first released, they knew it from factory but did a wait n see thing. Cars that were sold in the cooler climates of Aussie didnt have a problem but the few that went to hotter places did. They later solved it quite simply by adding an airdam. The airdam sits under the radiator and is as wide as the chassis members, it then runs towards the sump to a distance of 250mm with a slight kink down in the last 30mm. The effect of this airdam is exactly the same as a venturie, it creates a vacum under the motor and drafts the air into that area. I made mine from a plastic "wheelie bin"

things to try...
take the bonnet off and go for a drive.
This opens up any/all airflow restrictions. If it cools the motor maybe a bonnet scoup might be a fix it, The A9X scoup is a good one to use, once you've assessed the working of the bonnet scoup a custom one could be made to improve the looks of your rig. ( I added a pic of my ute for that reason )

try fitting an airdam
this will help with the airflow and an added bonus is it also directs water away when doing river crossings, and prevents mud etc from entering the enginebay

fit an engine fan
You will need to cowl the fan too for the best result but an improvement will be noticable without the cowl initally.

remove aircon condensor.
You can remount it elsewhere under the rig with a thermo on it.

fit a 4 core radiator
Big $$$ but a worthwile investment.

Conclusion....
The thermo fan moves air at a constant velocity, regardless of your speed while an engine fan increases the airflow as speed is increased.

The thremo fan does not have the "power" to force air away from the radiator once it has passed through the radiator, nor does it have the "power" to force the air out of the engine bay.... the engine fan does.

Under bonnet room is esential for airflow, a restricted engine bay has restricted airflow. Better drafting through "airdams" and/or "bonnet scoups" will aid in opening up restrictions. (Its one of the reasons why "custom rodders" using big block motors remove the inner guards)

Akso looks like the intercooler wont be helping the rad do its job. It will supply hot air and reduce airflow.
Block all bypasses around rad, fit cowl if you can.

Bazzle

bazzle wrote:Akso looks like the intercooler wont be helping the rad do its job. It will supply hot air and reduce airflow.
Block all bypasses around rad, fit cowl if you can.

Bazzle

THink Bazzle hit it on the head, the rad is totally coverd by intercooler... Hot air straight out of the Intercooler into the Radiator, it doesnt stand a chance..

Desert Cooler Radiator or Alloy one will help, but yea, twin Turbos, adn the IC where it is, ya askin a bit much!

so whats the specs on the motor setup?

is it late nissan v8 with twin turbo's?
or lexus?

whats it like?

With our previous GQ we fixed the overheating problem a few ways.

1. A 4 core radiator.
2. GU bonet scoops.
3. More oil in the clutch fan.

Our current turbo, intercooled petrol GQ ran on 3/4 on one of the navruns we did but that was a 40 degree day, so the below bonnet vent has now been fitted.

Drafty, did you face the GU scoops forwards (like factory) or backwards? I'm thinking about fitting them to mine and trying to decide which way to face them.

How big is your new vent, and where in the bonnet have you fitted it?

Thanks guys,

I tried blocking all of the sides of the cooler setup. It made it a little better but still not brilliant. I have already got the air dam underneath...

I have cut away the inner guards to try and ehaust the air (and so the suspension etc would fit) but there isn't enough airflow at speed. I will take the A/C condenser out and give that a go next... I have added another photo of the inner guard area and all of the restrictions!

The motor is a Infiniti VH45 with a twin turbo conversion. I am also running it on gas only just to make things more complex. I have kept the 4 speed auto which is similar to the Patrol auto, just with different electronics. I am not sure how much power it is putting out but I don't think the tyres are going to last long... The rest of the details are on my web site...

I am sure you have already thought of it, but anyways, looks great, that thing is spectacular. Take me for a drive. One thing, I am worried about your radiator fill cap and the height of your body lift! Except there is two caps. No fluid is leaking out of the lower cap? (the one on the hose??) Nick had a problem with his import motor after the body lift put the radiator above the cap on the radiator hose.

You are running a 1" or 22-25mm suspension drop correct? Coupled with a 2" body lift to fit your (roughly) 32" tyres? The top of the radiator could be above your fill cap. Hence less fluid than it should have. You need to relocate the cap to the highest point in your system, if this is the case. If not and the cap is at the highest point in your system, then bigger fans, or a bigger radiator is all you are limited too.

Again, it looks awesome, and I hope to see more pics of it out and about too... Unreal!!!

gu bonnet scoop backwards looks good as i have just done it too mine, and it gets rid of a lot of under bonnet heat

Nothing worse than a holden with ford bonnet scoops,shame shame.Or a nissan for that matter hahahahah.Great lookn machine,good luck with the beast.

junior wrote:Nothing worse than a holden with ford bonnet scoops,shame shame.Or a nissan for that matter hahahahah.Great lookn machine,good luck with the beast.

couldnt agree more ,,....... but it was done far a reason at the time. I needed to gain 4.5 inches above the std bonnet height to allow for the carby and manifold setup. An "A9X" bonnet scoup is only 4" and there wasnt anything availiable on the market at the time.
There were 3 bonnets used to "create" this bonnet and its still a one of, plenty of ppl did the ford scoups to holden thing but we added the holden centre to the ford shyte.

MKPatrolGuy wrote:Drafty, did you face the GU scoops forwards (like factory) or backwards? I'm thinking about fitting them to mine and trying to decide which way to face them.

How big is your new vent, and where in the bonnet have you fitted it?

Dave we had the scoop facing forward as at that stage it sat above the intercooler.

If you are trying to cool the engine bay then have the opening facing the windscreen.

New vent is about 600 by 300 and sits between the radiator and motor, idea is to let the hot air be pushed out of the engine bay by the fan as soon as it passes through the radiator.

Drafty wrote:New vent is about 600 by 300 and sits between the radiator and motor

SO you have made something up to direct the air from the radiator straight out of the wheel arch or the bonnet??

Sits in the bonnet just past the radiator.

Drafty wrote:Sits in the bonnet just past the radiator.

and creates a draft?

Has fins which run down and as the air is pushed out past the radiator it is directed up and out. Do l have to draw you a pic ?

Anyway we know it works

Drafty wrote:Has fins which run down and as the air is pushed out past the radiator it is directed up and out. Do l have to draw you a pic ?

Anyway we know it works

photos would be handy, I think it could become a common mod for GQs with Turbos...

hazard has moved the air-con shiat ti under neath the truck, and the auto cooler into the bullbar. I think he has just about got it sorted..

unreal!!

pics pics and more requests for pics!!