Hilux 1UZFE cooling questions

[Mattmannz]

My LN130 has a large aftermarket radiator with the two factory electric fans pushing through it.

Normally the truck runs at about 87-90 degress depending on whats happening however over the weekend doing a big sand run the motor got to 110 and didn't want to cool down.

I ran with the heater on full hot to keep it at 110 and after stopping it took about 10 minutes with the bonnet up idling to get it back down again.

It was only the sand that seemed to upset it and it wasn't that hard work either.

What are most people running cooling wise? Are the factory AC fans good enough?

Cheers
Matt.

 

[Guts]

Sand works em hard, a lot harder then you think.

I used to run twin 10 inch thermos on a stadard rad and it worked perfect for all driving untill it was working hard going slow, then it`d heat up quick.

Now I run a GQ Patrol rad behind the cab and use the twin ford falcon thermos and shroud, it almost cools to much now.

 

[Mattmannz]

Thanks Guts.


We weren't running that slow, I was in fourth gear in low range pulling low to medium revs.

I will measure my rad on the weekend and post the specs here to compare with others.

Cheers
Matt.

 

[hi-lex]

I still think airflow is the main culprit, after much kenoodling we finally got the black lux sorted , the owner put big flaps between chassis an inner guard, so I cut them down to give 3" gap, relocate lic plate to expose winch hole and made a neat deflecter at crossmember-radiater to get the flow thu rad an help push it out eng bay

 

[sideshow]

more airflow might not help all the time

my 1uz hilux on the highway does not drop in temp

my old thermostat had few holes drilled in it so had bit more water flow thru it
new std thermnostat keeps temp steady on highway
so if i hop on highway at 85 it stays around 85 even when i drive at 130 kph

so i think water flow at above idle revs has alot to do with it

i now run a std tridon 82 degree thermostat and on highway temp is steady
thats because revs are about 3000 and water flow is ok

when i run my extra holed 71 degree trd thermostat the temp will drop to 79 on the highway

so i might go back to it when summer hits

if the revs are above 3000 for prolonged time
maybe just try drilling 4 or 5 three or four mm holes round outside of thermostat
this will give bit better flow when revs are above 3000

 

[Shuey]

My solution, so far has been to loose the aircon condenser, cut a hole in the bull bar and relocate the number plate to allow air flow through the radiator and fit twin 10" thermo fans behind the radiator (draw through) Finally, install a couple of "Moffat" bonnet vents to relieve the heat from under the bonnet.

A couple of cooling experts over here in the West have done quite a bit of testing on this issue (with similar cars) and found that you only need a small pressure differential between the air pressure at the front of the car/radiator versus the under bonnet pressure (hotter air) to cause a lack of flow.

I've seen guys "shim" up their bonnets at the hinges with some success.

Mine runs fine in the rocks and hills, but the beach and soft sand stuff where the motor is under constant load is an issue, but my mods to date have definitely improved things.

Next step for me is aluminium 2 core radiator that is wider than stock, but shorter in height, then use a fan setup that can draw air accross the full surface of the radiator (shroud). I'm thinking that this should do the job better.

Thats my two bobs worth...

Cheers,

Shuey

 

[hi-lex]

I reakon your right, the missus's car Im doin at the mo is gunna have a 2 row alloy rad ($390 delivrd off ebay US) and some kinda scoop, should sort it, bigger rad is just delaying the inevitable but isnt it or buying time til the load is reduced

 

[Guts]

I had/have no ac, a tube bar and no driving lights on the front, no flaps down the sides of the engine bay to the top of the rails, the rear of bonnett spaced up with the rubber seal removed, twin 10 inch fans that covered the full width and most of the hight of the rad, no battery which makes for an allmost empty engine bay.

Wheather I was doing city driving or highway driving towing a trailer on a 42 deg cel day (new years day this year) it never got hot, it never got over about 92 deg cel. But if I was 4x4ing going up long steep hills in 1st low at 1000rpm or long wet clay hills in 1st or 2nd high at 7000rpm it would get hot in about 5mins and by hot I mean 110 to 115 deg cel. Once I`d stop and just let it idol it would drop back to 90 over about 5 mins.

With the new setup if I leave the fans on I can get it to drop to 70 deg while I am working it hard at 6000 to 7000 rpm.

I only a few weeks ago did a 4x4 comp with it and this event had 2 15hr long legs of hard 4x4ing. For most of this it was working hard. To the tune of using approx 35lts of fuel per 100kms of driving.

With the new setup behind the cab I get NO airflow even out on the highway at 110km/hr all the cooling is done via the fans.
The water capacity has gone from approx 5lts of fluid up to a wapping 12lts.
I`m also still only running the standard water pump.

If I still had the rad in the front I would have tried a triple flow rad and added a water tank in the system to add extra volume before anything else.

I think one of the biggest things with the 1uz in a hilux is the cooling system only holds approx 5lts of fluid, I think its under that infact.

 

[Mattmannz]

Thanks for all the info guys.

My truck seems similar, no vents or anything and it always sits on 87-90c no matter what I am doing except when I put it on the sand and then it gets real hot.

I think I might flush the rad this weekend and check out the capacity of the radiator.

Cheers
Matt.

 

[twisty_toy94]

Originally I used the std. V6 radiator in my 4runner, with 35mm hoses, and two mitred joints off the radiator. I didn't have a proper water temp gauge while running this but it seemed to keep it cool judging by the factory gauge. But since installing a proper water temp gauge and comparing this to the guage on the dash, it had deffintly been running hot at times.

I'm now running a core out of a later model surf, which is just over 2 inches taller than the standard core, and has better header tanks (more square to hold more volume) and am running 38mm hoses and smooth rubber bends. (No mitired joints as pictured on the old radiator). With a 16" ICE themo fan pushing from the front and running continuesly (will sort that out one day) and no AC Condensor, it sits on 80-85 degrees for all driving around town and on the highway. On a couple of long steep ranges I've done I got it up to 95, and in the sand, the hottest I've got it to was 100......

I'm also running a forward facing patrol bonnet scoop.

 

[neal]

It may sound silly but make sure radiator is plumbed the right way. When I put mine in cruiser I put hose from thermostat housing to top of radiator as most engines are plumbed. but found out that this should go to the bottom of the rad.

 

[sideshow]

i fitted my 71 degree thermostat with the extra holes drilled back into my system yesterday

runs much cooler below 80 all the time unless i stop for 5 mins

another thing to check on alloy rads

i have 0.5 volts running thru the coolant and it ate abit of the rad and i had a leak

i totally drained coolant as best as i could thru drain holes on block

then i filled system with demineralised water

now i have 0.25 volts so in afew weeks ill flush system with demineralised water again

so its a good thing to check if u fit an alloy rad

if i disconnect battery i still had 0.17 volts running thru the coolant

 

[hi-lex]

you need to esure the rad is earthed to the motor then, this is a common prob on late model cars ,if its equipotential bonded there shouldnt be a voltage diff

 

[sideshow]

the rad has 4 bolts holding it to body
then i fitted 4 major earths on engine and auto
still didnt fix it

voltage from rad to engine and rad to neg terminal was 0volts

so at moment most of it is due to bad coolant and water

 

[1uzvl]

more often then not if you have a electolysis problem earthing the rad via a wire dirrectly to the battery will increase the problem and have done this many times.We use 0.05volts as a maximum on all ally rads but copper/brass is not such a problem.

 

[sideshow]

ok i dont have any wires on rad

what is best way to get rid of electrolysis

i have read u should use an analog multimeter but i only have a digital one
is it ok to use a digital meter to test it
its a fluke meter so its good one

 

[1uzvl]

we were also told to use analog meters aswell but no-one could tells us the difference so we just use a digital.Im not a sparky but it all comes back to a bad earth in your electrical system so clean ALL earths(dash,lights,fans etc)should fix the prob.You can try to narrow down where it is by turning on circuits one at a time but make sure the t/stat is open.Also new coolant will produce current for a few days and then will settle down so test on a system with only demineralized water if possible.Other than that we send it to a sparky.See how ya go.

 

[sideshow]

yer im goin to run dem ineralised water for abit and recheck

weird thing is with battery disconnected it has 0.17 volts

just shows how bad some coolants can be

 

[gloverman]

Hiace Cooling

Hello

The cooling system was something I thought about alot while planning my conversion into my hiace. We ended up with two radiators. One standard upright radiator and a turbo diesel radiator lying flat at the front of the van with the a/c radiator attached to that. We fitted a 14inch fan to the upright radiator and the factory turbo diesel fan on the lower radiator (the a/c and front fan are yet to be connected) I fitted a 68degree aftermarket performance thermostat.
The total volume is around 14 litres. Airflow past the motor is quite limited as the headers are about 20mm off the torsion bars with the inner guards 20mm behind that. I am still using a standard 0.9 bar (13psi) cap.
On a frosty morning the van gets to running temp in around 1.5-2 km of driving and sits at 72-73 degrees at 100km/h driving. On a normal day 100km/h driving results in about 78 degrees. Around town with stop/start condition it sits just below the fan switching temp - 92degrees. I also have a rev limit of 2000 rpm if the temperature gets to 120degrees.
Another intersesting point is sitting in the workshop on a warmish day 20-22degrees I will watch the watertemp get to 92-93 with the little fan going an the air temp rises from 20(normal running) to well over 40degrees. That is with the air temp sensor in the airbox(standard position for a van) which proves that these motors do suffer from heat sink.
My recommendation is lots of volume in the cooling system, top grade coolant and the biggest fans that will fit to get plenty of air flow at low speeds/high loads. I will definately be getting my second fan wired before summer rolls around and may move my air temp(or fit a second one) to the
manifold to see how hot it gets in there.

Good luck keeping yours cool
Cheers
Kelvin

 

[-Nemesis-]

I eventually managed to squeeze a radiator out of a FZJ75 Landcruiser into my 4Runner. The core height and width (front on) is the same, but it's a massive 65mm 4 core, and the header tanks are huge. I was a bit worried about it being too thick but it seems to be really good. I chased a commodore up the Moonbi ranges flat out in 3rd (you can't find a longer steep hill) and it didn't go over 91 deg. With the original 4Runner radiator it sat on about 95 on the freeway and went over 100 on the first sign of a hill.

This is the radiator type here, check out the price for a brand new in the box radiator (versus a $1000 custom jobby)

http://cgi.ebay.com.au/TOYOTA-LANDCRUISER-HZJ75-1985-98-4-ROW-MAN-RADIATOR_W0QQitemZ120007153615QQihZ002QQcategoryZ10428QQrdZ1QQcmdZViewItem

Thats with a 16" thermo on the outside. I'm about to put it inside and put the A/C condensor back in to see how it goes, cos 'she' wants the A/C back on....

You can sorta see how much taller the radiator appears thanks to the big header tanks.:

Here's my truck for reference :bigeyes: