Offroad-Express

Yes of course low ratio and low tyre pressures!

No running standard thermostat (drilled out), contacted Toyota for lower rated one and going to try go in to pick one up asap. Or could just take thermostat out during summer and put it back in for winter.

bronx89 wrote:Gday. Yes viscous fan fluid is topped up, radiator has been stripped and cleaned, engine has been flushed, thermostat has been replaced and drilled. The issue is the auto + the sand and big tyres= hot truck i think.

When you say radiator has been stripped and cleaned, what was actually done?
Unless it has been properly tested for flow and pressure, or has had the end tanks removed and cores rodded and cleaned, there could still be a problem.
A mate had overheating problems with his vehicle, I told him radiator.
But he had his mechanic check it out, replacing lot of bits along teh way like thermostat, temp senders etc and eventually engines overheated, blew head gasket so engine was rebuilt, but still had over heating problems.
Radiator was supposedly checked but problem was eventually traced back to the radiator and not enough flow because it was half blocked inside.
Cost him heaps and I had to resist that "I told you so" comment for at least 5 minutes .............

bronx89 wrote:Yes of course low ratio and low tyre pressures!

No running standard thermostat (drilled out), contacted Toyota for lower rated one and going to try go in to pick one up asap. Or could just take thermostat out during summer and put it back in for winter.

If you take thermostat out it will run hotter as the water wont have a chance to cool down in radiator...i suspect you drilling holes in your existing one will do the same.
71 degree toyota part number 90916-03121

tallsam66 wrote:

bronx89 wrote:Yes of course low ratio and low tyre pressures!

No running standard thermostat (drilled out), contacted Toyota for lower rated one and going to try go in to pick one up asap. Or could just take thermostat out during summer and put it back in for winter.

If you take thermostat out it will run hotter as the water wont have a chance to cool down in radiator...i suspect you drilling holes in your existing one will do the same.
71 degree toyota part number 90916-03121

I agree the flow rate of the coolant thru the rad is critical, drilling the thermotsat should not be needed and Im my mind will only cause problems, idealy no modifications at all should be needed. there has to be something thats not right. the way I look at it is (and this is the way I look at it if anyone has a diferent opinion thats fine) manufactures build vehicles to not have any problems from factory and the test them extensivly to make shure they work as they should, so by modifying things like thermostats your only undoing all the manufacturesr R and D therefore inviting things to go wrong.... if that makes any sence to anyone.

does anyone else on here with a similar truck have or had the same problems.

also just to be clear when you say its getting hot. how hot is hot? like all the way to the top of the guage or 3/4 or just above half?

another thing to check is the outside of the radiator and the ac condensor is not blocked up with mud/sand and crap like that preventing the air from getting thru. Ive experienced evin having a wrong rad cap on can affect running temp by having the wrong pressure rating.

shurly the cooling system should easily stand up to bigger tyres, low pressures and being an auto. In my mind none of this should be a issue for the cooling system?... duno anyone else had this issue before, im intregued now as to why your truck is overheating.

Yes radiator had tanks removed and was fully cleaned and pressure and flow tested. It doesnt overheat on the road, it runs coooooold as. It overheats on the sand or going up long steep hills, well it id probably not even overheating but to me it is running hot (i.e. gets to about 95-100'c) so that is when I pull over and let it cool down for a while, or if the hill stops it cools down on its own quite well, it is the sand that is/was the issue, i am yet to test whether my new huge trans cooler fixes this and will let the engine run cooler.

No rad is not blocked up with anything, everything gets cleaned immaculately after a beach or offroad run.

Standard temp gauge never goes above half, it is my aftermarket gauge i rely on.

The major issue was the AT Oil Temp light coming on on the sand. This got me thinking is the engine coolant heating up the trans oil or the other waynround. Hence my mission to get the engine running as cool as poss and the trans running as cool as poss and not letting the two fluids cool/heat one another.

The holes in the thermostat are not big enough to prevent the coolant from having time to cool down in the radiator and i have noticed a drop in temp of about 2 to 3'c from doing this oddly enough!

Thanks for the 71'c part number going to get one asap!!

My rad actually leaks a tiny bit of coolant (and i mean tiny) from the top tank as i am guessing it was not sealed on properly after being taken off, it also looks a bit old and tired so now that i have no need for the in-rad trans cooler i am thinking about looking for a mint cond manual rad - they bolt up to the same mounts right?

Where on the engine does your aftermarket temp sensor take it reading from?

assuming temps being read from a good place, 100c is not what i would call to hot. certainly on the warm side but thats expected in sand etc.

have a look through the surf forums, these problems are common and theres a ton of fixes.

the drilling of the thermostat is just to put a small hole through to allow hot water to heat up the other side of the thermostat. ie stop the cold side if it keeping it cool and delaying the thermostat from opening.

Yep hence why i drilled it. Temp is getting read from the hot side of the radiator, no point on the other.

I know 100 isn't oh shits gonna break hot, but it is getting to the tempwhere you wana back off, isn't it?

A tonne of fixes? I have looked all over the net and done almost everything possible to try help it run cooler without spending more than the truck is worth. What tonne of fixes are you talking about? If there were that many fixes no one would have overheating trucks!

i think you need to be over 120c for it to boil.
but with their head cracking problems 110c would be safer. 100 is up there and may be considered max if its putting out a lot more power than standard.
in standard form i would be worried at 110c rather than 100c.

if you really want to get engine temp down (and this is so often overlooked) cool the oil and run a thinner oil.

theres the bigger things like intercooler, exhaust, air filter and housing, radiator cowling, the packers around the air con radiator, air flow directors around the sides of the radiator, bigger front bash plate, improving airflow past the motor and under the vehicle, bonnet vents, removing front spot lights and bull bars, trimming grill, increasing boost, removing intake restriction, injectors, fuel temp, alter timing........ the list goes on!

bronx89 wrote: It doesnt overheat on the road, it runs coooooold as. It overheats on the sand or going up long steep hills, well it id probably not even overheating but to me it is running hot (i.e. gets to about 95-100'c)

it all sounds pretty normal to me mate, i'd be suprised if it didnt get a bit hotter bogged down trying to push its way up a beach in soft sand or grinding up long steep hills?

Yep but even on the hard stuff cruising at 80-100kmph it still creeps up to 100 in RWD, thats where i thought it was odd getting that hot. And before all these cooling upgrades it shot up to 100 quick as as soon as i went for a play in the soft stuff.

Will see how i go next time, hope e things ive done will make a decent difference, and frickin hope the AT Oil Temp light has buggered off for good now too.

aftermarket air to oil cooler for the trans mate, cheep as and simple to install, fitted heaps of em to falcon utes etc over in aus with great results and eliminates any problem of the heat transfer inside the radiator leaking and stuffing everything with milkshake coolant as i call it.....
Just disconect trans cooler lines and re route thru cooler. idealy block up the ports for the heat transfer in rad just to stop sea water getting in there and starting corosion etc.

I would personaly trust the factory temp guage and sensor before I trust an aftermarket one. half way is mint and 3/4 is when ya realy start to look for somewhere to stop.

so anyway sorry if this thread has gone abit off the topic you origionaly posted on. but sounds like your prity sorted now being able to utalise the extra fan when you want. will be good to know if it helps keep things cool.

Just one last sily question. Is your fan shroud still in place around the viscus fan?

ladeda wrote:aftermarket air to oil cooler for the trans mate, cheep as and simple to install, fitted heaps of em to falcon utes etc over in aus with great results and eliminates any problem of the heat transfer inside the radiator leaking and stuffing everything with milkshake coolant as i call it.....
Just disconect trans cooler lines and re route thru cooler. idealy block up the ports for the heat transfer in rad just to stop sea water getting in there and starting corosion etc.

I would personaly trust the factory temp guage and sensor before I trust an aftermarket one. half way is mint and 3/4 is when ya realy start to look for somewhere to stop.

so anyway sorry if this thread has gone abit off the topic you origionaly posted on. but sounds like your prity sorted now being able to utalise the extra fan when you want. will be good to know if it helps keep things cool.

Just one last sily question. Is your fan shroud still in place around the viscus fan?

Gidday. Yep have recently installed a big Davies Craig 8cyl oil cooler running it on its own and have joined the in-rad factory cooler inlet and outlet on the rad (as well as flushing it out incase it does ever crack).

Trust the factory water temp gauge? Heeeeell no ill never trust one again lol. Plus they have some lil gizmo in there to make them prefer to sit at half even if they are really quite a bit lower or higher in temp.

Yea looking forward to seeing how she goes on the beach now especially with oil cooler and elec fan on constantly. Yep fan shroud definitely still in there no way i would take it out!! I know how much difference they make!

Cheers mate

yeah never ever trust toyota idiot gauges. by the time its shows its hot the engine has melted! you can mod them to get rid of the idiot spot but aftermarket can give you real numbers to work with.

haha well there we go I learnt something today.
don't trust a toyotas factory temp guage

Not sure if you have an egt gauge, if ya don't fit one, then drive by it and then see if you still have the problem, could be chasing ya tail and its all caused by driving style... As its been said before high egt (foot up it) more load on the motor which is more heat produced.

Definitely isnt driving style, and nope dont have an egt gauge but yes going to out one in as soon as i get time as fitting the sensor sounds like a bit of a mish.

With the 3 main cooling mods I have done it now runs 70-75'C on the road and 80-90'C offroad pushing it haard even on the soft stuff. Stoked.

So did you get the air con fan to start and stop on a switch.How did you end up doing it.

Not independently, but yes a switch allows and cuts power to the fan.

So when offroad just have to have the air-con switch ON and the new switch ON, this disables the air-con but lets the fan run at full power - makes a noticeable difference for sure!