NewHilux.net

While there are many threads on Hilux's getting hot and air-conditioning cutting out etc. I have not been able to determine what workable options are out there to upgrade the engine cooling system for a Hilux D4D.

My issue is I have a 2008 Hilux Sr5 manual DC with 31 inch tyres. I tow a large camper trailer that weighs nearly 2 tones.

During this summer when pushing along at 100km/h my after market temp gauge shows my water temperature heading upward of 105 degrees on even slight hill climbs. Putting the boot into it to over take can also result in an aborted overtaking when the temps get too high.

At 103 the AC cuts out and does not come back on until the water temp gets back under 100 degrees C.

Also on hill climbs in third gear the temp just skyrockets and has hit 108 before I noticed and backed off.

With the wife and three young kids in the ute the AC going off gets a bit annoying and the only way to keep the ute cool is to back off. The ute has the power to keep pulling especially on hills but you can not use it because the cooling system does not let you.

Now I had replaced the fan clutch, thermostat and water pump before summer but the radiator I have not touched yet until I can work out my options. Yes the Fins on it and the AC condenser are clean with no mud grass seed etc.

I have seen comments that the Denso radiator is the best option for radiators but I want to be sure before I replace the existing one in case it is partially blocked. Even then I don't think this is going to improve things greatly. But I may be wrong.

I have read that people have tried electric fans but I am not convinced that this is the best path yet as I haven't heard any one has really proven that this improves the cooling.

So what are the options. Are there better radiators either aftermarket or from other vehicles that are head and shoulders above the OEM one? Or is there other things that can be done. such as high flow water pumps, thermostats etc.

Some more info. I have an ARB deluxe bar with round IPFs and warn winch. I also have the ARB bash plates. All these may be blocking some air flow but taking them off is not an option.

At the moment I have standard diff ratios and am preparing to change these to 3.9s in the hope that this will make towing better (Especially hill starts in first) and help with the cooling. But Still I would like a better cooling option as well.

So over to the community. While I may still have a cooling system problem that may be fixed with a new radiator I really want to know what can be done to upgrade the cooling system. From every thing I have read this is a problem with the Hilux's so surly there must be a well proven solution out there????

i dont know about proven options but you could try setting up a water mister infront of your radiator run off switch from the dash. you could do it fairly cheap with a washer motor and nozzles from the wreckers. When you see your temps coming up give it a bit of a squirt to drop them back down. otherwise have you flushed your radiator and block out?
electric fans probably wont help you much as they normally wont pull as much air as a working clutch fan and when your travelling at speed the fans dont do anything anyway

can you get low temp thermostats for the lux's thats what i put in my silvia keeps it much cooler cause the thermostat opens at a lower temp.. other than that id just replace the radator and or put a additional electric fan on a 12v switch and switch it on when you need it to assist the clutch fan

A lower temp thermostat will cost you dollars because the engine will run richer till it gets to operating temp. If it doesn't get there it will constantly run rich costing you money at the fuel pump.

The factory cooling system in your Hilux should be able to pull a 2 tone load with ease without overheating, provided the components are working to full efficiency.
Your symptoms suggest an inefficiency in the radiators ability to dissipate heat.
The first thing I would do is have the top tank pulled off your radiator to check for blockage. They do block up after 5-7 years of service.
If it's not blocked then the problem lies elsewhere. If it's blocked just put a new genuine Denso rad back in, the manual Denso rad should cost you no more than $260 plus fitting.

A lower temp thermostat won't help your symptoms. A thermostats job is to maintain a minimum running temperature, not maximum. By the time your car is at 100c the thermostat is already fully open and has been for some time.

I know the AC cut is a PITA but your engine is still safe at 108c, in fact with the correct coolant mix and factory pressure cap the cooling system won't boil until 127c.
People think that you can damage the engine at 100-130c......... No chance. While there is still coolant in the system it is impossible to damage any engine component, because while there coolant in the system the temp cannot be above 127c. Boil the coolant out.......that when shit gets dangerous, and temp climb real fast to 250c+ zone.

Temps need to be above 250c for any engine damage to occur, Annealing (softening the metal) is carried out in the range 300-410°C.
I'm not saying you don't have a problem, but don't be too worried when you see the temp hit 110c up a long hill, towing on a hot day. Your engine will be just fine.

Check that rad first.

Thanks Every one.

The idea of water misters had crossed my mind but the down sides make this impractical for me.

Thanks PRS your points are all understood. I have a price for a new Denso radiator of less than $200 dollars. I have also been quoted $180 to take the top off the existing one and clean it out and check for blockages. So getting a new radiator makes more sense.

I was really hopping that there was a larger capacity radiator out there that would give the cooling system more cooling head room. But I have not found one (Yet). This would have been ideal as no mucking around with helper fans, misters etc.

I think I will bite the bullet and get a replacement Denso radiator and see if that improves things. After all it is the only thing I have not replaced.

I have just been looking up the specifications for Denso radiators and have noticed that the unit for automatic gearbox Hilux's is 27 mm thick compare to the 16mm thick manual gearbox one .

I know that they have the auto gear box cooler built into them but would this unit cool better for the manual? They are only $60 dollars more and you could block off the gearbox cooling pipes. and I imagine they must have better cooling as they also need to cope with the heat load from the auto.

Has any one done this?

do you have spotties or anything else mounted on the front? They could be restricting airflow.

PRS wrote:If it's not blocked then the problem lies elsewhere. If it's blocked just put a new genuine Denso rad back in, the manual Denso rad should cost you no more than $260 plus fitting.

Err, I got a quote from Toyota dealer of somewhere between $800 & $1000 for a genuine manual one

Hi Moiv

I have been ringing around the Natrad guys Prices vary a little but one close to me quoted $170 plus freight for a Denso manual radiator.

Denso list change over units on their web site so I am going to go back and clarify if the price is for new or change over. It may be for a change over at that price.

scratcher wrote:do you have spotties or anything else mounted on the front? They could be restricting airflow.

Yes I do have spotties, bull bar etc. Check out my original post. But taking these off is not an option hence why i am looking for a better cooling solution to counter act these.

jplozza wrote:

scratcher wrote:do you have spotties or anything else mounted on the front? They could be restricting airflow.

Yes I do have spotties, bull bar etc. Check out my original post. But taking these off is not an option hence why i am looking for a better cooling solution to counter act these.

Take the lights off just as a test to see if it makes any difference ,,,

ktm300 wrote:

jplozza wrote:

scratcher wrote:do you have spotties or anything else mounted on the front? They could be restricting airflow.

Yes I do have spotties, bull bar etc. Check out my original post. But taking these off is not an option hence why i am looking for a better cooling solution to counter act these.

Take the lights off just as a test to see if it makes any difference ,,,

Thanks for the suggestion ktm300 but we are getting away from my original question and objective.

I am trying to find a better cooling system either larger radiator or the like. I am not trying to diagnose an over heating problem per say.

Taking the lights off may tell me that it cools better with out them. But then what? I will still put them back on and will be back where I started and that is there better ways to cool the lux?

My current line of thinking is that maybe the radiator from and automatic Hilux may give greater cooling capacity. So I am interested if any one has done this and is convinced it is better.

Most likely radiator or fan hub mate.
Done heaps of them ova hear

Why not take ktm300's advice and check without the lights fitted (can't be to bit a job to remove) and if the lights are a problem, relocate them cos whatever rad you fit it will still need plenty of airflow. At least this will test if the lights are a problem. Also, there is a thread on here about lightbars preventing flow over the intercooler by obstructing the flow into the bonnet intake. Lightbars thus will also obstruct the rad if that is where they are mounted.

I have a petrol 09 ggn25r. to say that i'm dissappointed with the a/c system in the lux is really an understatement, My wifes Mazda cx-5, however, has awesome, awesome ac. I eagerly await some credible path of investigation.
Having been inspired by this thread, i'll be saving for a scan guage II to test the ac effectiveness when the water temp is high/low.

I have seen truck, supplementiry AC units that are roof mounted, but you have to supply 24v.

Did you get this sorted? Try changing the coolant to a good one. Do a 50/50 mix or 60/40. The valvoline one is one of the best I have used. Could also be ur water pump on its way out aswell. Don't use more than 50% coolant, it can cause dramas and also make it harder for the water and coolant to cool down.

What about mounting a front mount inter cooler, wouldn't that lower the engine temperature, plus get a little more power for the same amount of fuel used?

The answer to this is pretty obvious. Your radiator is partially blocked. Either buy a new one or get your one recoed. Problem solved

I've been using the dealer to keep the coolant filled. Bad idea.
I took the hilux to a place in nunawading, they measured the amount of coolant in the system which was 150g.

I was quite happy with the AC over summer.