LN65 Dual Cab Hilux with VN Series 2 V6 Heating issues

[zuker1500]

Hi All, I know there has been a bit of discussion on v6 commo motors in hilux's heating up. Well i have searched and searched and i cant come up with an answer so here we go.

So its a standard v6 vn series 2 v6 in an ln65 hilux running 33's

Problem is its getting hot on the highway.

A little history first.

We ran the stock diesel radiator and a davies craig thermo fan which seemed to be ok, got a little hot in soft sand but not too bad. I wanted the air con working and was told that the radiator wasnt cooling enough for the air con condensor to work correctly (little bit suspect but feasible) so the radiator shop proceeded to retro fit a commodore radiator with the commodore thermo fan.

All sounds good, air con working ok around town, temps are all good around town and slow wheeling no worries at all, Air con super cold and all good, Until you go out on the highway.

Temp goes up to over half and thermo stays on whilst on the highway and air con isnt working that well. Even worse towing the camper trailer.

Came back from cruiser park yesterday and it was about 30 deg outside, thermo just ran the whole way down the bruce highway and temp was about 3/4. Running on the highway at night it seems to be better and thermo only comes on every now and then.

So how do i fix it? Farks me!!!!! have taken the spotlights off the bullbar to allow more air into the grill, helped a little bit. Have fitted a new thermostat. No change. Checked for all other kinds of normal heat ralated issues, ie: water pump, all new hoses. Still no joy.

So whats causing it? Obvious to me its air flow related. It there a vacuum being created that doesnt allow hot air to escape the engine bay? Have had it back to the air con/radiator guys and they cant figure it out. Have bled out the system and there doesnt seem to be any air locks.
Maybe the hilux radiator sits a little lower than the commodore one and gets a little more air flow or disturbs the air flow enough to stop the vacuum under the car and allows the hot air out.

These are all theories and i just an at my wits end, and also spending way too much money trying to sort this out.

So what do i do? Just put the hilux rad back in and see what happens? or do i try and make the commodore one work?

Any ideas or theories would be appreciated!

[samdumbert]

Is the electric fan spinning the right way?
Is the fan on all the time?
Was the commo rad new or used?

[zuker1500]

Thanks for the reply!

I can confirm the electric fan is spinning the right way. It pulls your hand into the grill it has so much air flow. As i said at low speed, around town and crawling it all works really well. its only an issue when on the highway.

The fan only comes on when the computer tells it to or when the air con comes on at low speed.

The commodore radiator was a brand new Adrad radiator

[Rilux]

Seems funny it's overheating on the highway when you should have good airflow

Whats the water pump like? Maybe pull it off and have a bit of a gander?

As you said the only other thing it could be is that the hot air is being trapped, maybe it needs a shroud above the radiator or something??

[howsie]

When doing freeway speeds the airflow alone should be sufficient to cool the engine with no assistance from the fans. Is check radiator cap, thermostat and look for old cracked hoses. Maybe putting in a lower opening temp thermostat would help

[zuker1500]

Thanks for the replies all.

Yeah we have tried a few things like:

All new hoses
Lower Temp Termostat
No Thermostat
New Radiator Cap
Have checked all water flow, and i guess that if the water pump was failing it would be an issue at crawling speeds which it doesnt seem to be.

At all stems down to air flow and not getting the hot air out. My thoughts are the standard hilux radiator sat lower and provided like a disturbance to air flow under the vehicle going into the engine bay and then creating like a vortex to pull the hot air out. With the commodore radiator not being as deep down the air flow under the car is acting like an air wall and not allowing the hot air to escape. A bit like the old style air walls over open doors that done let the air con out.

Before i moved the spotlights on to the top rail of the bull bar it would just stay at 3/4 on the gauge and even with the thermo running the temp wouldnt come down. Now that the spotlights are on the top of the bar the temp comes down a little but still not real flash.

But the wierdest thing is that at low speed, crawling and in heavy traffic all is good, its just on the highway and then hence thinking that the hot air is not being allowed to escape.

I might look at lifting up the windscreen end of the bonnet about 25mm so the air may flow through.

Its a bit of a pain but i am sure there will be an answer somewhere.

[UhhOhh]

Couple things might help ya mate:

- Engine must have thermostat fitted, removing it will cause overheating especially on freeway.

- Thermo fan is useless on any speed over about 30km/hr, its only use in this instance is to tell you the approximate coolant temperature as the factory gauges are useless.

Best advice get your thermostat back and fit a proper temperature gauge to really see what's going on. You might find the engine temp fluctuates to around 95 degrees which isn't terrible but you really can't tell with the factory gauge.

[zuker1500]

Thanks dude, yeah we put the thermostat back in straight away as it didnt do anything.

Proper gauge is in just fitting the sender to the thermostat housing to see whats going on.

I am pretty sure its not getting enough air flow and its just staying hot under the bonnet as the air con isnt working very well on highway speeds but is fantastic around town.

Very unusual problem. I guess the only thing to do really is go back to the Hilux rad and see what happens??

[samdumbert]

I would try disconnecting the fan and drive on the freeway and see what happens first, before swapping everything back.

[zuker1500]

I would try disconnecting the fan and drive on the freeway and see what happens first, before swapping everything back.

I am guessing it would just overheat??? Will try it this afternoon and see what happens.

[Frankenyota]

Check what temps you get on a proper gauge, as V6 commodore motors run hot.
The fan on mine cuts in at 105c.
Do you have a fan shroud?

Matt

[zuker1500]

Ok so i did some experimenting yesterday afternoon and here is what happened

Installed a cut off switch to the thermo fan. Left the led on from the output of the computer so i can see when the computer wants the thermo on.

Went for a drive up kingsford smith drive with reasonable traffic. Temps were ok, only really had to turn the fan on once as i was at a set of lights. Basically as soon as you start moving temps on the gauge come back to normal and computer doesnt want the thermo fan to come on.

Then went for a cruise up the gateway. All was good in traffic at about 70-80km/hr. Computer didnt want the thermo to come on at all, until i went up to 90-100km/hr. After running at 100km/hr for about 5 minutes the temp started to go up and the computer wanted the thermo to come on. I left it for a while to see what happened and it got pretty hot. I then backed off to 80km/hr and after about 4-5 minutes at 80km/hr the temp started to drop.

So what does this all mean???? Well i think airflow is the key, it gets to a point where no matter how much air you get in there is no where for the hot air to escape. It seems that the more air that comes in it creates like a vacuum and doesnt allow the hot air to escape.

So what to i do??? Well i think i might lift the windscreen end of the bonnet and see if that helps to let some of the hot air out. I might put in some kind of scoop under the radiator to try and channel more air in and also to try and disturb the air flow thats going under the car.

Ahh the joys of having a modified car.

I guess if all this doesnt work i will just go back to the Hilux rad.

[zuker1500]

So having a bit more of a look. It seems that the commodore radiator is quite a lot smaller than the hilux one. It should still be ok but just something that i noticed.

At standstill we were looking at where the air goes after it passes from the radiator and well we might bo onto something. There is no where for the air to go. Its like the hot air is just hanging around.

Air comes in through the condensor, then to the radiator and then through the thermo fan, after the thermo fan there seems to be no where for the air to go.

I have put some pics of the engine bay into photobucket. Here is the link http://s556.photobucket.com/albums/ss1/ ... 0Radiator/

Just shows the gap. When the thermo kicks in it just doesnt seem to move air past the block at all, just all hangs around the thermo area.

Can anyone post up some pics of their engine bay, mainly the radiator area of their V6 conversion??

The commodore thermo fan is designed to suit the commodore where there is like 300mm from the fan to the engine block and therefore plenty of room for the hot air to escape.

Hilux radiator here i come, i think, unless there are some others that have had success with the commodore radiator.

[howsie]

It's not as unusual as you might think my old mans xf falcon ute with thermofan does this too. exactly what your describing.

If youve checked all other aspects of cooling system and theyre good then It's simple.

1. Must have fan shroud
2. Is air escaping engine bay.
3. Is there sufficient air flow

Dads xf was fine till he put the five poster Bullbar and spotties on. Maybe look at adding a pusher fan to the front of the radiator to assist in inflow. Maybe some custom air ducts to rerout air flow to radiator and some near firewall to assist in letting heat out. I have heard of all these being tried with varying levels of success.

[Frankenyota]

I have no rubber strips in the front guards between the body and chassis.
Maybe remove them and see if the heat can escape?

[UhhOhh]

Is that a V6 radiator? From memory the V8's were the same mount but half an inch thicker in the core. Also the thermo running at high speed may cause over heating as it traps the air being rammed through the radiator that should over wise flow through.

[zuker1500]

It is the V6 one i believe. Will check it out tomorrow. It does seem rather narrow.

The thermo only comes on after running up the highway and the engine temp creeping up to the point where it needs to come on.

When i tested it without the thermo on it got real hot as per the earlier post.

Fortunately for me the radiator company i have been dealing with have now screwed me over even further and have lost the sender unit for the temp gauge that i bought, so now have to buy another temp gauge cause it was a cheap one from super cheap and you cant just buy the sender unit. Imagine going to a radiator/ac shop to get the air con fixed and then have your car overheat on the highway. Damn shame that!

Where have you guys with the V6 conversion fitted the sender for the aftermarket gauge???

[stilivn]

I thought you fit the guage just before it re-enters the radiator. Time to start cutting a big hole in the bonnet

[Frankenyota]

In the manifold under the thermostat area. Mine replaced the standard one.

Matt

[howsie]

Depends on what your measuring under a head bolt is most common as both manifolds in and out give bad readings from what I've been told. exhaust manifold because of hot exhaust gas and manifold because of lower temps. Engine temp will always affect.the head first.

For water temp as mentioned in water return feed for radiator as water temp exiting the block is what were trying to measure.

[zuker1500]

Thanks for the help guys.

After speaking to another radiator shop recommended by Damo the comment was, "Why did you replace a 3 core radiator with a 2 core radiator?"

Basically, the standard V6 commodore radiator is a 2 core radiator and the standard hilux radiator is a 3 core radiator. the V8 radiator would of been a better choice. Standard hilux radiator is 450w x 523h x 45thick, the standard commodore one is 546w x 418h x 25thick. Goes to show that as its also a little less taller than the hilux one it doesnt disturb the air flow under the car enough to create a vacuum and draw the hot air out. the V8 radiator is a 3 core and is 545w x 428h x 49thick.

So after a bit of a discussion the decision has been made to go back to square one and fit the hilux radiator back in, but with a thermo fan, the SPAL brand (or ebay copy) that puts out about 2500cfm. That will keep it cool whilst wheeling and in traffic and also the air con will work well at low speed. Hi is also going to modify the inlet and outlet points to it will fit the commodore motor better in terms of where the hoses lay, and also will fit in a sender unit for the gauge right at the inlet.

Well yep a bit of a win win, although its going to cost me more cash (p1sses me off a fair bit) it should be where i used to have it but with air con working

Does anyone have any pics of how the original hilux radiator mounts back in? I will have to go to the wreckers and try and find the radiator support strips or just make something up out of angle.

Hopefully we might be able to achieve it this week.

[Frankenyota]

The temp sensor position is in the manifold before the thermostat, factory position and would be the best / easiest spot to put your sensor.
I have dual Spal fans on mine, work fine.
What condensor a/c set up do you run?
I was looking at doing a/c in mine but don't have all the parts and the evaporator i have has a leak.
Looked at getting a new one but they no longer have a listing for that model

Matt

[zuker1500]

Hey matt, what size thermo fans are they? I was looking at a single 16" any chance you might be able to take a photo of your radiator/thermo setup and post it up?

With the A/C everything is standard hilux except for the compressor which is the commodore one.

Gets super cold, great for those hot days wheelin!

[Frankenyota]

My fans are 11" ones, but a 16" single fan should be fine.
I think i went the dual fan route as it had more cfm's, but this was a few years ago now.

Matt

[howsie]

FYI spal do a 16 inch thermo with a 3000cfm output twin 12's are just over 4000cfm