Navara overheating under load after bullbar fitting

[kiwi84]

Hi all. We had an ironman bullbar and winch fitted to our 2010 Navara d40 Thai built. It's overheating under load, say a steep hill since then. The radiator has and overflow bottle are about 6weeks old.

Could it be airflow issues eg Radiator not getting enough flow due to winch in front?

I noticed the plastic under body behind the original bumper under the radiator as well as the bottom part of the fan housing are missing? Not fitted again by ironman?

Has anyone experienced this?

Any help or advice appreciated.

Cheers

 

[Scott52]

Quote: "The radiator has and overflow bottle are about 6weeks old."

I think you're saying you've replaced the radiator and overflow bottle. So what I say below may not be relevant.

Yes I had the same problem with my 2011 Thai about 18 months ago overheating under load. After the usual checks (thermostat, water pump, thermo fan, hoses, coolant leaks, air flow restrictions) the last thing to investigate was the radiator. I tried flushing with no success so removed it and went to Natrad and had them take off the top tank. To my surprise only about a third of the radiator was flowing as about two thirds of the galleries were blocked. Considering it was the original radiator and it was ten years old I just replaced it with a new good quality non genuine Natrad branded item that cost $400.

After installing and filling with Penrite blue coolant it's been great. Cruising on the highway at 105kph it normally runs between 89C and 94C. The highest I've seen on a hot day going up hills on the highway at 105kph on cruise control under load is about 97C. As soon as it gets to the top of the hill and the CC backs off the temperature rapidly drops to the low 90's.

As far as air flow obstructions I have an ARB bullbar, two 9" LED driving lights and a 20" light bar where the winch would be if I had one.

 

[Old.Tony]

^ If the radiator is new, the first suspect is the viscous hub (fan clutch). It's really easy to test, only requires two people.

Warm the engine up to normal operating temp (you want to see coolant temps around 91C). Stop the car, pop the bonnet and have your assistant turn off the engine while you watch the fan. It should stop as the engine stops.

If it doesn't immediately stop with the engine (NO revolutions after the engine has stopped), the viscous hub is suspect. It can have more silicone oil added to it, I have done this myself but I had to suffer the indignity of entering a Toyota dealership and buying a bottle of silicone oil for $18 (several years ago now).

If it DOES stop immediately, check the fan carefully looking for cracks around the blade root.

 

[kiwi84]

Thanks so much guys for the input. Will check for the fan and fan clutch. I have had the car with two mechanics in the last three weeks. They can not find anything obvious. I was with a Nissan dealership yesterday. They have done a CO2 test on the coolant, which was negative luckily. Yes the radiator and reservoir bottle are new. The Nissan guy suggestes there are the bottom half of the fan shroud and an underbody tray missing... Or not fitted back when the bullbar was installed. They are helping direct the airflow through the radiator. I have those parts on order now. I hope that helps.... Thoughts?

 

[Old.Tony]

The car does benefit from those underbody panels.

The fan clutch is an often-overlooked item. If the fan is spinning while the engine is running "it's ok!" - but it's often not. Yes, it's spinning, but unless it's spinning fast enough, it's not going to draw enough air.

 

[Scott52]

The bottom section of the fan shroud needs to be there to make sure the fan draws it's air through the radiator not from the sides.

 

[kiwi84]

The fan stops immediately. I just checked.

The car does benefit from those underbody panels.

The fan clutch is an often-overlooked item. If the fan is spinning while the engine is running "it's ok!" - but it's often not. Yes, it's spinning, but unless it's spinning fast enough, it's not going to draw enough air.

Just checked the fan. It stops immediately when the engine stops

 

[Wayno]

^ If the radiator is new, the first suspect is the viscous hub (fan clutch). It's really easy to test, only requires two people.

Warm the engine up to normal operating temp (you want to see coolant temps around 91C). Stop the car, pop the bonnet and have your assistant turn off the engine while you watch the fan. It should stop as the engine stops.

If it doesn't immediately stop with the engine (NO revolutions after the engine has stopped), the viscous hub is suspect. It can have more silicone oil added to it, I have done this myself but I had to suffer the indignity of entering a Toyota dealership and buying a bottle of silicone oil for $18 (several years ago now).

If it DOES stop immediately, check the fan carefully looking for cracks around the blade root.

tony your onto it, replaced my radiator and it was the viscous hub was stuffed, fitted a new hub and no issue,s also thai build 2010. Did this only 2 months ago.

 

[kiwi84]

No visible signs of damage on the fan blades.... I will get those underbody parts and the fan shroud fitted in the coming days... I hope that does the trick....

But since we are towing a camper trailer there is still doubt in the back of my mind...

Is it worth exploring the option of fitting a high performance radiator for towing? (The car has a new after market radiator) Had anyone done that?

 

[kiwi84]

This is the current situation on the underside of the radiatorband exposed fan blades

 

[Erick]

Makes a big difference to both engine radiator and air con radiator to not have any air being drawn anywhere but thru the fan shroud and therefore the radiators(s).

 

[Rhino1174]

This is the current situation on the underside of the radiatorband exposed fan blades
View attachment 37312

Hi did you ever get this properly sorted out Ive just had my radiator top plastic tank split and I got to get a replacement so I’m looking to see what others have fitted to their Thai model autos and what works the best?