D40 Navara Coolant Leak

The D40 Navara is known for a few common faults. Many of which we have covered in previous articles. Primarily the review of the whole vehicle which you can find by clicking here. 
In addition to this we have covered a common cooling system issue with these cars with the internal failure of the radiator. This is something you can read up on by clicking here. 
There is one more semi common coolant leak that the D40 Navara is known for. This leak is from a part called the heater core, also referred to as the heater matrix. Basically its a mini radiator used by the vehicles climate control system to bring warm air into the cabin of the vehicle. Unfortunately this little heater holds coolant and can spring a leak.
In our experience this leak is not normally bad enough to have the vehicle run out of coolant in a short period of time. Additionally the air conditioning drainage system allows the coolant to leave the heater box via the air conditioning drain. This effectively removes any evidence of a coolant leak making diagnosing a slow leak challenging at best.
The bad news is this repair requires the complete dash to be removed from the vehicle. It’s no task for a DIY guy and will set you back around ten hours of labour.
More bad news…. this fault is very hard to confirm without removing the dash as seeing the heater core. A small camera scope can help here however we have discovered the easiest way to pick this fault is by smell.
Remove the centre console and the shifter surrounds. At the base of the dash is two plastic vents that direct air to your feet, the run down either side of the transmission tunnel. You can pull these vents off and have a good sniff. If you have a coolant leak from he heater core, this is where the coolant smell will be the strongest.
If your faced with this problem you have two options.

  1. Remove the dash and replace the heater core unit.
  2. Bypass the heater completely. This is not legal in Australia for rego purposes as you are required to have the function to dimmest you windscreen however most workshops seem to not give two hoots about rego requirements. If you go down this route you cant have warm air inside the car. So Winter will be unpleasant to say the least
    Note: the removal of the heater core or matrix does require the complete removal of the heater box. This will require you to Degas the air-conditioning system before you start and regal it upon completion.
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