Pathy coolant pressure- PLS Help us solve this mystery

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Ian_R51_Oz

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WE NEED YOUR HELP. The misses and I are travelling Oz and we are stuck in Townsville because our car isnt ready to tow our caravan.
If you can help in any way we really apprieciate it. We dont know if our car is a wreck or not. If you have a R51 Pathy with rear heater please send me a photo of the heater piping so I can check that the mechanic has hooked up correctly it just doesnt look right.

The Story
⦁ We took our Nissan Pathfinder R51 TI to the mechanics as the Pathy was abnormally creeping in temp when towing after just doing new cylinder head so we took it to the mechnics. They found and replaced faulty thermostat and a heater pipe connector 92408-EB40A was cracked something like this https://nissan.7zap.com/en/gr/pathfinder/r51m/19+1001+65535/e/278/#92414
⦁ When picking the car up the mechanic said that they ordered parts for heater piping and they never arrived(Townsville) and so they made the parts out of brass and they told us that they will never break #See below img
https://imgur.com/RXfSwAO
https://imgur.com/GwjpXuQ
we drove the car away and got 2km away the car went to 117 degrees on the obd scan tool. The car emptied a lot of its coolant. Left it with the mechanic for 5 days. Also dropped of EGR blank and they installed this and said that the engine is producing air and the head needs to be checked again.
⦁ They couldnt figure out why the air bubbles are coming into the cooling system. My observation of the issue now is that when towing a 2.5T caravan for 1 hour and 20 minutes the pressure built up in the cooling system is pushing the coolant out and creating an air lock. When I
⦁ There is still coolant in the overflow and there is still coolant visable at the radiator cap but keep driving it and it will overheat within 2km driving after towing.
⦁ Otherwise the pathy drives even better with EGR blank around town and doesnt overheat.
⦁ We didnt have this problem before we took the car in. We found that a radiator cap didnt hold pressure so we changed the cap and the system is holding pressure well.
⦁ Combustion Test already done and no combustion found in cooling system, Checked thermostat again and it does release. Pressure test done by two different mechanics and the cooling system holds pressure overnight.
⦁ Diagram of Geniune part 92408-EB40A The Pathy has rear heater you can see the kit number 92414. As you can see on this diagram there is a bleed valve and the brass parts don't have a bleed valve
https://nissan.7zap.com/en/gr/pathfinder/r51m/19+1001+65535/e/278/#92414
If anyone has a Pathfinder Right hand drive with rear heater please take a picture of the heater piping down the back righthand side for us so we can see if this is definatly connected wrong.
 
I'm going to jump in here (because this is a Navara forum, most of the people here are Navara owners that don't have rear heaters) and look at the original issue first - that of the overheating.

When towing (my van is 2550kg and we go up some serious hills to get places - Kurrajong, Thunderbolts Way just to name two) my car can get quite hot if I don't back it off, but when my viscous hub failed, it was stupid - I had to crawl up hills in first and was worried that I'd have to put it in 4LO. That fan is quite crucial and the hub drives it.

Here's how to test it. Get the engine hot - 96-97C, keep it under 105C if you can, then pull over, pop the bonnet and shut the engine down (do this QUICKLY so the thing doesn't cool off). Lift the bonnet and try turning the radiator fan. It should be VERY sticky - quite hard to turn over.

If it turns over easily, that's your culprit. There's a truck parts mob on the central coast of NSW that will sell a replacement (and mine still hasn't failed). Give them a call at Bretts Trucks, they will look after you. Changing the unit over is not hard at all, just be careful pulling the old unit (fan and all) out - you do not want to damage the radiator.

Speaking of which, did they do a flow test on the radiator? Mine blocked up its cores (during the warranty period, using the factory coolant) and needed to be replaced. That was something like 200,000km ago.

Checking the fan is cheap and might be your answer. Checking the radiator - not so easy, it's a bugger to get an endoscope into too, but maybe they already checked that?
 

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