Hi All,

I have a 2007 R51 with 2.5L diesel (Ti). When driving without camper van I sit about 93°C but will hit 100°C on a hill.

My big problem is towing a 1.3tonne (2800lbs) camper. On even the slightest incline I will reach 105°C (221 F) in fourth at 3000 rpm, and 110°C (230 F) after a few minutes of this climb now in third gear and 3500 rpm. If I do not star to decelerate to about 60kph (37mph) and now second gear I will hit 115°.

I have a brand new radiator (to try and fix this) and have had a 10" fan attached to the front trans cooler. The engine was replaced about 7mth ago due to timing chain and I was told a new water pump done at this time. I run a snorkel with sealed airbox and 33" tyres.

Any ideas? The car should tow this load without any issue but I am being passed by Kias and the likes at 100kph towing much larger vehicles.

I took it to Nissan last week and paid $250 for them to tell me they cannot reproduce the heating issue, or specifically make the gauge climb. Even though I told them it was on hills or under load towing. They said they pressure tested the cooling and no leaks.

I don't think it sounds like an air lock because I would always overheat right?

I was contemplating reversing the fluid cooling so it first goes to the air cooler (since I have the fan) and then the radiator cooling since it would be cooler now from the air and thus not hear the coolant as much. Any thoughts? Is this a bad idea?

I use Torque app via OBDII for the monitoring