Outer Limits 4x4 Board

Over the last couple of weeks I have been trying to track down why the Paj is overheating (92 NH)

Have changed coolant -
Have replaced thermostat -
Have replaced radiator cap -
Have replaced top radiator hose (looked suss) -
Have checked all hoses for visible leaks -
No oil in water -
No water in oil -
No bubbles in radiator -
Fan coupling is suss but not bad enough to worry about.
Looses water - but there is no sign on moisture on the motor or under the car (anywhere - she is as dry as a bone)
Carpets are dry as far as I can see.
Car runs fine.

Car does not overheat while I am driving only when I am stuck in traffic for extended time and temp drops as soon as I get moving again.

If it was a water pump I believe I would have seen some sign of moisture by now so I am beginning to think head gasket.

I need to get to a radiator place to have a couple of tests done but thought i would ask fist if anyone has any thoughts on where else to look first ???????

Motor has only done a bit over 30,000 since rebuild.

blocked up radiator ???? try flushing it .......... clogged up fins??? been trough any mud lately??? mine had the same problem till i took the grill and fan shroud off and gave the radiator a good hosing was clogged with mud.

Noisey wrote:Fan coupling is suss but not bad enough to worry about.

I don't believe this. Sounds like a classic case of dodgy coupling. Your fan is too inefficient at idle/standstill, but cooling is OK while moving - and under more load.

My 2c,

Scott

I'm with Scott, you haveairflow whilst traveling

Ditto..........................same happened with mine.

Go the twin thermo fans!!!!!

Took the car to one of those car lover joints a week or two back and gave the radiator a thorough blasting - she's clean as a whistle.

The fan coupling still has enough grab that it has resistance when turned by hand (cold and hot) - it was replaced about two years ago and has done 40,000 tops

My concern is the water loss.

I agree it sounds like a airflow problem - so I even took the spotties off the front 3 weeks ago. I have a thermo attached as a back-up anyway so I can manage the temperature but I still have to top up the water every couple of days

Have you looked inside the cab for any signs of water (foggy windscreen), could be the heater core? Had an old Holden Gemini that did that.

3.0 v6?

Two spots for mystery cooling loss.

One of them is the Throttle Body coolant passages if yours is equipped with a heater kit for the TBody. We had them here in the US to keep the blade in there from icing in a wide open position. People clean the throttle body with carb cleaner, which they shouldn't be, it gets down into the bottom and eats up the gasket. Water leaks from there right into the intake.

The other is right past the intake gasket from the coolant passages that run through the intake manifold into the head. If you have had the heads milled this is a definite possibility.

i have a similar problem with my NH when i go 4wd and go up hills with the motor under load it heats up big time,i have renewed the viscus fan but i think it works the wrong way when its cold it rock soild when its hot its free spinning i think it should be the other way round.
Gav

Locknut wrote:i have a similar problem with my NH when i go 4wd and go up hills with the motor under load it heats up big time,i have renewed the viscus fan but i think it works the wrong way when its cold it rock soild when its hot its free spinning i think it should be the other way round.
Gav

Maybe you put it on backwards

Most likely culprit is your water pump if you are also losing water. Check for water loss at the back of the engine where you will either see staining or even rust marks. When the seal on the water pump goes the water leaks back into the valley. One way to check this is to stop the car and look for water dripping down (it may be very slow) from the firewall. If this is the case get your mechanic to check the pump.