Overheating GQ

[graham1]

Hi guys I just popped out early this very chilly morning and about 5 mins into the drive I noticed the temp gauge rising quite fast, way past half way. I got up to some speed and coasted and the gauge came down again. Anyway, I turned around and came home, doing the same thing the whole way. The gauge on occasion got over three quarters.
I checked when I got home and I see the fluid has leaked from the rad cap.

Now, is the reason for the overheat because of the rad cap? Or is the leaking rad cap due to the overheating?
Not really sure where to even start here.

It was last driven two weeks ago to pilansberg and back with no issues at all, but now has this issue all of a sudden on a very chilly morning?

[Tinus lotz]

Is your water pump belt there and vas?

[Tinus lotz]

Check the piece of pipe under your lid of expansion bottle some times it falls of and then cant suck water back .
Also look under the inlet if there is any leaks on all those pipes there
Viscus or thermostat? If your water level as low replace the cap and check for leaks

[graham1]

Thanks for the reply.

I've checked all those, everything seems fine there, water pump and belts all good and no sign of leakage anywhere except at the rad cap.
I took the cap off the expansion tank and blew into the pipe (probably not the wisest idea, but anyway, I did it before thinking). I could hear the air escaping from the rad cap, this was when the engine was cold again.
I then started her up from cold a and let her idle while I stared at the rad cap, two drops formed just under the rad cap, where the other pipe joins that runs to the thermo, but each time they came while I took my eye off for a second! I'm sure it's the cap and not the pipe joint though.
Anyway, I had to switch off as the temp gauge started to get to three quarters again.

I've put the cover back over the old girl and left her for today, I need to walk away before I set her on fire out of frustration. :)

[petrol]

How long does the vehicle idle from cold before hot?
Does the radiator get hot or can you still touch it while the temp guage shows very hot?
Open oil filler cap and look inside the cap, what does it look like, is the oil foamy mayonaise like?

[Tinus lotz]

Sounds like viscus coupling does it feel ok?

[petrol]

Dit is moontlik dat dit viscus kan wees Tinus maar viscus speel nie n groot rol wanneer engine net idle nie

[bogeyman]

I would replace the thermostat , fan and viscous coupling , radiator cap and the gauge sender unit with genuine Nissan replacement parts immediately to be sure. Also make sure the coolant circulates and is not hampered by an airlock.
If the problem then persists the radiator core must be cleaned and the water pump impellers must be checked for corrosion/cavitation.

Obviously , any changes like spots/bulbar/winch or grass seed net recently done will also affect cooling.

[Peter Connan]

When the temperature gets too high, the radiator cap opens and you will see a leak there when this happens. This is correct and does not indicate a malfunction of the radiator cap.

This sounds very much like an airlock-related problem to me, but I would also definately replace the thermostat.

[Wilkie]

easy test...take the radiator cap off and start the engine with heater set to hot...fill up radiator and start the engine and rev at 1500rpm
the water in the radiator should rise (not circulate) slowly until it gets hot and bubbles over,then feel both upper and lower radiator hoses and they should be equal hot..
if the water is not circulating then you have a thermostat or waterpump problem but starting with thermostat first...take it out and throw it into boiling water ..it should open if its working correctly

if you still sukkeling PM me