Outer Limits 4x4 Board

I have just returned from an eight day trek from Mansfield right up to Tom Groggin via Wonnangatta and Dargo etc. We had an awesome time however on our third day, I was on the link road from Sheepyard Flat heading toward King Billy Track when my GQ started to run very hot after a bit of a hill climb. My initial thoughts were that I had busted a fan belt or the water pump had packed in and it would be a limp back to Mansfield to get the thing fixed. I decided to take a look at the coolant level which was a little low so I topped that up and hit the road again. When ever I was heading down hill on decompression the temp gauge would return to a normal level as this was the case, I assumed the water pump must be doing its job and we continued on our way. Every hill I got to, the temp guage would sky rocket up again. Any suggestions as to whats causing it?

radiator blockage, mine used to do it under load and when you back off would cool down so get your radiator serviced they will pull off the header tank and clean it out. Sure it will work

Has been discussed before, but check: Radiator fins clean--will require removing shroud, thermostat sticking,clutch fan not operating properly--should be slightly stiff to turn with a cold engine, water pump blades worn causing cavitation. Check that the seals that seal the radiator to the body are ok.

When you say its running hot, how far up the gauge scale is it actually going? 1/2 to 3/4 is not overheating when engine working hard.

Nick

Its definatly running hot, it has never gone more than about 1/2 way on similar terrain when doing a bit of work. It was going right up to near the top on this trip. There is a line just below the H and in the manual nissan say that up to that line is the safe working limit. It was pushing pretty close to that line.

Sounds to me like your thermostat is not cracking far enough anymore, sooner or later they will do this and it will only get worse!
Buy a genuine one and bring both almost to the boil on the stove to see how far it should be cracking and when it should start cracking!

Over 20 years I have replaced around 8 stat's for this reason alone, today with cooling probs it's the first place I look esp if everything else seems to check out. Last dodgee stat was a brand new genuine to replace the buggered genuine in the TD42 so it's worth cracking them on the stove before fitting.

cheers fnq

i just had this problem sorted tryed everything new thermostat ,chemical flush etc was getting up to 3/4 which just going up a hill shouldn't do as does not leave much room for error when you are in the soft stuff.
Got radiator pulled apart and they used a brush to clean the cores works 100% better now . NEver goes over 1/2 towing my trailer up long hills usually runs less than 1/4 temp

BTW last time i cooked my motor it was the thermostat. As fnqcairns said buy a new one regardlee i change mine every 12months as insurance

RE-fnqcairns idea, had same problem,did same thing.
It worked.
Pat on back for fnqcairns

Ian