Ideas anyone...4.5 Mystery overheating - NOT the usual suspects

[zerolux]

G'day

Got me absolutely stuffed...

Have replaced Radiator, Thermostat, Hoses, Water Temp Sensor, Coolant Sensor, Clutch fan is Ok, cooling system flushed, new waterpump, not using water, and its been 6 weeks and the patrol overheats again...

Temp rises quick, car feels sluggy, pulled over at just over 3/4 on the dial, (didnt want to cook it) let it cool down, add 4 litres to replace what boiled out the overflow and off we go again, no issues.... NOT overheating

Dont know what or where the problem went, but thats the 2nd time and the mechanic has pressure tested, gas tested, checked mixtures, timing, leak down test and cant repeat the issue.. He says try nissan to see if there's a known issue, as he's buggered, and i went to him cause it had me stuffed

So anyone, please, I need help, this is the family car and last time the missus and kids got caught on the highway (other half says it lost power, started to ping and the engine stopped, but all the steam says it was cooked that was the 1st time and i replaced everything), this time I was there, but I cant trust it to let them leave town, so to speak.

any suggestions greatly appreciated

Jarrod

[threedogs]

Pull the guts out of the thermostat, still restricts it but more free flowing, use your old one for this.

CRACKED HEAD???????

If you run a hose through motor with thermostat out will it flow, maybe, just maybe an internal blockage????

[zerolux]

yeh, my thought was cracked head, but no smoke, no steam, no exhaust gas in water, and no water in oil...might try the thermostat trick, but its been 6 weeks since the last overheat, so its pretty intermittent

[threedogs]

Don't you hate that, I feel for you buddy, maybe a faulty sensor somewhere??, bad earth??, cant have enough earth straps, loose connection, running out of ideas too. just throwing them out there, still thinking sensor though,

[nissannewby]

Try and get a hold of a mechanical gauge and put it temporarily so you can see what the temp is actually doing when the gauge says its getting hot. It could be a blockage in the auto cooler or the engine oil cooler on the side of the block possibly.

[threedogs]

Yo Jarrod fill out your signature so we know what you drive and what you've done to it, sometimes all info helps Edit in settings

[nissannewby]

Does it not have the recovery style cooling system on it?

[threedogs]

X2 with Nissanewby again get a external pyro reading of the radiator and see if guage says the same thing

[threedogs]

Is it dual fuel???????

[threedogs]

Yo Nissannewby what about an air lock in the cooling system, on my old truck a 350 Chev Troopy. I always inverted a coke bottle in filler on radiator to lift water level or top up an a steep slope with front of car up