Nm overheating

[pajero122]

So my 2000 3.5 petrol pajero is getting hot.
I have put in a new thermostat. Aftermarket temp guage and new coolant

It was ok for a week. Seen sitting at the lights in town it creeps over 100 degrees and dumps into the overflow.

I have pressure tested it. Seems ok and done a carbon monoxide test in the radiator. Tested ok.

Any ideas?

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[RUGGA]

Does it suck back from the overflow tank. When was the radiator cap last changed? At $20ish for a cap, it may be worth changing anyway.

[pajero122]

Yup sucks back. Cap looks new.
It read 110 on guage and the top of the radiator felt really cold

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[Herman4x4]

How does the bottom hose feel - if cold could be a blockage somewhere.
When you turn the engine off, does the fan stop pretty much straight away - fan is cactus and needs replacing if it free spins once you turn the engine off.

Regards,
Andrew.

[pajero122]

Feels pretty cold. Fans stops instanly

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[Pickle]

Not overheating, more than likely the dodgy temp guage

https://www2.pajeroclub.com.au/forum/showthread.php?t=23477&highlight=temp+gauge+mod

Dave

[pajero122]

No. I have a aftermarket temp gauge and its gets so hot it dumps into the overflo

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[amdaniels11]

No. I have a aftermarket temp gauge and its gets so hot it dumps into the overflo

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Try and get a local mechanic with an infrared temperature sensor gun to let you borrow it, the point / take readings at each head along the length, below rocker covers, see if there is a big difference between heads' temp, and also check water hose outlet and inlet alloy hose housings temp, when engine is hot.

It is HIGHLY likely if the true temps are below 90C on the heads, then you have the dry solder joints problem on THE TINY resisitor "R10" in the back of the temp gauge ON THE circuit board/ instrument cluster. The detailed fix for this ate link : http://www.pajero.guru/how-to-fix-the-faulty-temp-gauge-on-a-pajeroshogunmontero-nm-2001-1003/ - I HAVE USED THIS FIX AND IT WORKS. You will need the biggest magnifying glass you can find and a very small pointy soldering iron to reheat/ melt and tiny bit of solder added on the left and right solder points fixing the the resistor to the board circuitry -- and DO NOT touch any other components on the board with the soldering iron!

Normally the 3.5 6G74 engine should read around 80C ~ 90C on head side-surfaces and same on radiator hose alloy hose housing, and around 75C~80C on hose engine inlet hose-housing.

If one of the heads is over 100C then you may have a blocked radiator, blocked engine cooling galleries, gunked-up radiator, worn out water pump or blown head gasket. If you can, flush cooling system with a good flushing fluid and replace with Valvoline 60% green coolant and 40% water. Check temps again.

If temps become better but are still up around 90C and not 80c~85C AT IDLE then you could replace radiator or get professionally flushed, or replace if it's original unit.

Once flushing is done - IF YOU CAN'T GET DOWN TO 85c, you could TRY ADDING add a bottle of Nulon Head Gasket repair.

If head gasket is not blown badly it will repair a slightly blown oil or water head gasket leaks until you can afford to get head gaskets repaired.