Coolant overflowing 2003 Patrol GU3 3.0L Diesel

[Hallett505]

I recently purchased this car and had a mechanical inspection report undertaken by MTA. The mechanic was concerned when the coolant appeared to be under pressure when the motor was stone cold so he undertook a C02 test and found no evidence of C02 in the coolant. I contacted the previous owner and she said that sometimes she had to add coolant if she went for a drive up into the Adelaide Hills. The motor runs fine, starts easily and the oil is still a nice reddish colour but I noticed again today after a 20min drive that the coolant was full to the top and overflowing a little. Has anyone else experienced this?

[threedogs]

Maybe you need a new OE thermosat?

[4bye4]

Maybe you need a new OE thermosat?

Worth checking - also the radiator cap as it should allow any pressure buildup to push into the overflow tank. When required the motor should pull the fluid back into the coolong system. It would be unusial for the motor to pressurise the cooland, failed head gasket or cracked head, with no indication of hydrocarbons in the water and no issues with running.

[Hallett505]

Thanks, I think I will take it for a big drive on Sunday and see how it goes. I need to be sure as the first day my son gets it off the train he has to drive it 1000km from Darwin to Nhulunbuy

[4bye4]

That should sort it out

[nipagu7]

the car is 12 years old . if the radiator cap is not holding enough pressure it might be releasing coolant but not enough to over heat unless pushed hard. radiator caps are cheap so maybe a good place to start . some people overfill the radiator and when the car warms up it spits out some coolant . when the car is cold fill the "overflow bottle" up to the maximum mark . after the next time the car is warmed up , it will suck in coolant if it needs it "when the engine cools down" . if it dosent need any more then the level will stay around the maximum mark "when the engine is cold" . ( the overflow bottle will appear over full when the engine is warm , this is normal ) . hope this helps .

[threedogs]

And as I just found out the radiator cap is on the plastic overflow bottle
the cap itself on the radiator is about $18 on Ebay, or try Mudski for one.

[Hallett505]

I think now that the caryard may have simply over filled the coolant, it was around 5cm above the Max line when I checked it this morning. We took it down to Deep Creek Conservation park today, I wanted to test the 4WD low on the track down to blowhole beach. It was around a 150K round trip at 100kph most of the time, including a long climb out from the beach in 4WD low and when I got home the coolant was still sitting at the same level, a little had overflowed but as stated, it was overfilled in the first place.

[Hallett505]

Is the cap on the radiator just a 'blank' ie no pressure device underneath?

[threedogs]

Is the cap on the radiator just a 'blank' ie no pressure device underneath?

Thats correct but saying that it still needs to seal.