VZ Overheating!

[me&myVZ]

For the last week my VZ has been overheating when the air-conditioning is turned off! Today I took it for a drive and the flashing warning came up saying Engine HOT, I pulled over and turned it off, for about 5mins the fans continued to run and eventually turned off. I have been topping it up every afternoon with coolant and The Radiator Cap has been replaced. Any idea? The car has done 120,000kms and has always had its interval services. Also what cost am I looking at to fix it?

[rabs]

Vz commodores are bad for overheating when the system has air in it.
Check the heater tap to make sure it is not leaking out of the centre which is common for them. Also check that the water pump is not leaking down the front of the motor, which is also common. If they all check out fine you will have to bleed the system. The correct way is to open the bleed screw on the drivers side of the radiator, fill the coolant up untill the air has been blead out, close the bleed screw. leave the cap off and start the engine up, turn the heater on to full hot with the air con off, bring the revs up to 2000 rpm and hold there untill the fans turn on, ( this will take a while as the motor has to reach 108c so that the fans will turn on) once fans are on let the car idle while filling the coolant up as it would have spewed a lot out while reving it, once fans turn out, turn engine off and then bleed the system again with the bleed screw. See how you go with that, but make sure none of those things are leaking, because if there is a leak it will get air back in the system and you will have to bleed it all over again

[jr689]

I have been topping it up every afternoon with coolant

Hey mate so it's been losing coolant and not just overheating?

[azazeldeath]

This may be fairly obvious but, have you checked your oil levels and quality? Remember if the oil isnt doing its job it will heat up from the excess friction. Otherwise rabs has the other solutions I would have mentioned.

[me&myVZ]

Thanks for the replies! Yeah it appears to be losing coolant as the levels seem to be dropping quite fast and overheating as soon as the air-conditioning is switched off. The Oil is quite new and has no signs of coolant in it so I have ruled that out. Thanks Rabs I will give that ago tomorrow! Could it be a Water pump or a thermostat? I heard the thermostat is a shit install and could cost me a bit!

[db_notso]

okay...
fill her up at the cap
let car idle until warm and some pressure in rubber pipes (feel them if feel stiff okay if soft bad)
when some pressure in it (or if no pressure in it after 5mins at idle);
look under you cars engine and see if any drips of coolant from either sump or gearbox (not the a/c drip of water on the left hand side)
if its dripping follow it upwards until you find a leak

the thermostat is at the back imbetweeen the firewall and the engine and its the biggest pain in the ass job ;(
but if its from the front (normally water pump shaft leaks onto case or heater pipes or outlet o-rings) then is easy repauir and much much cheaper

[calay]

I've had the radiator cap replaced (under warranty)
the water pump replaced (under warranty)
and now the radiator itself replaced (under warranty)

3 different items replaced several months apart...

And now my cooling system is working perfectly !!!

So there may be more than one thing not quite right - it would pay to take it to a radiator specialist or a holden joint to pressure test it and have a close look, you don't want to have to buy a new engine cos you overheated it...

[me&myVZ]

I was driving to the Mechanics today when it overheated and started making a really loud Noise that sounded alot like a flat tire does under the engine on the passenger side I instantly pulled over. After having it towed the rest of the way I ended up having it Pressure Tested and it returned no leaks! The Mechanics at "Holden" were dumbfounded.... flushed the radiator and re-filled it!! And then told me that I would need to have it serviced by a Specialist Mechanic from Holden that is only available Monday Tuesday, Thursday and Friday!! NOT HAPPY!! I didn't pay and told them that I will only be paying for Parts when I return and not Labour!

The Receipt I was given says:
Engine was pressure tested and showed no leaks cracks or air.
Fans, Thermostat, and water pump were tested for effectiveness & normal wear and tear and were all in good condition and functioning properly. Water pump also showed no signs of a leak.
Engine oil is clean and showed no signs of coolant, and will not need to be replaced untill your next scheduled service is due.
All engine levels are correct, and not contaminated with coolant.

Labour and equipment: $250
Parts / Engine Oil, Coolant and other: $50
Total:$300
Paid $0
Owing: $0

[alex2_s]

Is the thermo fan coming on when necessary. Also possibly a stuck shut thermostat?

[me&myVZ]

Yeah the fan was tested and apparently is working properly and is turning on after it gets to a certain temperature, And the Thermostat was working perfectly. The bloke that serviced it yesterday said that there is defiantly a leak somewhere but they just don't know where as everything they checked was fine. So I haven't the slightest idea what is wrong with it! Got it booked into the first available spot at Holden Tomorrow to get it seen by there so called specialist.

[delidean]

I'd take it to a radiator specialist. My VZ was leaking coolant for months, needed topping up every few days and couldn't see where it was going. Found out it was leaking from where the radiator clips to support. Natrad dude said so many have cracked in this spot. It's hard to see cause fan blows coolant around and it's only a very small leak. Cost me $400 new side tank on radiator. hope it helps!!!

[me&myVZ]

Had it back in today and the Specialist himself spent a good hour looking for the leak, he ended up tracing it back to exactly what delidean has suggested that my radiator tank has a tiny crack in it! I don't know how they didn't find the leak the other day, but that is what it was. Thanks for everyones help!!