{GUIDE} vz overheating problems

[dave 2007vz]

Righty o folk's , lets get rid of the myth of not having to bleed the radiator. It is imperative that you do this. The answer is staring you in the face. Cars of old and new have an intake and an outlet in the radiator, older cars the inlet hose is in the top of the radiator, In a VZ the inlet is half way up. if you do not open the bleeder on the top left hand side of the radiator, you will cause an air lock in the top 3 to 4 inches of the radiator. This air lock will remain there until the system gets that hot with steam it will cause the top cores of your radiator to blow. Iv'e had two mechanics work on this problem and they both said QUOTE,( OH YOU DON"T HAVE TO BLEED THE SYSTEM ON THE VZ>) UNQUOTE. Well after taking the day of work and fixing the problem myself. I can tell you first hand. If you don't bleed the air out of the radiator you will have continued overheating problems, as I did. One more tip, You must start the engine , turn the heater on to full and fill slowly with the correct coolant. when coolant has reached the full point at filler cap, release the bleeder on the radiator and watch the coolant level drop instantly. Keep topping up the coolant level until air stops and coolant starts coming out of bleeder. Retighten bleeder. Do not over tighten the bleeder you could crack the radiator. Keep an eye on the temp guage. If it sits at around 1/4 to 1/3 it should be good. Make sure the header tank has got the right amount and your good to go. All engines will have small galleries that wont fill with coolant straight away, Drive around for a day or so and while engine is hot release the radiator bleeder, you will hear it hiss abit leave open until coolant starts to come out, then close. Check coolant level in header tank and all will be good. I hope this helps those people who have had a bad mechanic, BUTCHER there Pride and joy.:lock:

I was told the heater box was higher then the radiator so I elevated the front to raise the radiator to a higher point then the heater box.

 

[Ol mate]

Saved the CREWMAN from cooking.

Thank You so very much for this thread it helped me out and saved me a lot of money.. Well done to every who had input. Ya all legends

 

[6shooter]

Older thread but still common problem. My sons (was mine) VZ Lumina had overheating issues. Took it to the local Holden dealer who diagnosed thermo fans not coming on and gave a quote for $730 to replace. Used the combined experience of THIS forum and got the job done for under $300 - I am a Disability Pensioner so this was critical that I fix it myself, if possible. Old thermo fans worked when hooked up to a battery - but replaced them anyway ($265 delivered). Car was boiling and fans not coming on - problem was air in the system and no coolant - just water. Fans come on at 105 deg. but water boils at 100 - so Holden dealer was right...fans not coming on - but they did work. So after replacing fans and correctly bleeding the system (thanks Mango12010)....car stopped boiling and fans come on!!! The question then needs to be asked....was the Holden dealer trying to help me or rob me?

 

[Lex]

Hi
My opinion only.
It seems to me these days all large companies are thieving bastards.

 

[RiCeY]

Older thread but still common problem. My sons (was mine) VZ Lumina had overheating issues. Took it to the local Holden dealer who diagnosed thermo fans not coming on and gave a quote for $730 to replace. Used the combined experience of THIS forum and got the job done for under $300 - I am a Disability Pensioner so this was critical that I fix it myself, if possible. Old thermo fans worked when hooked up to a battery - but replaced them anyway ($265 delivered). Car was boiling and fans not coming on - problem was air in the system and no coolant - just water. Fans come on at 105 deg. but water boils at 100 - so Holden dealer was right...fans not coming on - but they did work. So after replacing fans and correctly bleeding the system (thanks Mango12010)....car stopped boiling and fans come on!!! The question then needs to be asked....was the Holden dealer trying to help me or rob me?

Water doesn't boil at 100deg in your cooling system as it's pressurised therefore raising the boiling point. Adding coolant 50/50 will further raise it around 6deg. In a vacuum the boiling point is much lower than 100deg which is why we vac down your ac system before a recharge, it vaporises any water in the system and sucks it out.

I'd say the dealer did a poor diagnosis as the first check would be that the system is bled correctly. You can tell this by checking that the coolant whirlpools at the fill point and both hoses are hot.

You also need to find out how air got into the system, I'd replace the coolant cap as a precaution and look for any coolant stains indicating a leak.

 

[vr_owner]

Water doesn't boil at 100deg in your cooling system as it's pressurised therefore raising the boiling point. Adding coolant 50/50 will further raise it around 6deg. In a vacuum the boiling point is much lower than 100deg which is why we vac down your ac system before a recharge, it vaporises any water in the system and sucks it out.

I'd say the dealer did a poor diagnosis as the first check would be that the system is bled correctly. You can tell this by checking that the coolant whirlpools at the fill point and both hoses are hot.

You also need to find out how air got into the system, I'd replace the coolant cap as a precaution and look for any coolant stains indicating a leak.

hey Ricey, how do you diagnose a broken water pump, i cant see the coolant moving at all regardless of how much the engine revs

 

[RiCeY]

Only a few bolts to pull it off and check the blades, pretty easy DIY job

 

[robgm]

I’ve got a leak around thermostat area on my 155km VZ. Car does run but sometimes the temp gauge goes into 3/4, and then quickly drops. Anyway I’m topping up using the procedure in this thread but I noticed; when the engine is hot I have the whirlpool effect in radiator cap, but when I bleed the radiator nothing comes out. If the engine is cold I can bleed. Is this normal? If not any idea what’s wrong?

 

[scaredyet]

Does a VZ V6 engine temp stay on operating temperature or goes up and down according to traffic etc. All the cars I have driven stay a constant temp and I never see the needle move at all

 

[stick3]

everything been repaired or replaced because of leaks except the radiator in the cooling system and the and the needle stays on the lower quarter line even if i let it idle for long a long time
own it for 11 years now and done 136km
and i can remember waiting in heavy traffic and watching the temp gauge needle going up
she due for a flush, i get it done month or two