{GUIDE} vz overheating problems

[Mango12010]

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:

 

[KrisHolden]

Thanks heaps mate. Im still waiting for a hot enough day to test my system out.
I reckon they havnt bled my system correctly (and for the 2nd time). I doubt they even used the heater too.

 

[Torquative]

I'll agree with that

Mine had a classic case of the bung Thermostat issue - ie jumped to hot and wouldn't cool down.

After talking myself into buying the $100+ Thermostat and put in the many hours throughout the night before a track day, I decided to start with the basics by bleeding the system.

Sure enough a big shhhhh was released from the tank when I opened the bleed screw, and it drank a bit of coolant.

I think when I jacked the rear end up to climb under to the diff I must have created an air lock at the front. either way, with them being so damn easy to bleed its definitely worth it!

 

[Mango12010]

Butchers who call themselves mechanics,

:rofl2::rofl2::rofl2::rofl2:

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. I've 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. Re tighten 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 a bit 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:

 

[MARIO2]

Thanks for the info ,very handy

 

[RiCeY]

Just to add when its bled up correctly the coolant will whirlpool at the fill point. If it isnt, either the thermostat hasnt opened or theres still air in the system.

 

[morphix]

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'm currently having my car randomly overheating, i can go from a cold start, drive the car for 10-15 minutes up the road and it can go from 1/4 all the way upto to H, then in the same small time frame it will drop back down to half.. then continue to go back up again and then drop, once it gets too close to the H i stop the car and leave it to cool down.

I am just wondering what u mean by 'full point of filler cap' ? There is only the coolant reservoir at the front right (if standing in front of the car staring at the engine) which has the level where mine continually sits in the between the 2 arrows.

Also, where and what is the 'header tank' ?

Sorry to sound stupid, but my understanding of cars is not a great deal, which i'm slowly trying to educate myself and gain more knowledge.

 

[RiCeY]

Sounds like an air lock in the cooling system.

Filler cap is generally a black cap on the front end of engine, passenger side, next to power steering cap.

He meant the tank with the yellow cap, the over flow tank. Coolant bleeds into it when hot and is drawn back into the system when cold.

 

[morphix]

Oh ok, so that would be the little black cap underneath the shroud on the radiator, little thin pipe, around 3-4cm thick.

Again i am confused, do i turn the car on and let it sit for a little bit, then undo the bleed screw, pour coolant into the coolant reservoir until coolant comes out of the bleeder and then tighten it back up?

Or do i pour the coolant into the coolant/radiator cap at the front of the engine? Or should the car be off?

I've never had to do this before, just an FYI, my radiator was replaced around a month ago as the trans cooler was blocked and have only had this overheating since then.

The mechanic who did it was a dick and spent more time on his mobile when under the car then doing the work (mobile mechanic).

 

[RiCeY]

No, its plain as day on the engine next to the power steering cap, how can you not see it?