{GUIDE} vz overheating problems
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.
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.
go in Luxury
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!
Butchers who call themselves mechanics,
Originally Posted by 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. 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.
Thanks for the info ,very handy :-)
F O R U M W A R R I O R
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.
Silver Certified.
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.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.
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.
F O R U M W A R R I O R
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.
Silver Certified.
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).
F O R U M W A R R I O R
No, its plain as day on the engine next to the power steering cap, how can you not see it?
Silver Certified.
Ah yeh i understand which one you mean.
F O R U M W A R R I O R
ok remove that cap, good chance its knackered so have a new one handy.
Run engine, have heater set to full hot but fan off.
Top up with coolant till full then open bleed screw on radiator and leave open till coolant flows from it. Then close it up and keep topping up till bubbles stop coming out and the coolant forms a whirlpool. It may overflow as it heats up this is normal. Clamp off the hose that goes to the overflow or that will fill right up and overflow. Every now and then reopen the bleed screw and make sure theres no air in there.
Silver Certified.
I called past Holden yesterday and got a brand new cap as my current one was starting to break apart (rubber) and also read this to be a good starting point of overheating issues.
So i top the coolant up via the point on the engine, how do i determine when its full? The coolant will form a whirlpool at this point on the engine?
I assume you mean the coolant reservoir? What would be best to clamp this hose off?
Sorry to keep asking questions, i just don't want to do it wrong and mess something up.
F O R U M W A R R I O R
Yes fill at the metal spout where the black coolant cap goes on the engine, its full when you cant fit any more coolant in haha. Yes it will form a small whirlpool in the metal spout.
Fold it and chuck a clothes peg on there if you dont have anything else.
Better to ask than do it wrong.
Silver Certified.
Ok thanks.
Can you also confirm this is suitable coolant Nulon Long Life Coolant - Supercheap Auto Australia as i currently don't have any and haven't needed to top up the coolant since i got the car (it hasn't budged).
Some web searches are stating Red coolant? My car has had Green coolant in it the whole time (mechanic put it in) and even after the radiator was replaced.
I called SCA to confirm if that coolant is suitable to which she states "Yes, i guarantee it" but i want to be certain.
F O R U M W A R R I O R
Should have the red stuff, genuine holden stuff is what I use in my own car.
Silver Certified.
Well i gave this a go on Saturday as it was bloody hot and i really needed to use the Air Con (plus a simple 2-5km drive the car was overheating).
Did as directed, but there was no hiss noise at all, but i kept filling the coolant up till full, making sure that the reservoir hose was clamped to not overfill.
Let the car run for a good 10-15 minutes before i drove it.
Took it for a 3 hour solid drive and it didn't overheat at all, it sat roughly 1-2mm over the 1/4 line, which was great.
Checked coolant level later on from reservoir and it was still all fine, just like before i did it.
thanx Mango12010 .
mine heated up like Torquative's did , but i found this thread b4 getting a new thermostat
mine drank a litre after opening that screw .
most favourite JC post - I'll be head'n to the wrecker tomorrow for a new one.
I'm just glad my overheating issues have stopped, as it is my transmission is pretty much stuffed but i need to drive to work so i still use it till it dies completely, i don't need any unexpected expenses (eg. water pump).
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