VZ Executive Sedan 2005 3.6L Coolant Leak Right Hand Side

[AussieDave]

Hi all. I'm hoping someone can help me out. Since my last coolant change I've noticed that I've been loosing coolant after driving it around and it seems to be getting worse. At the moment I'm loosing about 500ml of coolant each day and I don't drive far in it.

I had a good look today and the leak is on the right hand passenger side underneath. There's some coolant on the base of the overflow tank and it seems to be spraying back from there on the passenger side tire and next to it only underneath. there's some spots of coolant on the ground underneath the overflow tank. The overflow tank is now over full going by the dipstick gauge. I've noticed that my temperature gauge isn't as high as what it usually is which usually sits on the quarter mark of the temperature gauge or just over when it's really hot outside. I've been checking the thermo radiator fans when I get home and keep the engine running and they seem to have stopped working.

I've tested both fans with an external 12 volt battery and they both work fine.

I've gone in to the dash menu system and the instrument temperature says 41 degrees and the coolant temperature says 72 degrees.

The low gauge temp has only started since my last coolant change and I suspect I'm having the same issue with my other VZ wagon too when I changed the coolant last. I've never had this issue before when changing coolant and strange it's happened to both of my VZ's at the same time, the coolant temp say 92 degrees. I replaced the coolant temp sensor in the wagon but the gauge temp is still low but that hasn't started leaking yet and only need to put a small amount of coolant in the wagon every couple of weeks.

I'd say it's just overheating but could anyone explain why the temp gauge is low and where the problem could be?

 

[AussieDave]

I think I may have nutted out the problem reading some threads. I may have air in the coolant system near the top of the motor where the coolant sensor is. I remember when I replaced the coolant temp sensor on the VZ wagon and when I removed it there was very little coolant that came out of the hole, it just dribbled a bit so I'd say the coolant isn't reaching the coolant temp sensor and why the dash temperature gauge never reaches the correct running temperature and why the radiator fans don't come on.

From what I've read there's a drain plug or bolt that you need to undo when changing coolant to release the air in the engine coolant system. Could someone post a photo of where that bolt is please? I'm hoping this is the fix

 

[Fu Manchu]

Bleeding these systems should be done a little different.
I made a reservoir that fits in the filler and I fill that with coolant mix.
I run the car through several thermostat cycles with some revs from time to time which gets a lot of air out. Big bubbles and the fine bubbles.
In the VZ-VE-VF you'll need someone to operate the throttle in the car. Older models could be done from the throttle body, and you'll need a heap of premixed coolant on hand to keep filling up the coolant as it's drawn in to replace the air coming out.

Holden use a special bleed kit to do this. They can be bought on eBay and Amazon.

Mighty Car Mods featured one in an old episode.

 

[AussieDave]

Thanks for your reply Fu Manchu. Late last night I read a thread about a bleed screw on the top left hand side of the radiator on the back corner which I found but is there a bleed screw on the right hand side of the VZ 3.6L motor preferably near the coolant temp sensor? I think that's where the problem is, coolant isn't getting to that part of the motor.

 

[AussieDave]

Thing is I've never had this issue before, had the sedan since 2010 and had the wagon for a couple of years now and both seem to have the same problem since my last coolant changes. Changed coolant when needed when it starts to discolour every 1-2 years. I always have extra premix on hand in the cars. I did notice that the original coolant cap on the sedan had some dried coolant powder around the inside of the cap and alloy fill tube, the cap looks ok, spring is good but the rubbers mainly the larger inside rubber is quite firm and when I cleaned it with hot water it in turned the water a light black colour so I've bought a new cap online a few days ago to replace that, I should receive that next week. I also cleaned the top of the alloy fill tube as it had some harder whitish dried coolant stuff around it. The rim of the alloy fill tube is now clean and smooth. That's all I can do for now until I can bleed the whole coolant system somehow correctly and get coolant to the coolant temp sensor.

 

[Fu Manchu]

https://www.ebay.com.au/itm/Coolant...h=item56bcbf71ba:g:hEgAAOSwip5cEdye:rk:8:pf:0