VZ Alloytec - coolant boiling in the reservoir

[le-jarryd]

First off, Hi I'm new here. Driven here through desperation, but here all the same.

Second, yes I have searched for threads on this topic and found a few, I feel that my issue is sufficiently different so here I am with a new thread.

So I've just picked my car up after a service (200k) and after 20-30 minutes of city driving the coolant temperature is sitting at around 106-108 degrees when idling and 102 when driving. When I turned the car off I could hear the coolant bubbling away in the reservoir. I need to know what I should be looking at to fix this, because the water pump is brand new, the head gasket is fine (I specifically asked the mechanic to check it out), I have a new radiator cap, the heater tap was replaced yesterday, the reservoir bottle was changed last year and its not losing any coolant. I re-bled the system twice after pick-up to make sure it was done properly.

The car isn't overheating per se (sitting at just over the 1/4 mark on the temperature gauge in city traffic) but the system isn't pressurized somewhere because the coolant shouldn't be boiling at 102-105 degrees. Could faulty fans be causing this? Could the reservoir cap (the yellow one with the dipstick) need replacing? Thermostat or inlet manifold gasket (I asked my mechanic to check both of these and he said they were fine)?

I might have to give up and take the car to Holden, and then give them all of my money. I guess if anyone knows a really good mechanic who knows their way around a Holden please shout out.

Thanks!

 

[Trayner]

Id say there is air trapped somewhere

 

[le-jarryd]

Id say there is air trapped somewhere

Thanks mate, is it as simple as re-bleeding again and again, or is there another way to release air that I'm missing?

 

[Trayner]

Thanks mate, is it as simple as re-bleeding again and again, or is there another way to release air that I'm missing?

Have you tryed doing it with the heater on full blast ?

 

[AdventraAddict]

OK been here myself
Thermo fans low speed comes on at 108 and high speed at 114 degrees (hotter than the old ecotecs)
When you are rolling with free air flow they run about 93-95 but in slow moving traffic 102-106 is normal.. (couple of mm above 1/4)
The radiator has a bleed screw on the driver side at top. Other than that bleeding is a doddle, if it is all bled up and running normal temp range. I suspect you have the same issue I did. Faulty new radiator cap.. Is it the plastic type or the spring type? early VZ were a spring later the plastic O ring type. If its O ring type suck through the bottom of it you should draw air really easily through the return valve.. If you dont that's your issue.. As I said had same symptoms and chased my tail all over. I was watching my temp through OBD2 and all was fine then Id stop and it would boil and vomit coolant a little.. What was actually going on was system is negative pressure because it breaths out but cant draw back properly on cool down.. Low pressure=lower boil point and overflow was overfilled as I kept topping up just a little everyday whilst working it out...
Low speed fan relay is the one closest to the guard when you look at the diagram in the relay box if in doubt swap with high beam relay. Also to test the system integrity the coolant should run in low to min 90s with aircon on...
Put your dash into diagnostic mode when you start up to get digital coolant temp...
Hope that helps

 

[AdventraAddict]

How you go?

 

[Benboy]

It would be extremely unlikely that the coolant would (could) be boiling in the overflow bottle. As suggested, most likely trapped air. You can spend time trying to bleed the system manually. Suggest you leave the system alone for a few days and the air should find it's way out - as it has been already doing. If you are really worried about it, take the vehicle back to where you had it serviced and let them deal wit it. It shouldn't still have air in it - if they did their job satisfactorily.

 

[Nathan923]

Hi guys, recently bought a VZ sv6 from car city. The dealer I got it off obviously dodgy and didn't want to help at all. I literally had it 1 day had leave it to mechanic, was leaking coolant and overheating. He said nothing to do with him. Also hada replace the diff and put new discs because brakes were dreadful.

Everything was then fine then last week, turned car off and coolant started bubbling. And the heat coming off the car is serious? The fans don't come on when you turn car off only when I turn aircon on? Don't no much about engines and want to get this sorted cheap as possible before something major happens! Any help be greatly appreciated, thanks

 

[Benboy]

Hi guys, recently bought a VZ sv6 from car city. The dealer I got it off obviously dodgy and didn't want to help at all. I literally had it 1 day had leave it to mechanic, was leaking coolant and overheating. He said nothing to do with him. Also hada replace the diff and put new discs because brakes were dreadful.

Everything was then fine then last week, turned car off and coolant started bubbling. And the heat coming off the car is serious? The fans don't come on when you turn car off only when I turn aircon on? Don't no much about engines and want to get this sorted cheap as possible before something major happens! Any help be greatly appreciated, thanks

Sorry to hear about your problems. If you bought the vehicle from a Dealer, then you would have some redress under Consumer Law. In some States it is illegal for a Dealer to sell any vehicle that is not 100% roadworthy. Sounds like your brakes were not up to standard and therefore should be repaired by them. Suggest you contact Consumer Law in your State and seek advice. Such shonky sellers should not be allowed to get away with such behaviour. Good luck.

 

[ALCMCQ]

There is no statutory warranty (in Victoria at least) for cars sold through a dealer if it's older than 10 yrs.....however if they sold it with a RWC you have recourse to whoever has certified it as RW (as it seems it ain't with shot discs...) I'd be waving that around in front of the dealers face to see what if anything they will do to help you....if no joy then off to the consumer comission with all the facts...dodgy dealers need to be driven out of the business...