Cooling Issues

[Jimmy1]

Hello, i have a 2006 VE V series commodore (duel fuel) that is having issues with its cooling. A few weeks ago i was driving for about 3 hrs straight in 40 Degree temperature when all of a sudden my heat gauge went from a touch over 1/4th hot to right on H in the space of 2 minutes. I pulled over to let the car cool down to realise that there is a massive puddle of water on the right hand side of the car and the sound of the water bubbling in the radiator. I managed to refill the radiator and drive the car for another 2 weeks without any issues. The radiator stayed full over this period and i had no issues. Just the other day i was driving for 25minutes in 35 degree heat and all of a sudden the same thing had happened. the temperature gauge went from just over a quarter hot to right up on H within the space of a few minutes. So i got out the car again to find that the exact same thing has occured. There was a big puddle next to my right hand tyre and the engine was very low on coolant again. I refilled it and decided to head back home as i didnt want to risk cooking my engine. just before i got home the exact same thing happened again, so i pulled over and yep, another puddle of water. however this time when i took the radiator cap off to refill it, the cap snapped. It is also worth noting that during all these situations i only had the aircon on rather low and then not at all after the overheating parts.

My car has done 140,000km and has been serviced and regularly maintained. Any suggestions as to what the issue could be would be greatly appreciated. (Also ive read that a faulty radiator cap can cause pressurization issues in the cooling system. My cap does seem a little dicky compared to other radiator caps that i've used in the past.)

Cheers, Jimmy.

 

[ozNick]

Plastic radiator caps become brittle and die causing issues. I had a similar issue with the VZ.
Replace it and see how it goes, but carry water with you just in case.

 

[Micaxe]

I had similar issues also with my VZ, mine had an airlock, find it by touching the bottom hose, (will be a lot cooler than expected) & it pushed the water out of the tank. A new pressure cap on the engine should help. When refilling make sure to bleed all air from system

 

[Nitro_X]

My SV6 has the alloytec engine with the plastic coolant cap, although I haven't had any coolant loss or over heating issues, two services ago, they had trouble unscrewing this cap and eventually it cracked on removal and required replacement.

I've noticed since, when checking it myself that at certain points when re-screwing the cap that it's VERY tight, almost like it is cross threaded but I've checked both threads carefully, even with a magnifier and they look ok.

I reckon there is a design/manufacturing/engineering problem with this cap where the thread alignment is faulty or incorrect and doesn't completely align properly with the thread on the engine and when unscrewed may not be refitted properly if not careful.

 

[Nitro_X]

ps
You're supposed to check the coolant level via the reservoir and also top up from there if needed.... not via the coolant cap on the engine

The access on the engine is for when the system is flushed and refreshed with new coolant, but obviously it would be prudent to check this cap during a routine service too.

 

[Jimmy1]

Is it normal for the reservoir to leak when you fill it up? i assume its an overflow point.

 

[Nitro_X]

pps
I just had a cruise on ebay regards these caps and one supplier says there are two types, depending on the VIN reference number
My MY07 alloytec is the "CX"
*these are the non genuine part*

Tridon Radiator CAP CX18125 Holden Commodore VZ VE V6 Alloytec | eBay

Tridon Radiator CAP CW18125 Holden Commodore VZ VE V6 Alloytec | eBay

 

[Micaxe]

ps
You're supposed to check the coolant level via the reservoir and also top up from there if needed.... not via the coolant cap on the engine

The access on the engine is for when the system is flushed and refreshed with new coolant, but obviously it would be prudent to check this cap during a routine service too.

That's the pressure cap that may need replacing! If an airlock is present, it will not draw water back in to system.

 

[Benboy]

If there are NO obvious leaks, suggest that you start with a reputable Cooling Specialist who can pressure test your system. It should reveal any obvious problems. Might also pay to have the system pressure flushed and new coolant installed - if it hasn't been changed recently.

 

[aunto]

I had the same issue after a radiator flush after i bought the sv6 on 170k milage. Got the genuine cap from holden for $20 and changed the thermostat, all good now