VT V6 Commodore Boiling over - Not overheating on temp gauge

[jaza-g]

Hi,
I have a commodore VT V6. Had a few overheating and weird issues with my cooling system since having this car (bout a year now).
It was a dual fuel from factory and I have removed the whole LPG system except computer is still factory.
I had a couple issues with radiator when I first got it so I decided to replace pretty much the whole cooling system.
What Ive done: New Radiator & Cap, Thermo and all radiator hoses. New Heater tap with hoses, New Water pump.
Flushed the system a few times. Recently noticed that it is boiling over without actually getting hot.
Thats what led me to replacing water pump for some reason, Just something I hadnt done yet.
Ive kind of thought it may be CTS (Coolant Temp Sensor) or something like that.
Today I took if for a small drive and then ran it in the driveway for a bit and noticed it was just boiling over and it wasnt hot in dash.
Temp in dash does start from Cold and goes up to just below halfway and pretty much stops (doesnt change).
Also, Fan in engine doesnt seem to be kicking in. Im too scared to run it too long to see if it is as it boils over before half way on temp gauge.
I havent noticed any coolant or oil leaks anywhere in the engine other than overflow when it is boiling over.
Recently serviced and the oil was a very normal colour, Not streaked with coolant or brown of any sort.
The coolant has had some weird brown flakes in it but thinking that may just be dirt from previously broken parts (ie. water pump was rusted as all hell when I replaced it).
Thoughts have crossed my mind it could be head gasket or inlet manifold gasket but hoping not.
Any ideas would be greatly appreciated.

Cheers
Jared

 

[dirty hands]

maybe a
radiator clogged or slow worn out engine cooling fan motor

did you bleed the air out of the system at the thermostat housing ?
i would check the inlet manifold gaskets for leaks ?

undo the battery terminals so you dont fry anything

wrap insulated wires from the battery terminals pos and neg unplug the fan connection and test the fans

air con fan works with air con switched on
engine fan clicks in through ECU
when you start the motor the engine cooling fan will click in and spin for a few seconds then stop
engine heat recognition needs it to start spinning

 

[jaza-g]

Removed entire LPG system bout 6 months, also didnt run on gas for years as it was my uncles car before mine.
Bled system at thermo housing when I changed water pump. (Yesterday)
The radiator is new, Gave it a flush yesterday and it ran clear.
Ive checked for leaks around IMG but doesnt seem to be leaking anything externally.
I will check engine fan with battery. Not sure if it even runs on start up for those few seconds now that I think about it.
A/C doesnt work so not sure if the fan is meant to work or not.
Thanks for advice, will get back to you once ive checked fan.

What do you make of it boiling over when the temp gauge still says under half??

 

[pebbs]

had the same problem with a VZ, new radiator cap faulty.

 

[lout]

what is leading you to believe it is boiling
is it leaking coolant from recovery bottle
making boiling noises
when hot can you touch radiator top hose or will it burn you. ie is the gauge reading close to actual
when engine is cold remove radiator cap-
is coolant to the top of radiator
start engine- are you getting bubbles coming up in radiator
fwiw my wifes vxii i noticed didn't sound the same normally can hear fan, found fan 1 was not working, car had not overheated and was reading about 1-2 mm higher temp on gauge than usual. fan motor had failed possibly several months ago

 

[jaza-g]

My mechanic actually advised that it may be the new radiator cap a few weeks ago as he said there have been some faulty ones.
So I bought a new High PSI one which seems great so far anyway.
Got the old/new standard one still. Dont believe it could be 2 different types of caps.

Leaking coolant from recovery/overflow bottle - Yes.
Steaming alot out of the overflow as well. Makes boiling noises yes.
When its running, (Mid range gauge temp), I can touch radiator cap and top hose (Holding pressure and a bit hot but not actually too hot to touch).
Since having this issue when I need to top it up (After "boiling over") the coolant is normally quite low in radiator needing more!!
When i refill it it and run engine then top up I dont get any bubbles in the actual radiator if thats what you mean.
I am going to check fan today and post results.

 

[jaza-g]

Ok, So fan doesnt start with car which I think it use to. Turning heater on full doesnt activate it either. (AC doesnt work, Did try it though to see if it kicks on fan but nope).
I will try unplugging battery harness's and wiring fan straight to battery to see if it works at all.

If fan does work straight through battery whats that telling me? Coolant Temp Sensor??
Maybe even just checking wires and cleaning plugs out. Fuses all seem ok.

If it doesnt work Im thinking new engine fan?

 

[devilly]

coolant temp sensor is around $30 easy job remove clip then unscrew the old one,screw in new one and put clip on i reckon it may be this due to the fact on start the gauge is reading warm when it's cold.

 

[wrx884]

do u actually have gas in the AC system? if not this test wont work and the fans wont turn on when u switch it to AC. Use the digital read out on the LCD screen and see what temps ur reaching. fan should come on around 104* mark for sure. if u go over that then theres an issue.

 

[lout]

i dont believe it is the temp sensor as gauge appears to be normal
as i mentioned earlier fan1 being faulty caused no symptoms at all
try buying another radiator cap at correct psi only $5
have mechanic pressure test cooling system and then start engine and see if pressure increases