VT V6 Commodore Boiling over - Not overheating on temp gauge

[devilly]

i agree with lout,cheapest and easiest,borrow a mates cap thats know to work. only other thing is thermostat stuck.or the hose going back to reservoir bottle has and air leak.

 

[jaza-g]

I didnt say anything about temp being warm when started. It starts of at C (Cold) and slowly makes its way up to just before halfway where it stops and doesnt go any higher.
I will test CTS anyway as I have had issues in the past with them and this is kinda telling me the same info. Also, the CTS is much easier to replace on VT than my old cars (VN & VP).

AC hasnt been used in years so yeah pretty much a no go zone for me. Doesnt switch on or engage at all.
Didnt even think of using the digital, Thats a great idea. Thanks!

Ive mentioned before Ive bought 2 new radiator caps in the last month. Both with the exact same issue. One being the high psi one and one being standard.
New ones are pretty cheap so might just give that a go anyway when I get a new CTS.
Im thinking a trip to the mechanic might be the way to go, to diganose the situation.
I havent completely checked the fans yet, Ive had enough for today. Might get out there on the weekend and test the fan.

 

[devilly]

hang in there. i'm not good with the words but i'll try. you can test the cts i think its ohms or something, you put the black one on one pin and the red on the other and the reading will change as it gets colder.i found while holding it and putting it in the freezer if it didn't change or was very slow to change it was faulty.

have you had the engine light come on.thinking a fault code may stored in the computer.

 

[Nut Kracker]

Have you checked the fan's fuses, under the little black cover, in front of the battery, next to the top radiator hose?

Try unplugging the CTS.....Start the car.....Both fans "should" come on.
The reason the fans should come on, is because the ecu doesn't know what the coolant temp is.
So as a fail safe, if the cts or the circuit is faulty, it will turn on both fans, so the engine wont over heat.

You also could have a mass of air bubbles in the system.
This can be caused by not have a fully sealed and pressurised system.
If the cts is exposed to air in the system, it will read cooler than if exposed to coolant.
This could be the reason your engine seems to be boiling, but the cts is reading cooler than it actually is.

 

[jaza-g]

Ok. Thanks heaps for the advice guys.
Heres what I just did to the commy.

Unplugged CTS.
Started engine.
Fans started
Rules out fans not actually working.
Cut engine, plugged cts back in.
Started again in cop mode for digital temp.
Let it run for a bit to test fan.

Steam started coming out overflow at 101.
Let it continue til 104.
FAN KICKED IN right on 104. Was steaming out overflow the whole time from 101 to 104.
once fan kicked in it stopped steaming for a few seconds (temp went down to around 99) then started steaming again.
After turning off. It just steamed out overflow the same as it has in the past.
Is this saying that the cap is definently not holding enough pressure? I cant troubleshoot this issue for the life of me.
Atleast I think i know that the CTS is fine as the fan kicked in right on time. Engine doesnt feel hot at all, i can put my hand on the plenum and hold it there.

Top & bottom Radiator hoses didnt get too hot too touch. Held pressure and seemed ok.

Side note. Radiator cap sits nicely.
Has a great seal, doesnt move or wobble.
Havent got any mates with a v6 so might buy another one just to test.

 

[Nut Kracker]

If I start my car and let it idle up to N.O.T. (normal operating temperature), the engine doesn't get as hot to touch
as if I'd go for a drive and get it up to temp.
If you let it sit idling for long enough after reaching N.O.T. it eventually will get hot.
This is partially because the bonnet's open, letting heat escape from the block and exhaust.
And the engine is not under load. eg: working as hard.
So don't worry about that.

But if there is steam coming from the overflow, I'd say either the cap is cactus, or the cap has a too lower pressure rating.

 

[lout]

the radiator you bought
was it genuine, good quality aftermarket, or cheap ebay
i have found a few cheap radiators that can be temperamental to seal

 

[jaza-g]

The radiator. My mechanic did for me as I couldnt be bothered. Pretty sure he ordered it from Repco or Burson. Paid about $300 for just the radiator so I hope its a good one. I was looking at the ebay ones for 150 - 200 when I was going to do it myself but decided against it. Ive had 3 caps with all the same issue so it could be a possibility still. Is there a way of getting it to seal better maybe? I use to use cling wrap on my VN haha but was always scared i would blow something. Maybe I should give my mechanic a visit..

 

[devilly]

check the radiator when the cap screws on for any signs of damage.there is also a hose that goes from the refill bottle to the side of where the cap goes on if this is damaged it can suck air through the system.

brown chunks in the radiator also sounds like it might be descaling itself i think its called. which means a replacement radiator as the internals aren't holding the pressure.just back pressure through to the refill bottle.

did you bleed the air out of the system with the heater on full ?

 

[jaza-g]

I'll check where the cap screws on and that overflow hose for any signs of damage. Nothing that I've noticed lately. It is only 6 months old so I'm thinking if the radiators "descaling" or anything I'll be taking it straight back to mechanic where I got it done. I did just replace water pump which was rusted to the point of metal filings so probably from that.
Yeh always bleed it, I use a cut 2L bottle and undo bleed screw. Cheers for advice. I think I'm slowly getting there. Dont know if it could be anything else really other than faulty radiator or cap. Or even the overflow hoses. Thanks again.