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Overheating VT Commodore - V6

Started by MRLXSS , Jul 26 2010 01:17 PM

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68 replies to this topic

#26 TerrA LX

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Posted 27 July 2010 - 12:26 PM

pumps either flow or don't.
Next time that happens check if the top hose is hotter than the bottom;
High difference in temp: >10C inadequate flow
Low difference in temp <10C adequate flow.

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#27 MRLXSS

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Posted 27 July 2010 - 12:39 PM

pumps either flow or don't.
Next time that happens check if the top hose is hotter than the bottom;
High difference in temp: >10C inadequate flow
Low difference in temp <10C adequate flow.

Will do! That should be noticeable by touch i guess. I know the top hose is never normally too hot to touch (hot but not scorching) Haven't tried the bottom one.

It's down at the radiator place now, he was stumped by it as well. When he released the pressure from the cap, a litre or so of water overflowed from the overflow bottle. He was suss about the thermostat (thought i was dumb and installed it wrong... But i had it in there correctly).

New cars suck! My Torana never has a problem like this! The 4 core keeps it NICE AND COOL!!!!

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#28 MRLXSS

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Posted 27 July 2010 - 03:20 PM

Radiator mob reckons head or head gasket.. Would this create these symptoms?

Even though i replaced both not all that long ago... Could they go again so suddenly?

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#29 _1uzbt1_

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Posted 27 July 2010 - 03:33 PM

your symptoms are very much like a air lock, if the heads are gone it quite possible it filling the system with exhaust gas and pushing out the coolant and then giving your air lock symptoms.Rad place may have a tee-kay tester to test for leaking head gaskets, ask them.

If its a recovery cap it will have a large rubber seal directly under the cap,non-recover has a brass ring instead of the rubber.The brass ring wont seal well enough on the top of the filler neck to be able to draw back coolant,yours sounds like the recover cap.

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#30 TerrA LX

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Posted 27 July 2010 - 03:48 PM

Yeah, could be head gasket, did you re torque the heads?

Maybe a re torque and can of chemi weld might catch it, follow the directions closely and flush the system afterwards and fit a new cap, after the chemi weld as it will block the cap some what as well.

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#31 MRLXSS

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Posted 27 July 2010 - 04:03 PM

Yeah, could be head gasket, did you re torque the heads?

Maybe a re torque and can of chemi weld might catch it, follow the directions closely and flush the system afterwards and fit a new cap, after the chemi weld as it will block the cap some what as well.

Ahhh, No I didn't... Never even thought about that. That would make more sense than the gasket just letting go again on its own... I'll look into it and see... Thanks for everyones advice and help so far! It's all helping make sense of the situation!

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#32 mr5000

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Posted 27 July 2010 - 06:53 PM

whose torque wrench did ya use migh have been out of wack i no mine is perfect its a snap on one and has been calibrated your welcome to borrow it if you like

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#33 _SS Hatchback_

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Posted 27 July 2010 - 09:07 PM

I kindof eliminated the head gasket when you said in the first post someone had pressure tested it i thought it would have shown up ?? I know my mates shows it ..

Did the other heads need machining at all? Where did you get them from?

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#34 _Woodsy_

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Posted 27 July 2010 - 10:37 PM

If its losing coolant its gotta be going somewhere, how much did you put in initially? What colour is the oil?

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#35 rodomo

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Posted 27 July 2010 - 11:01 PM

Is there a mist out of the exhaust even after it's properly warmed up?

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#36 _Brad1979UC_

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Posted 28 July 2010 - 01:06 AM

My Torana never has a problem like this! The 4 core keeps it NICE AND COOL!!!!

Absolutely, 4 cores for good measure!!

Are the water pumps on an ecotec alright to change? Much swearing involved? There's alot more pulleys infront of them i've noticed. Hopefully you can sort it out interested to see what it comes down to

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#37 S pack

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Posted 28 July 2010 - 01:28 AM

Hi Matt

Been pondering your cooling system problem. From what you have described it sounds like the engine is not actually overheating and boiling. The rapid gauge fluctuation and high readings will most likely be a faulty temp sender or gauge unit or ECU as others have already said.

One question. Does the car have standard Air Con or is it Climate Control Air Con? If it is the latter type then the ECU is probably automatically turning off the heater in an attempt to keep the cabin environment at the set temperature, based on incorrect information being supplied by a faulty engine temp sensor or as above the ECU is faulty.

Hope this helps
Cheers
Dave.

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#38 TerrA LX

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Posted 28 July 2010 - 11:12 AM

Hahaha, mechanic wants $2500 to do head gaskets and replaces temp sender, nothing shonky there.

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#39 S pack

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Posted 28 July 2010 - 12:37 PM

Hahaha, mechanic wants $2500 to do head gaskets and replaces temp sender, nothing shonky there.

Trouble is some repairers (brand name dealerships included) just rush in and replace stuff without doing proper diagnostic testing first, which can end up costing you heaps for work that wasn't necessary and didn't solve the problem. They just tell you the part was going to fail anyway so needed replacing or they don't replace the part, clean it up a bit and tell you they did.

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#40 _Woodsy_

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Posted 28 July 2010 - 12:58 PM

hmmm doesnt explain the loss in coolant though

Edited by Woodsy, 28 July 2010 - 12:59 PM.

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#41 TerrA LX

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Posted 28 July 2010 - 01:30 PM

Pull your plugs and have a look, if it is one cylinder sucking coolant then surely that plug will look different to the rest.

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#42 _Gunmetal LH_

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Posted 29 July 2010 - 04:22 PM

Can't remember the specs but the inlet manifold bolts torque setting is literally bugger-all. Overtighten and the gasket's crack and could be letting coolant into the cylinders.

The pressure may be fluctuating as it builds and then leaks-drops-possibly boils for a sec and builds pressure again until it leaks-drops pressure...

TerrA LX: "Pull your plugs and have a look, if it is one cylinder sucking coolant then surely that plug will look different to the rest."

+1

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#43 MRLXSS

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Posted 29 July 2010 - 04:29 PM

Problem is plugs are brand new... So won't be showing much... I will pull them out tomorrow and have a look though.

I have tomorrow off work so i'll be able to spend some time on it... HOPEFULLY fixing it!

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#44 _Gunmetal LH_

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Posted 29 July 2010 - 04:51 PM

I think the manifold bolt torque is 12ft/lbs.

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#45 MRLXSS

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Posted 29 July 2010 - 04:59 PM

Yeh, i do remember them being really low... It's something worth checking...

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#46 TerrA LX

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Posted 29 July 2010 - 07:09 PM

Problem is plugs are brand new... So won't be showing much... I will pull them out tomorrow and have a look though.

New plugs. Even better.

Just remembered too that these motors have bad problems with corrosion on the inlet manifold around the coolant ports, worth checking.

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#47 MRLXSS

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Posted 29 July 2010 - 08:52 PM

When i had the manifold off before, the manifold was still in perfect nick... I carby cleaned the whole lot up and made it look like new!

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#48 TerrA LX

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Posted 29 July 2010 - 09:08 PM

a "warm" compression test should eliminate head gasket and head cracks, but take care on the spark plug threads when removing once hot, don't want to strip one.
Maybe remove the plugs when cold, do a comp test first to check the results, put the plugs back in half torque, warm the motor and remove and test again, in general it is advised against removing plugs from a hot motor to save the threads in the head, especially on alloy heads.
Warming the motor may open up a crack or gasket if not showing on a cold test.

A re torque of the head gaskets would not go astray too.