blown head gasket on a 5ltr

[calais&statesman]

how can i tell if a head gasket has blown on my 5ltr, if i take the radiator cap of with the motor idleing coolant spews out the top, with the motor still running i tried topping it up but the water just keeps coming out the radiator, temp wise it stays between cold and half, any help please

[Pub247]

how hot is water coming boiling or not?

Sounds likeits blowing cylinder pressure into cooling system. If its not noiling over

[calais&statesman]

the water coming out as im filling it up is boiling

[Blown V6 Hatch]

What happens when you rev it up a bit with the radiator cap off?

Pretty uncommon for a stock EFI 5 litre to blow a head gasket.

[calais&statesman]

What happens when you rev it up a bit with the radiator cap off?

Pretty uncommon for a stock EFI 5 litre to blow a head gasket.

The water level drops and it stops boiling...

The Mrs bought me a gilmer drive kit for christmas, so I had to remove the clutch fan and replace it with 2 thermos, ever since then I've had dramas keeping it cool.

[Blown V6 Hatch]

Safe to say it's not a head gasket then.....If it was a head gasket, it would blow water out the radiator when you rev it up.

I'm thinking jammed/stuffed thermostat.

What fans are you running?

[calais&statesman]

ive got 2 ten inch {calibre brand} thermo fans, i did have one twelve in fan but that wasnt keeping cool either so i tried the 2 tens and that didnt help either

[Blown V6 Hatch]

EF-EL Falcon fans are the go mate. No dramas what so ever keeping my 5 litre cool.

Still think your thermostat could be stuffed though.

[calais&statesman]

nah its a brand new themostat and its ment to run it cooler, it opens at 180, and when i put it in last week it didnt help either, and your right about the ef el fans every one i spoke to said the same thing, cheers man

[Blown V6 Hatch]

Could just have some air left in the system from when you changed the thermostat then?

Is the heater hot?

[calais&statesman]

its got climate control and now you mention it, the heater does not get real hot, my girlfriend has got a vr 5ltr statesman with the same features as mine and her climate control on full blast is heaps hotter then mine

[Blown V6 Hatch]

The only other thing i can think of that Holden V8's like to do from time to time is the blades have corroded off the water pump impeller. Hence why i asked if the heater was hot, as cold/coolish heater = litttle to no water flow.

I'd probably pull the water pump off for a look.

[calais&statesman]

every now and then i can hear water running threw heater, next time i start it i will grab hold of the heater hose inside the car and see if there hot

[VR38]

Sounds like the new thermo fans are not upto the job.

[vl_nick]

The water level drops and it stops boiling...

The Mrs bought me a gilmer drive kit for christmas, so I had to remove the clutch fan and replace it with 2 thermos, ever since then I've had dramas keeping it cool.

I think this statement answers your own problem

[pow3rslave]

with the thermo fans, is there any shroud on the, or are they just bang on the radiator?
ideally you'd have a shroud/cover on the rest of the radiator so that air is drawn to and through the fan.

[vpshtb0x]

I think it may just be the fans but, may also be an airlock in the cooling system (is the system pressurising?). If it is an airlock, park your car on a hill so the nose is up then turn your heater on and top the radiator up while the engine is running.

[Warranty Void]

Search the threads for "mondeo thermo fan" the 304 radiator is too small for the au falcon twin thermos but the mondeo one is supposedly a spot on fit.
Radiator cap is also important, put a new one on if its suspect.
Remember to bleed the coolant system with the heater turned on full hot or you'll just get air pockets later and the heater wont work properly.
You must have a shroud with thermo fans on commodore v8's.

[GTP 85]

Long shot... but are your fans running the right way? Ive seen that mistake before