Hey guys,

Need a bit of help just really to see if we've diagnosed a problem properly as I'm not that familiar with Falcons. We were on our way to Albany from Margaret River and the engine cut out mid corner. I looked down and temperature was just in the red and the battery light was on. I got out, opened the bonnet, saw that the serpentine belt had shredded itself and heard a loud POP then all the coolant disappeared out of the expansion bottle so I assumed the headgasket had gone.

Since then, I've investigated and taken off the rocker cover, and the lifter assembly is pristine, with no water in the oil. Also the dipstick has no water in the oil and hasn't lost any oil. A core plug is covered in congeled coolant so I reckon that the pop was the water coming out of the core plug (it looks fresh).

The crank pulley is not in line with the rest of the pulleys (too far towards the rad), so I reckon I need a new harmonic balancer and this is why the belt shredded itself.

So, we're thinking that I might have gotten away and the headgasket is ok. Is this possible?

With the Crank Pulley being about 1cm nearer the rad than it should be - is this definitely the Harmonic Balancer? Prior to this, we did 5000kms with no worries and no symptoms.

I'll have to travel to bunbury (over 2 hours from where I am now - near Pemberton) to get the bits and at the moment, the parts list is:
Harmonic balancer
Serp Belt
Rocker Cover gasket
Core Plug
Coolant

Have I forgotten anything?

Check the heater hoses under the inlet manifold... Falcons are notorious for blowing them.

If you've done a Welsh plug get a whole set of them, if one has rusted out the others won't be far behind. Get brass ones.

I'll pick up a full set of welsh plugs so! How many altogether?

I'll check those heater hoses too.

Is there anything else I should check to see whether or not the head gasket is gone?

Take it to a workshop and get someone with the gear to look at it. Compression test, CO2 test etc... From my experience with these dungers, they run like crap when they do a head gasket. But I guess thats only if they let go between the cylinders. Doesnt take much for them to crack the head too when they get real hot.

I assume its not running at the moment.

But when you do get it going if its blowing a lot of steam out the exhaust its a good sign for a blown head gasket..

Or you can do a cylinder compression test.
and do a pressure test on the cooling system to see if their are more leakes you've missed. If its not holding pressure and its not visulay leaking its probably your head gasket.

When one of my belts snapped it flung around and hit the radiator. Cracking it open and took out some wiring aswell. So have a good look at your radiator. They are plastic on top and the crack in mine was hard too see without it running.

dazza - thanks for the suggestion, but it's not running so can't get it to a workshop without a tow.
87SIlude - I'll do a compression test as soon as I can, thanks for the suggestion.

Some further info - The welsh plug didn't pop out, but it was rusted to bugger. When I pierced a hole in it, lots of clean coolant came out with no oil. I checked the hose under the inlet manifold and everything looks fine.

So if it wasn't the welsh plug, or any hoses, what could it have been that I heard go pop?

I would definately replace the harmonic balancer! belt is a given too. I'd change all of the Welsh plugs now, and also change the rubber heater hoses. That should fix most of the dramas unless it is a headgasket gone. Also, don't forget the Welsh plug on the back of the block!

it sounds like the event went like this..
harmonic balancer has failed causing the serpentine belt to shred and come off,
which has caused the engine to overheat due to no water pump operating..
now you have shut the engine down which is the right thing to do,
but that boiling coolant is now pressurised and is still getting hotter.
it has to go somewhere so i say more than likely the pop you heard was the radiator cap releasing the hot pressurised coolant...

hopefully once you have replaced the welsh/core plugs and fixed the other bits it should be ok.
but there is a risk the gasket has now failed or head might have warped due to the over heating...

dont do just a compression test make sure you do a leak down test as this is an easier way of finding leaks any where

67RCE - Thanks for the advice! Do you reckon I should replace all of the heater hoses? I've checked all of the main ones and they're all perfect.

Troyman - That may be what happened. I thought the rad cap had opened first, but I was so p****d off that the rad cap opening could have been the pop! The engine actually shut itself off which was something I was a bit worried about! I think I might pick up a head gasket kit just in case!

RooseEL - thanks, I'll see if I can do that here!

Personally, it is worth the minor expense to replace the hoses now, while the cooling system needs attention. I'd also check out the heater tap as they are known to fail.