Blown head gasket and compression loss?

[MudRunnerTD]

G'day guys,

I have a mate who drives an 80series (I know right !!) it has a 4.5 petrol and he has blown the head gasket.

It started over heating and he has continued to limp it around for the last month.

So chatting via text he has described the following:

The car won't drive over 40km/h. As soon as it hit 40 the engine shuts down. The compression just drops right out of it. It does not overheat any more but it did when it first blew. The radiator looses all fluid and the oil has white paste.

It sounds like there is more trouble than just a cracked head??? Can anyone confirm this for me? He is interstate and has limited access to a decent mechanic and funds.

Thanks guys.

[BigRAWesty]

On gas??
Typical 80 4.5 thing if On gas..
Head is usually fine, gasket just blows..
Good time to fit decent valves if it's gas also..

[MudRunnerTD]

Would it loose compression like that though?

[MudRunnerTD]

Yep on LPG and plays up the most on LPG but now loosing compression on Petrol too.

[Alitis007]

G'day guys,

I have a mate who drives an 80series (I know right !!) it has a 4.5 petrol and he has blown the head gasket.

It started over heating and he has continued to limp it around for the last month.

So chatting via text he has described the following:

The car won't drive over 40km/h. As soon as it hit 40 the engine shuts down. The compression just drops right out of it. It does not overheat any more but it did when it first blew. The radiator looses all fluid and the oil has white paste.

It sounds like there is more trouble than just a cracked head??? Can anyone confirm this for me? He is interstate and has limited access to a decent mechanic and funds.

Thanks guys.

First he needs to see where the water is going, if its not leaking out of a hose then he has to eliminate it going into a cylinder. He can make a tool with some plastic tubing to put in the radiator neck that he can fill half way with water and crank the engine ( with the coil disconnected ) and see if it rises. If it does rise he has to remove 1 spark plug at a time, crank and see if the water level rises or lowers till he pinpoints which cylinder is at fault. If the water is going into the oil the oil level will be high as and will be a latte type of color and mixed throughout the motor ( see from the dipstick ) and not just under the cap.
Its not uncommon for the heads to crack thats why some mobs that do change over heads drill the water jackets and fit a bleeder system to the top hose, i've fitted one to a family friends 80. The other cause for the over heater is to get the radiator cleaned with the tanks off and to check the thermostat.

Without seeing the car mate and feeling what it does over 40 its hard to say why it cuts out. Rekon you could text me a video of him driving it and cutting out ??? And that head test should only be done with the motor dead cold.

[MudRunnerTD]

Thanks George,

He has been driving it for a month or so like this and its getting worse, I am concerned about big end bearing damage now. What are your thoughts? I have forwarded your response to him via text too mate.

He is over in Adelaide and the timing for this could not be worse.

I will see if he has the tools and know how to do the tests you have described mate, cheers. Pointing him towards an engine swap at this stage though I reckon. What are your thoughts on that? The economics of chasing potentially significant damage versus Swapping it out? What are your thoughts?

[MudRunnerTD]

First he needs to see where the water is going, if its not leaking out of a hose then he has to eliminate it going into a cylinder. He can make a tool with some plastic tubing to put in the radiator neck that he can fill half way with water and crank the engine ( with the coil disconnected ) and see if it rises. If it does rise he has to remove 1 spark plug at a time, crank and see if the water level rises or lowers till he pinpoints which cylinder is at fault. If the water is going into the oil the oil level will be high as and will be a latte type of color and mixed throughout the motor ( see from the dipstick ) and not just under the cap.
Its not uncommon for the heads to crack thats why some mobs that do change over heads drill the water jackets and fit a bleeder system to the top hose, i've fitted one to a family friends 80. The other cause for the over heater is to get the radiator cleaned with the tanks off and to check the thermostat.

Without seeing the car mate and feeling what it does over 40 its hard to say why it cuts out. Rekon you could text me a video of him driving it and cutting out ??? And that head test should only be done with the motor dead cold.

Cheers again George,

He will shoot a vid tomorrow mate and ill send it too you.

Cheers bud.

[Alitis007]

Thanks George,

He has been driving it for a month or so like this and its getting worse, I am concerned about big end bearing damage now. What are your thoughts? I have forwarded your response to him via text too mate.

He is over in Adelaide and the timing for this could not be worse.

I will see if he has the tools and know how to do the tests you have described mate, cheers. Pointing him towards an engine swap at this stage though I reckon. What are your thoughts on that? The economics of chasing potentially significant damage versus Swapping it out? What are your thoughts?

If he hears a knock on start up then yeah swapping the motor out is the best option but if the oil is over full and hes getting the big end slapping the the oil he needs to drain some out and test again. Problem is if he gets a second hand motor whats not to say it has the same problem, you only get 30 days warranty, if your lucky up to 90 days so i always recommend reco'ing the head. BUT and this is a big but, if the motor used oil or had a slight knock you would look at other motors. The other thing too is if the motor has overheated too many times and the alluminium of the head is too soft he has to see how that will affect the cost of the head.

Before we make anymore assumptions lets figure out what the fault is because there a couple of other things you need to factor in, so before we start talking head or motor let know for sure what we're dealing with then we can try and weigh up the options.

[Alitis007]

Btw Darren i should have said to make that tool with clear plastic tubing otherwise you won't be able to see whats happening to the water level

[BigRAWesty]

My bro is a mechanic over in Adelaide and a bloody good one at that.. And owns an 80..
Ill see if he's keen for beer currency to diagnose..