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VS Head Gasket or LIM?

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Howdy all,

Ive a VS V6 Sedan L36.Runs with a miss after reaching operating temp.A small amount of bubbling in the reservoir after switch off but not before.Some smoke but cant confirm its colour as haven’t seen it in daylight yet,and its heavier after reaching operating temp.No coolant in the oil is visible on cap or dipstick but hasn’t been driven much since it happened.I will do a compression test and inspect the plugs but wanted to know is this how i differentiate between head gasket or inlet manifold gasket?

Any advice is appreciated.
 

rickybobby

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sounds like you're on the right track

inspecting the plugs and compression testing is generally not too difficult and could give you some more clues before you go any further

bad compression test results could confirm head gasket problems but won't necessarily rule out LIM
...but good compression test results don't necessarily rule out head gasket (or LIM either)

Attached head gasket failure type image is a neat summary of some possibilities in principle

As suggested LIM is a common issue and it's often easier and cheaper to replace that and then go from there if that doesn't fix the problem(s)
 

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Joined
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Messages
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Age
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Location
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Vs Ute
sounds like you're on the right track

inspecting the plugs and compression testing is generally not too difficult and could give you some more clues before you go any further

bad compression test results could confirm head gasket problems but won't necessarily rule out LIM
...but good compression test results don't necessarily rule out head gasket (or LIM either)

Attached head gasket failure type image is a neat summary of some possibilities in principle

As suggested LIM is a common issue and it's often easier and cheaper to replace that and then go from there if that doesn't fix the problem(s)


Cheers,that diagram is good information,will keep for future reference.Appreciate all the advice.
 

Lex

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Howdy all,

Ive a VS V6 Sedan L36.Runs with a miss after reaching operating temp.A small amount of bubbling in the reservoir after switch off but not before.Some smoke but cant confirm its colour as haven’t seen it in daylight yet,and its heavier after reaching operating temp.No coolant in the oil is visible on cap or dipstick but hasn’t been driven much since it happened.I will do a compression test and inspect the plugs but wanted to know is this how i differentiate between head gasket or inlet manifold gasket?

Any advice is appreciated.
Have a look under the radiator cap, any sludge?
Also look under the oil cap, again any sludge? If there is sludge under either or both, good chance its the lim gaskets.
 
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Have a look under the radiator cap, any sludge?
Also look under the oil cap, again any sludge? If there is sludge under either or both, good chance its the lim gaskets.


There is no sludge.The miss started not long after i flushed the heater core.My first train of thought was I’d left an air pocket in the system and blown the head gasket.

Appreciate the advice.
 

Lex

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There is no sludge.The miss started not long after i flushed the heater core.My first train of thought was I’d left an air pocket in the system and blown the head gasket.

Appreciate the advice.
Try bleeding the system again with the heater temp set to hot.

May got some water on plug leads that go to coil packs, or somehow on the dfi?

Checked the leads & plugs? All the easy stuff first?
 
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Try bleeding the system again with the heater temp set to hot.

May got some water on plug leads that go to coil packs, or somehow on the dfi?

Checked the leads & plugs? All the easy stuff first?


Cheers for that.If i had got water on leads or dfi would the miss show up all the time though.This miss doesn’t begin until operating temp reached.
 

Lex

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Cheers for that.If i had got water on leads or dfi would the miss show up all the time though.This miss doesn’t begin until operating temp reached.
Vacuum leak?
 
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