S2/968 head gaskets
Discussion
What's the opinion here about the need to change the head gasket on these engines? I understand that issues with rotting gaskets allowing the coolant to 'short-circuit' and overheat the rear cylinders has been identified as a weakness and potential seriously expensive damage occurring if not sorted quickly!!
Looking at a 968 that is 21 years old with 114k miles and has never had a replacement but the compression test indicates all well and the opinion of a well known specialist is don't touch it until it shows signs of failure. Fair enough but does that mean constantly having to test the engine temperature, front to back, with an infrared thermometer??
Looking at a 968 that is 21 years old with 114k miles and has never had a replacement but the compression test indicates all well and the opinion of a well known specialist is don't touch it until it shows signs of failure. Fair enough but does that mean constantly having to test the engine temperature, front to back, with an infrared thermometer??
Thanks for all the opinions and advise.
Have researched further and found two well known specialists (Hartech and JMG Porsche) agreeing on the need to change head gaskets on a 10-12 year cycle to prevent potentially catastrophic failure.
This is what Barry Hart has said on the matter;
'In my experience - 10 to 12 years is the safe maximum for this head gasket - not so much to the point that it no longer seals the compression - but to an age at which it will start short circuiting the coolant and run the risk of local overheating. Age is the main cause as the coolant remains in contact with the gasket when you are not using the car.'
And Jon Mitchell's comment;
'The head gaskets on these tend to be in tip top condition when changed at 5 years, however at 10 years old they are beginning to become brittle, after 20 years they might be hanging on for dear life and still sealing, but when they finally fail, they fail in a big way. So my usual recommendation with head gaskets is usually to change them if they are over 10 years old.'
I realise there will be many folk who strongly subscribe to the view that it is unnecessary until it fails, but where do you stop with this philosophy? Wait 'til the tyres fall off the rims even though there is plenty of tread left, for instance??
As has been mentioned above if the head gasket is changed during a 'major' service then the additional cost of preventing a failure is considerably cheaper and gives an opportunity to check the condition of valves, guides, etc. for further peace of mind (or potentially more expense!).
As always, it depends on how you intend to use your car which ultimately decides on the course of action and if it is only a couple of thousand miles a year of local driving then the need to do this will be low down on the list.
Have researched further and found two well known specialists (Hartech and JMG Porsche) agreeing on the need to change head gaskets on a 10-12 year cycle to prevent potentially catastrophic failure.
This is what Barry Hart has said on the matter;
'In my experience - 10 to 12 years is the safe maximum for this head gasket - not so much to the point that it no longer seals the compression - but to an age at which it will start short circuiting the coolant and run the risk of local overheating. Age is the main cause as the coolant remains in contact with the gasket when you are not using the car.'
And Jon Mitchell's comment;
'The head gaskets on these tend to be in tip top condition when changed at 5 years, however at 10 years old they are beginning to become brittle, after 20 years they might be hanging on for dear life and still sealing, but when they finally fail, they fail in a big way. So my usual recommendation with head gaskets is usually to change them if they are over 10 years old.'
I realise there will be many folk who strongly subscribe to the view that it is unnecessary until it fails, but where do you stop with this philosophy? Wait 'til the tyres fall off the rims even though there is plenty of tread left, for instance??
As has been mentioned above if the head gasket is changed during a 'major' service then the additional cost of preventing a failure is considerably cheaper and gives an opportunity to check the condition of valves, guides, etc. for further peace of mind (or potentially more expense!).
As always, it depends on how you intend to use your car which ultimately decides on the course of action and if it is only a couple of thousand miles a year of local driving then the need to do this will be low down on the list.
Edited by yknot on Tuesday 23 September 14:30
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