rubber gasket shelf life
02-09-2020, 03:10 AM
#1
Racer
Thread Starter
rubber gasket shelf life
will be doing the head gakets on the SE around easter time and just noticed there is what looks like an expiry date on the parts sticker from Porsche for 1 of the cam cover gaskets, which expired in 2010.
it looks and feels ok to me and has been in dry storage.
what happens to unused rubber gaskets to make them not do their job after 5 years?
cheers
Phil
it looks and feels ok to me and has been in dry storage.
what happens to unused rubber gaskets to make them not do their job after 5 years?
cheers
Phil
02-09-2020, 09:43 AM
#2
Rennlist Member
Phil,
Rubber most certainly has a finite shelf life that varies with the type of rubber involved and the stuff used will probably have an official shelf life of 5 years. Oxygen is probably the most prominent degrading agent. The notion that the stuff is useless after 5 years and one day would be absurd. The problem is the manufacturers have no clue as to how the stuff is to be stored and what it will be exposed to. Ozone for instance really duffs up the shelf life so if the item is stored next to an electric motor logic says it would not fare well. So they stick a shelf life on the stuff knowing full well it will probably last much longer and it then becomes a matter of "cover your ***" for the supplier. Tyres are stored in a dark warehouses for similar reasons or so I understand. Rubber also likes to be flexed to keep the molecules liable- leave them static for long enough and the molecules start to crack when flexed.
If the gaskets material flexes without issue then personally I would not hesitate to use it- if it fails a cam cover gasket is not the end of the world to replace. For a timing belt I would be way more conservative.
For whatever little it may be worth, when I install mine I use some high temp silicon RTV in the trough and I have had mine out several times during my breather project mods- reused the same gasket every time and no leaks to date.
Rubber most certainly has a finite shelf life that varies with the type of rubber involved and the stuff used will probably have an official shelf life of 5 years. Oxygen is probably the most prominent degrading agent. The notion that the stuff is useless after 5 years and one day would be absurd. The problem is the manufacturers have no clue as to how the stuff is to be stored and what it will be exposed to. Ozone for instance really duffs up the shelf life so if the item is stored next to an electric motor logic says it would not fare well. So they stick a shelf life on the stuff knowing full well it will probably last much longer and it then becomes a matter of "cover your ***" for the supplier. Tyres are stored in a dark warehouses for similar reasons or so I understand. Rubber also likes to be flexed to keep the molecules liable- leave them static for long enough and the molecules start to crack when flexed.
If the gaskets material flexes without issue then personally I would not hesitate to use it- if it fails a cam cover gasket is not the end of the world to replace. For a timing belt I would be way more conservative.
For whatever little it may be worth, when I install mine I use some high temp silicon RTV in the trough and I have had mine out several times during my breather project mods- reused the same gasket every time and no leaks to date.