A sealing ring is a ring that is used to prevent leaks in pipes. A gasket serves the same purpose as a sealing ring, but can also keep in gas.
There isnt one. Replace the gasket. Additives are worthless. If you add something to your coolant to clog gasket tears then what else are you clogging?? Water pump, heater core, radiator? Replace the gasket.
A new head gasket.
Gasket that goes between head and valve cover to prevent leaks
Seldom, if ever, do i see a bad intake. On the older aluminum V-8 intakes in the oldsmobile engines they used a steel intake gasket and the steel would corrode pits into the sealing surface which caused antifreeze leaks. Most of the troubles that i see with intakes are with the intake gaskets going bad or with vacumn leaks caused by split vacumn hoses or a leaking intake gasket.
Depending on what engine you have, Intake manifold; vacuum leaks, coolant leaks internal and/or external, oil leaks. Exhaust manifold; exhaust leaks, backfires.
When it leaks.
Oil/antifreeze mix is usually caused by head gasket leaks or valve cover gasket leaks.
A failed head gasket will have different symptoms depending on where the gasket failed. If the gasket fails in such a way that coolant leaks it usually leaks into the oil reservoir and the oil will appear a milky light tan color. The coolant also may leak out of the gasket onto the engine, appearing between the head and the block. If the gasket leaks in such a way as to cause loss of compression the engine will idle rough or will not want to idle at all. If the gasket leaks oil it may end up in the cylinder(s) or come out between the head and the block. Also, any combination of the above described leaks may happen in conjuction with one another.
White smoke coming from the exhaust is a sign of a bad head gasket. There are some products that you can try for a blown head gasket but they are only good for small leaks. You will probably have to remove the head and replace the head gasket.
A common cause of problems in cylinder head gaskets is leaks in the gasket. When a leak forms, the gasket must be replaced.
You have a failed gasket, seal, or hose.