I used some of the bars leak that works when mixed with antifreeze. It stop the smoke but the engine still runs bad and confirmed bubbles in the radiator while the engine was running. I know there is different types of engine block sealant. which is the best to use that will work the longest. I wont to know if the liquid glass type , copper type or ceramic type would be best to use.
The best by far is a cork or multi-layer style. It takes a touch longer to use than a BARS stop leak, but it's a much more permanent fix. It's called get a new head gasket. Those liquid based sealants just gum up your cooling system. So while the engine might run a little better since it won't leak coolant into the combustion chamber, it will, sooner than later, blow from overheating anyways since the stop leak will clog up the cooling system and cause the engine to overheat, and blow the gasket in another place or worse, warp the cylinder head.
Nicky, you have brought up two different issues and points. as a temporary fix till the head gasket is replaced a head gasket sealant or in correct term stop leak is used. bars leak is just such a product. I recommend on that point Allumaseal its a powder based product that you pour into the radiator and start and drive the car for at least an hour. the powder gets trapped in the leaking spots and clogs the spot for a while. now head gasket sealer, this is a product you coat the new head gasket with to insure a good tight seal when it is all installed. if the head gasket is a fiber type gasket like a thick cardboard I recommend coating the top and bottom of the gasket with a thick layer of copper coat. this comes in a spray or brush on and is applied just seconds before lowering the head in place. it seals well and helps keep the gasket in place as well. many newer head gaskets can be offered in a perma-seal design that require no additional sealers. I am a firm believer in adding insurance to any area's water passes through. a light film of sealer to those area's. One important point, if a head gasket is the question be sure, really sure that the head is not warped. this is when it is no longer totally flat and is caused by a combination of possible reasons. usually stretched head bolts and cylinder hydraulic lock from fluid entering the firing cylinder.
