Gratuliere zum Erfolg! Übrigens: es wird empfohlen (allpar.com), im Kühlwasser IMMER eine Chemikalie zu haben, die Risse stopft. Das darf aber NICHT das Dichtmittel sein, daß Marco verwendet hat, weil es sich nicht mit dem Frostschutz verträgt (soll klumpen). Hier ein Bericht über die Anwendung der amerikanischen Version "Block seal" : Fixing Head Gasket Leaks and Small Cracks courtesy of Steve Richfield There are now several new "Block Sealer" products out with sodium silicate in them, the most popular being the K&W brand. The alchemists called sodium silicate "water glass" since it turns to glass when dried. When added to coolant, first it is sucked into a crack by the intake suction, then the exhaust blast dries some of it out and turns it to glass, making the leak smaller. This continues with each stroke, the leak getting smaller and smaller as concentric layers of glass are laid down, until the leak stops leaking. Genuine MOPAR antifreeze, recommended in Chrysler owners manuals, contain a small amount of sodium silicate to stop internal leaks as they develop. Hence, leaking head gaskets and cracked heads are usually only a problem if you haven't been using genuine MOPAR antifreeze as Chrysler recommends. Sure you have them, but you never have cause to know about them. In one extreme case, a friend had a car that was so bad that water trickled out of the tail pipe as he added it to the radiator. Treatment as instructed on the can didn't work. Then he decided to just leave the treatment in the engine rather than flushing it out as directed, as he lived in California where he didn't really need antifreeze. He drove the car without further problems for the next 2 years, whereupon it was totaled in an accident, with the block sealer still holding. Of course, things are never quite that simple. Here are the major complications: 1. Most products add metal to the mixture to strengthen the glass, so that it is more durable. Products without metal produce a "town car" result, where the fix may only last a year or so, provided that you don't take it on the highway and heat it up. 2. They often clog up the heater cores, so it is best to disconnect the heater when treating the car, and for a period following treatment. 3. As indicated on the label, it is very important to flush all of the antifreeze out before treating, and flush all of the block sealer out before replacing the antifreeze. I reuse the old antifreeze for a few hundred miles, then flush and replace it and reconnect the heater. 4. I believe that you should drive the car hard during treatment, to get the the crack to shift in any way it can to fully fill it in. However, I first drive gently to mostly seal the crack, then vent any gas in the head, then put the pedal to the metal to finish the job. I suspect that the Higway Patrol wouldn't let them put this on the can. Feedback by Alex Chan I wish to thank the CRC Industries, Inc. for developing this wonderful product, Permanent Metallic(tm) Block Seal. I have used this to seal my head gasket leak and it works great. Following the easy instructions from the block seal tutoring website, this product did the job. It saved me from an enormous expense of a head gasket replacement. The label in the Permanent Metallic(tm) Block Seal container said "Do not add anti-freeze." People reading this would not buy it without knowing that you could add anti-freeze after sealing has been completed. To be more accurate, "Do not add anti-freeze until sealing has been completed. Please follow the sealing instructions through our website, www.crcindustries.com/crcweb ."