Carter Volkswagen Service FAQs: What Causes a Cracked Engine Block?
In a modern, well-maintained car, cracked engine blocks are virtually unheard of. That said, a crack that forms in the engine block can spell the end of your engine — because no permanent fixes are guaranteed. It's one of a very, very small number of repairs that might be impossible to truly fix.
The experts at Carter Volkswagen want to help you care for your car properly, and make smart decisions when it comes to the maintenance of your vehicle. Even if it has a cracked engine block. That's why we've compiled this page with all the information you need to know about cracked engine blocks — what causes the crack, ways that it can be fixed, and why these fixes can be so costly, difficult and unreliable.
What Causes a Cracked Engine Block?
In a word: Heat. Excess heat can cause the metal parts of your engine to warp, deform and eventually break and crack. The coolant system in the engine is designed to keep everything operating at a safe temperature that won't overstress the metal — but if something goes wrong with the coolant system, the engine may begin to overheat. You should notice a warning light in your dashboard (or a temperature gauge entering the red area) if this happens.
As soon as you see signs of engine overheating, be sure to pull over and allow the engine to cool as soon as possible! You'll also likely need a tow to a local Volkswagen authorized dealer for service. Operating an engine at high temperatures is a sure-fire way to end up with costly repairs like a blown head gasket, a warped cylinder head or a cracked engine block.
Can my Cracked Engine Block be Fixed?
In a word: Maybe. Because modern engine blocks are made from cast iron or aluminium (rather than a more welding-friendly metal like steel) weld repairs are typically impossible. To repair your cracked engine block, there are a number of exotic options that you could try. These include simple additives that are poured into the coolant system in an attempt to form a chemical bond from the inside of the engine that seals the crack. Or, a two-part epoxy could be used to seal the crack from the outside, or a number of other sealant products. Finally, cold metal stitching is a labor-intensive process that attempts to simulate repairing the crack like you would a tear in a piece of fabric.
Sadly, these repairs are often costly and may not even last you very long. That's because of the wide range of operating temperatures in your engine. At start-up, your engine is about the temperature of the outside air — and when running can reach up to 220 degrees safely. These radical temperature swings cause the metal to expand and contract, and will usually cause the original crack to reopen shortly after a repair is made.
Therefore, in the case of many cracked engine blocks, your most economical option to repair the car may be to get a full engine swap.