Having crankcase ventilation valve problems with my 2015 Holden Astra

Having a bolt snap off while you’re undoing it is a royal pain and can bring take the car off the road if it’s a critical fastener. You’re probably best off visiting a mechanical engineering shop (or good workshop) who will have the tools necessary to remove the broken chunk of bolt still lodged in the car.

Techniques vary according to how much bolt is still showing, access to it and even what it’s made from. In some cases, the engineer will use what’s called a bolt-extractor kit which screws into the broken bolt and extracts it without damaging the existing threads. If you’re lucky there will still be enough of the broken bolt exposed to allow the use of vice-grips to remove it. Sometimes a small section of new metal can be welded to the broken stud or bolt to give purchase and in extreme cases there’s even a process called spark eroding which is more expensive but can really save the day. The last resort is usually drilling the broken bolt out as this can destroy the threads in the part, requiring even more work to ultimately replace the fastener. In each case, penetrating fluid and/or the application of heat will be the first step to try to free or loosen the broken fastener before trying to extract it.