Tried to replace thermostat and one of the bolts snapped off
My car has 290000 miles.
My car has an automatic transmission.
Hi there. If the bolt is sticking out, then you can use a pair of vice grips to help remove the bolt or weld on a nut. If the bolt is broke off inside the threaded gallery, then you will have to drill out the bolt and use a tip to clean out the threads. Make sure that you put a rag in the thermostat flange area on the engine before drilling and remember to remove the rag when you are done. If you need further assistance with the broken bolt on you thermostat housing, then seek out a professional, such as one from Your Mechanic, to help you.