Diagnosing a Cracked Cylinder Head

Series Summary

Whether or not you are a mechanic, you most likely have experienced that feeling of hopelessness when the body shop manager breaks you the news. What you had hoped would be a hole in the muffler or a bit of water in the gas turns out to be a repair costing hundreds--if not thousands--of dollars. At least that’s what the body shop manager tells you. The hours tick past as you wait for your ride to get fixed and you start to wonder if perhaps this particular business might have exaggerated their estimate just a bit, maybe enough for a new stereo or a trip to Cancun. But how can you be sure? The solution is to know more about your car and what can go wrong with it. In this free auto repair series, Expert Village examines one of the costliest car repairs, so watch and learn what to look for so you don’t get taken advantage of next time at the repair shop.

Doug Jenkins has seen many a cracked head in his time. Damaged cylinder heads are a constant risk in the hot rods which his body shop specializes in: push a car to the limit on the race track and it may show signs of stress and strain. Doug tells you what signs to look for if you think you might have a cracked head. Does the antifreeze level go down too fast? Notice anything unusual about the oil color or hose pressure? Check all of the warning signs first, because actually getting to the cylinder head is a very complicated process, which involves removing everything from the v-belt and ac compressor to the intake manifold and headers. But Expert Village takes you every step of the way.

Video Transcript

"DOUG JENKINS: Hi. I'm Doug. I work with 20 great guys in St. Louis at Doug Jenkins Custom Hot Rods, and we're going to do some work for you today on Expert Village. This '73 Mustang has an engine problem. The customer complained of poor running and he kept having to add coolant and then, when he finally gave up, it had lots of white exhaust. So it sounds to me like either a bad head gasket or a broken cylinder block. We're going to tear into this car and find out exactly what. This car is fuel injected; it should start real easy. You just reach in the window and turn the key. Apparently, it is running badly. Right now, it doesn't sound so bad. Let's pour coolant in it and see what it does. Do you have coolant? I don't see any coolant in it at all. We're going to grab some coolant and put it in here. It has a reservoir on the side. It's empty, which indicates to me that it is sucking coolant out."