Cars that suffer from chronic head gasket problems are astonishingly expensive to keep running. Consumer Reports has put together a list of the worst offenders by analyzing data from its Annual Autos Survey. There are four Subaru models on the list, several luxury cars, and, surprisingly, everyone's favorite Mazda roadster.
In simple terms, a head gasket is a part that ensures an engine's combustion happens internally. It's between the cylinder head and the engine block. Every car has at least one, and changing it is a time-consuming process that can cost over $1,000 depending on what you drive, the extent of the damage, and who you ask to fix it.
Consumer Reports found the BMW 3 Series from the 2006 and the 2007 model years experience head gasket trouble at anywhere between 90,000 and 138,000 miles. Subaru's Impreza (2006 to 2008 model year), Outback (2001 to 2009), and Forester (2001 to 2009) all develop head gasket issues between 90,000 and 163,000 miles depending on the year and the model. These cars use the same basic flat-four engine with two head gaskets, and owners who responded to the Annual Autos Survey said replacing them costs between $2,000 and $4,000. As depreciation inevitably takes its toll, changing the head gaskets can cost more than the car is worth.
Subaru's Baja also appears on the list along with the 2008 to 2010 Mini Cooper/Clubman (57,000 to 124,000 miles), the Chevrolet Cruze (62,000 to 97,000 miles), the BMW X5 (59,000 to 67,000 miles), and the Infiniti M. Finally, the publication also noted the second-generation Mazda MX-5 Miata is prone to head gasket failures. It added that, in some cases, it doesn't have enough data to accurately list the mileage issues occur at.
I own one — am I doomed?
Use this list as a resource when car shopping, or when planning your current car's maintenance needs for the year, but remember that where and how a car is driven can significantly affect the odds of blowing a head gasket. If you suspect something is wrong with your engine, or if you want to make sure you won't spend more on repairs than on your next used car, there are several ways to tell if a head gasket is about ready to call it a day.
Thick white smoke coming out of the exhaust is a sign of a head gasket problem; it means coolant is entering the combustion chamber and getting burned with the air-fuel mixture. An engine with a blown head gasket will often have a rough idle, and it will have a tendency to overheat even if it's not particularly hot outside or if you're not asking much of it. And, when in doubt, check the oil. Coolant seeping through a blown or leaking head gasket mixes with the oil and forms a mayonnaise-like substance that appears on the dipstick and under the oil cap. Its thickness and quantity largely depends on the extent of the damage. Condensation can cause that, too, so don't immediately panic if you look under the oil cap and see something that looks like it belongs on a sandwich.