I have a 2004 Chevy Aveo which I maintained regularly synthetic oil changes and all required maintenance. But one day the car starting making a weird noise from the engine when the A/C was on. Later that week that noise increased to sound like something was knocking and fuel consumption increased. I had a mechanic check it out and he says one of the cylinders has no pressure due to a stuck exhaust valve and that probably the rest of the valves are not looking good as well, because when he took the Spark plugs there was all kinds of junk on it, black carbon on them.

The heads to rebuild them are costing me $800 + tax, the labor to install them is cheap because I got a mechanic I've know for a long time, so he is charging me $400 to install, at service shops they want close to $2000 + to do this.

I don't know if this has damaged internal engine parts so it might be more expensive if I need a new engine. used engines are like $1600, rebuild engines are like $2500 + tax and labor is probably another $2000.

This is definitely a manufacturers issue since the valves don't seal properly since the car was new, this car has always burned oil and got the spark plugs fouled up pretty bad.

My 5 yr loan was paid up one month ago and the warranty on this car expired on that day. I was driving to work and out of nowhere the car bucked and did nothing when you stepped on the gas pedal and then kicked back it but wasn't running right. I had AAA tow the car to a private shop and the changed the wires and plugs to the tune of $331.00. The car still wasn't running right and they told me to take it to the dealer. There is a service bulletin about this car coding for certain things, which included the timing belt, and that was changed months ago. The dealer is telling me the cylnders, cylinder head and valves need to be replaced and it cost about $2400 plus I had to get a rental car. The dealer has had my car for 4 days already and today told me the cylinder head has to come from Canada so it's going to be next week before I can get my car back. They have no explanation why my car would be perfectly fine one minute and then have such a costly repair the next. It's "internal" they told me. This car has never given me a problem in 5 years, except having the thermostat housing replaced about 6 months ago. That was covered under my warranty. The dealer said this should not have happened to my car with only 71,000 miles on it. I had it serviced regularly - fluids checked, oil change, etc.