If your car is losing power and the motor isn’t running smoothly, the engine may have “burned values.” If so, this typically requires a major engine repair, or possibly a complete engine rebuild. A “burned valve” is one that has overheated and lost its ability to hold a leak-free seal. Value burning is usually limited to exhaust valves because they run much hotter than intake valves.
There are several reasons why valves burn:
- Normal use--The constant pounding and thermal erosion wears away the metal on the face of the valve and seat as an engine accumulates miles. Over time, the buildup of heat weakens the metal and pieces will start to break or flake away, forming a hot spot. As the valve begins to leak, compression drops, resulting in a weak or dead cylinder. You will feel a noticeable drop in engine power, smoothness and performance.
- Failing exhaust valve — if an exhaust valve is failing, it significantly increases the exhaust emissions by allowing unburned fuel to leak into the exhaust. An indicator of a possible burned valve is higher hydrocarbon emissions.
- Closed valve — If for some reason an exhaust valve closes up, the lack of clearance (referred to as lash) in the valve train prevents the valve from fully closing, causing it to leak compression and then overheat.
- Conditions that makes the engine run hot or elevates combustion temperatures, including cooling problems, abnormal combustion, loss of exhaust gas recirculation, slow ignition timing, or lean fuel mixtures.
To determine the type of engine repair required to take care of a burned value usually requires the help of a trained auto mechanic conducting a compression test. If a cylinder shows little or no compression, it frequently means the exhaust valve is not sealing. The valve may or may not be actually burnt (melted), but have other physical damage such as cracks or areas where pieces of metal are missing or eroded away from the valve face.
The repair of a burned value, which is considered a major engine repair or rebuild, consists of removing the cylinder head, replacing the bad valve and resurfacing (or replacing) the valve seat. As a rule, the head is usually given a complete valve job at the same time because the rest of the valves and guides probably need attention, too. If one exhaust valve has failed, the rest are probably on the verge of failure if they haven't already started to leak.
Are you concerned about an engine rebuild? The auto professionals at Gary’s Quality Automotive are happy to help with any of your car problems. Contact our ASE-Certified Technicians by calling (308) 381-2295 or go on-line at https://www.garysautoinc.com/ for more information about engine repair. Our auto shop proudly serves vehicle owners in Grand Island, Wood River and Doniphan, NE.
If your car is losing power and the motor isn’t running smoothly, the engine may have “burned values.” If so, this typically requires a major engine repair, or possibly a complete engine rebuild. A “burned valve” is one that has overheated and lost its ability to hold a leak-free seal. Value burning is usually limited to exhaust valves because they run much hotter than intake valves.
There are several reasons why valves burn:
- Normal use--The constant pounding and thermal erosion wears away the metal on the face of the valve and seat as an engine accumulates miles. Over time, the buildup of heat weakens the metal and pieces will start to break or flake away, forming a hot spot. As the valve begins to leak, compression drops, resulting in a weak or dead cylinder. You will feel a noticeable drop in engine power, smoothness and performance.
- Failing exhaust valve — if an exhaust valve is failing, it significantly increases the exhaust emissions by allowing unburned fuel to leak into the exhaust. An indicator of a possible burned valve is higher hydrocarbon emissions.
- Closed valve — If for some reason an exhaust valve closes up, the lack of clearance (referred to as lash) in the valve train prevents the valve from fully closing, causing it to leak compression and then overheat.
- Conditions that makes the engine run hot or elevates combustion temperatures, including cooling problems, abnormal combustion, loss of exhaust gas recirculation, slow ignition timing, or lean fuel mixtures.
To determine the type of engine repair required to take care of a burned value usually requires the help of a trained auto mechanic conducting a compression test. If a cylinder shows little or no compression, it frequently means the exhaust valve is not sealing. The valve may or may not be actually burnt (melted), but have other physical damage such as cracks or areas where pieces of metal are missing or eroded away from the valve face.
The repair of a burned value, which is considered a major engine repair or rebuild, consists of removing the cylinder head, replacing the bad valve and resurfacing (or replacing) the valve seat. As a rule, the head is usually given a complete valve job at the same time because the rest of the valves and guides probably need attention, too. If one exhaust valve has failed, the rest are probably on the verge of failure if they haven't already started to leak.
Are you concerned about an engine rebuild? The auto professionals at Gary’s Quality Automotive are happy to help with any of your car problems. Contact our ASE-Certified Technicians by calling (308) 381-2295 or go on-line at https://www.garysautoinc.com/ for more information about engine repair. Our auto shop proudly serves vehicle owners in Grand Island, Wood River and Doniphan, NE.
