6 SYMPTOMS OF BAD VALVE STEM SEALS
Do you go to start your car in the morning and notice blue smoke coming out of the tailpipe? This could be caused by defective valve stem seals. Their main purpose is to prevent the engine oil from leaking into the combustion chamber. So, as you can imagine, when the valve stem seals start to go bad, it can negatively impact your engine, so look out for the symptoms that we’ll discuss today.
symptoms
blue smoke
The first symptom of bad valve stem seals is blue smoke coming out of the exhaust. You’ll typically notice this when you go to start your car after it’s been turned off for a while. To paint a better picture in your head, let’s consider the engine’s operation cycle. When it’s on, the oil pump circulates oil throughout the engine. However, once you turn the engine off, any remaining oil that’s at the top will sink into the combustion chamber through the defective valve stem seals. So when you go to start your car, the oil that’s been collecting overnight will burn with the air-fuel mixture, resulting in the blue smoke coming out of the exhaust.
loss of oil
The second symptom is a loss of oil. You'll notice that you need to add oil more frequently. This happens because the oil escapes into the combustion chamber where it gets burned off in the process.
bad smells
The third symptom is noticing bad smells. When the oil is burning, it can produce an unpleasant smell. This smell can be best described as a combination of oil and exhaust fumes.
oil traces
The next symptom is oil traces in the tailpipe. You can grab a white napkin, and wipe the tailpipe to see if it will pick up any oil. If there’s any, the valve stem seals could be the cause for this.
poor engine performance
The fifth symptom is overall poor engine performance. Oil that’s leaking into the combustion chamber can eventually foul the spark plugs. This can affect the engine's performance and cause misfires.
engine light
The last symptom is an engine light. Since your car could experience misfires, any of these misfire-related codes may pop up:
P0300
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308
P0309
P0310
P0311
P0312
If your car is made after 1996 You can use an OBD2 scanner to retrieve these codes.
It’s important to note, that if you continue driving with this issue, the burnt oil could eventually harm the catalytic converter and oxygen sensors, leading to more problems in your vehicle.
If you concluded that your valve stem seals needs to be replaced and you want to do it yourself, I would recommend getting a repair manual here. You can use code “AD10VA” for 15% off one-year subscriptions for any US Order.
Check out my YouTube video!
Disclaimer: Some links in this article may be affiliate links.
