Is a Subaru piston slap normal?
As a seasoned auto service provider, I often encounter questions about various engine noises, and one common concern among Subaru owners is the phenomenon known as piston slap. This article aims to clarify what piston slap is, whether it is normal in Subaru vehicles, and what steps you can take if you experience this issue.
Understanding Piston Slap
Piston slap occurs when the piston in an engine moves slightly within its cylinder, causing a knocking or slapping sound. This can happen due to several factors, including the design of the engine, wear and tear, or the tolerances between the piston and cylinder walls. In many cases, piston slap is more noticeable when the engine is cold and may diminish as the engine warms up.
Is Piston Slap Normal in Subarus?
For Subaru vehicles, particularly those equipped with the EJ series engines, some degree of piston slap can be considered normal. This is primarily due to the engine's design, which includes a unique horizontal opposed (boxer) configuration. Here are some key points to consider:
- Engine Design: The boxer engine design allows for a lower center of gravity and improved handling, but it can also lead to more noticeable piston slap.
- Cold Starts: Many Subaru owners report hearing piston slap during cold starts, which often lessens as the engine reaches operating temperature.
- Manufacturing Tolerances: Subaru engines are built with specific tolerances that may allow for some piston movement, contributing to the sound.
When to Be Concerned
While some piston slap can be normal, there are situations where it may indicate a more serious issue. Here are signs that you should consult a professional:
- Persistent Noise: If the knocking sound continues even after the engine has warmed up, it may be a sign of excessive wear.
- Loss of Power: If you notice a decrease in engine performance or power, it could be related to piston slap or other engine issues.
- Oil Consumption: Increased oil consumption or the presence of oil leaks may indicate problems that need to be addressed.
Conclusion
In summary, while some piston slap can be normal in Subaru vehicles, especially during cold starts, it is essential to monitor the situation. If you experience persistent noise or other performance issues, it is advisable to seek professional assistance. At Kevin's Autos, we are here to help you diagnose and resolve any concerns with your vehicle, ensuring it runs smoothly and efficiently.
Frequently Asked Questions
Should I be worried about piston slap?
The noise that piston slap produces usually clears up as the engine heats up. The piston expand and fit in the bores more snugly. The results of piston slap usually lead to increased wear of the piston, cylinder wall, increased oil consumption,, and eventually Catastrophic engine failure.
What is the biggest problem with Subaru engines?
Oil consumption
Some Subaru engines have been known to consume excessive amounts of oil. This can be caused by a number of factors, including worn piston rings, a leaky valve cover gasket, or a failing oil pump. Symptoms of oil consumption include: Low oil level.
Will thicker oil stop piston slap?
Generally, it will be worst when the engine is cold, and quieten down as it warms up. A thicker oil may help slightly, but creates other issues so is not really a great idea. Going from a 10W30 to a 10W40 would be OK, but probably won't do enough to matter. Over time as the wear gets greater, the noise will get worse.
Can you get rid of piston slap?
The only way to fix it is to tear the engine apart and replace the piston rings. 99% of the time, the costs of repairing the engine exceeds the market value of the car. Just either replace the engine or buy another car.
Can I ignore piston slap?
So in answer to your question... If piston slap is just ignored and left to slap away it can be very harmful to an engine, and yes it can be prevented/avoided. Or at the very least minimised.
Is piston slap worth fixing?
As we've discussed before, piston slap is usually a minor issue, but a very annoying one in terms of sound. Very rarely is it worth digging into the block to address the problem without doing a full rebuild.
What year does Subaru have a bad engine?
The performance-oriented Subaru WRX and WRX STI from 2008 to 2014 unfortunately did not escape their own set of difficulties. These cars were plagued with engine problems. Such problems included bearing failure in the EJ series of engines, leading to a major engine rebuild or replacement.
Is it safe to drive a car with a piston slap?
I almost always recommend driving it until other problems surface. Heavier oil might be better for quelling piston slap, but you run the risk of not getting oil where it needs to be in a timely fashion. If you aren't running a full synthetic oil, this would be the only change I'd make.
Can you still drive with a piston slap?
I almost always recommend driving it until other problems surface. Heavier oil might be better for quelling piston slap, but you run the risk of not getting oil where it needs to be in a timely fashion. If you aren't running a full synthetic oil, this would be the only change I'd make.
What is the number one problem with subarus?
Transmission issues are the most common problem in Subarus, but defective airbags, faulty fuel pumps, weak windshields, and electrical issues are also known to happen. Subarus generally receive high reliability ratings, according to RepairPal. Transmission issues are the most common problem in Subarus.
