Losing Oil But Don’t See a Leak?
Losing oil without a trace is one of the most frustrating problems a vehicle owner can face. You’ve checked the ground expecting to find a puddle, but there’s nothing there. It’s as if the oil vanished into thin air!
So where did the oil go? What follows is a comprehensive guide to oil consumption, which details everything you might need to know when your vehicle is losing oil, with no identifiable leaks.
Is Some Oil Loss Normal?
At some point in every vehicle’s service life, oil consumption will occur. This is especially true of high mileage vehicles that have logged a significant amount of wear and tear.
However, in most cases, this oil consumption is nominal, meaning that it should be so minor that it should go largely unnoticed.
The difference, and overall point of concern, comes when oil loss or consumption becomes significant enough that you must top off your engine oil in between changes.
Causes of Oil Loss When There’s No Visible Leak
As we have discussed above, oil loss without any sign of an external oil leak points strongly to oil consumption. This term describes the burning of oil during the combustion process or the mixing of oil with other automotive fluids. Here are several of the most common causes of oil loss, without visual indication of a leak.
1) Worn Valve Seals/Guides
Valve seals prevent oil from an engine’s cylinder from entering a combustion chamber, during valve actuation. As these seals degrade, oil consumption is sure to follow.
How to Fix:
The unfortunate part of identifying worn valve seats is that their replacement is no laughing matter, and is somewhat invasive to perform. Nonetheless, the only proper way to repair this type of issue is to replace the offending valve seals.
2) Worn Piston Rings
Another common cause of oil consumption is worn piston rings. These rings ride between the outer diameter of each piston, and the inner diameter of each cylinder.
How to Fix:
The only way to address worn piston rings is to tear the compromised engine down for overhaul. This is major work and is almost always expensive to conduct.
3) Compromised Gaskets
There are several gaskets within the modern internal combustion engine that, when compromised, can lead to oil consumption. Two of the most prevalent of these are the head gasket and intake gasket.
How to Fix:
To resolve this issue, replacing the faulty gasket itself is the only solution. A certain degree of diagnostic work will also be required to determine which gasket, exactly, was the one that failed.
4) PCV System Failure
It’s also possible for a failure in a vehicle’s Positive Crankcase Ventilation system to cause issues related to oil consumption. A stuck PCV valve can lead to crankcase overpressure. This effectively pushes oil laden crankcase gasses past an engine’s piston rings.
How to Fix:
The first step to fixing this issue involves verifying the presence of a PCV System issue. This can be done in one of several different ways, though most all center around checking for flow in a single direction only. Once an issue has been identified, repair of the PCV System can begin. This often involves replacing the PCV valve itself.
