Attentive drivers are always aware when something seems off with their vehicle. Some observations are benign while others hint at larger problems. An example of the latter is finding shiny metal particles inside your oil.
Keep reading to find out more about the cause for the sudden emergence of fine metal shavings and metal flakes in a vehicle’s oil, and what to do if you ever find yourself in that position.
Is It Normal to Have Metal Shavings in Oil?
The engine oil in most vehicles will have small, microscopic metal particles in it. Small enough that it is not noticeable to the naked eye.
Unless, of course, they stick to a magnetic drain plug or something similar. And even then, it should be unlikely they would be noticeable in size.
To have a sudden accumulation of metallic particles in an engine’s lubricating oil is “not normal.” To the contrary, it is indicative of something bad happening to an internal component or a rotating assembly of the engine.
There may be an exception to this rule at times, if the threads of an oil drain bolt were stripped during the course of an oil change.
There still may be a tiny amount of metal shavings in your oil drain pan if you removed the drain plug, replaced the drain plug, and may even have rethreaded the strips from the oil pan hole.
What Does Metal Shavings in Oil Mean?
Generally, a large buildup of metal shavings in an engine suggests there is rapid wear of the bearings or other moving surfaces.
When wear occurs from these parts of the engine, metal comes off these parts and enters the oil loop from the area damaged and stays in the oil until it is safely disposed of during oil change service.
After at least one of the engine’s bearings has worn to the extent of metal shavings in the oil, the engine has already sustained damage that is actually irreversible.
This is often just the beginning of a wear pattern that will often continue and eventually propagate over time through the engine. More often than not, there will be visible metal shavings with all oil change services.
How Serious is This Issue?
Accelerated bearing wear is a problem because it is a vicious cycle. The main, rod, and camshaft bearings within an engine wear, increasing tolerances beyond the manufacturer’s specifications.
The tolerance, in terms of bearing clearance, is essential to engine operation and relates back to the engine’s ability to hold oil pressure.
After repeated use, those worn bearings do not hold pressure in the same manner as they once did when those bearings were new, so they allow oil to pass without any resistance. Upon failing to build or maintain oil pressure, we witness a decline in oil pressure.
Reduced oil pressure, and as such, bearings have been deprived of important lubrication. This complicates this situation considerably and can trigger multi-bearing failure without undue delay, often ending up with spun bearings, which require substantial repairs.
In addition, severe oil pump failure will present itself as a ‘knocking’ or a ‘ticking’ noise, while the engine is running—this is typically a sign of failing bearings (later stage) and oil starvation at the upper end of the engine when running.
Will an Oil Filter Catch Metal Shavings?
While any oil filter can capture a percentage of metal debris and contaminants in an engine’s oil, it is not 100% reliable. Generally, oil filters can capture the vast majority of larger metal shavings and contaminants when circulating in an engine.
However, a lot of metal particles are too small for an oil filter to capture as well. When these organic particles are in a sub-microscopic state, they can keep circulating and eventually pass through an engine’s bearings and act as an abrasive of sorts.
Over time, this tedious grinding can increase the wear and tear of bearings and the engine, especially if oil is not changed at factory-recommended service intervals.
If an engine is questioned about its condition, a used oil filter can provide some informational value. As such, many skilled mechanics will cut and reveal the inner paper element of an oil filter.
The inner element can then be evaluated for metal fragments and shavings, and can provide clues about the bearings, wear surfaces, and overall health or condition of an engine.
What To Do When You Find Metal Shavings In Engine Oil?
Finding metal shavings in engine oil is certainly alarming and should be investigated.
Investigation will involve the removal of the oil pan and the bearing caps (for inspection) along the bearing surfaces for reasonable wear. If significant scarring or wear is present, you are dealing with bigger issues.
Unfortunately, options are limited if you have experience with rapidly deteriorating bearings in the rotating assembly of your engine.
In most cases, you will need to remove the engine and perform an overhaul. This can be a very costly repair if this is what you choose to do, as the cost for engine repair very often exceeds the total value of many older, high-mileage vehicles.
Alternatively, you may consider a replacement engine from a junkyard. This will undoubtedly be a far cheaper option than engine overhaul costs.
If you are competent at removing and replacing an engine, it will be an economically viable option, because you will save all of the labour costs, saving hundreds.
What About Metal Shavings in Your Transmission Fluid?
In contrast to a vehicle’s engine oil, it’s reasonable to find some amount of metal shavings in your transmission’s fluid. This is especially true if a vehicle has been driven for some time without service to change the fluid/oil.
Most of the metal shavings you can see are typically a normal byproduct of internal gear mesh and will only indicate normal wear. In fact, many transmission pans have magnets to collect this kind of debris.
However, keep an eye out for the occasional metal shavings, typically large enough to be pinched between your fingers, or having sharp edges.
These types of metal shavings are likely to represent developing problems and represent abnormal wear. Any vehicle in this situation should be evaluated by a transmission repair facility.