In any combustion engine, lubrication is essential to reducing wear, minimising friction, and extending engine life. But what if your oil is telling you that wear is already happening?
One of the most telling early warning signs is elevated iron levels in your engine oil. If your oil analysis flags high iron, it’s not just a mild warning—it means internal wear is already underway.
What Does Elevated Iron in Oil Actually Mean?
Iron shows up in oil samples when metal engine components begin to wear. The source is often:
- Cylinder liners
- Crankshaft and camshaft journals
- Valve train components
- Gears and timing chains
Under normal operation, a protective oil film prevents direct contact between moving metal parts. But when that film is compromised — due to degraded oil, overheating, fuel dilution, or contamination — surfaces can begin to grind against each other, generating microscopic iron particles.
These particles become suspended in the oil and are picked up during routine analysis.
What’s an Acceptable Level of Iron?
Oil analysis labs typically measure wear metals in parts per million (ppm). For iron, here’s a general guide for diesel engine oil samples:
| Normal Iron (ppm) | Caution | Critical |
|---|---|---|
| 0–25 ppm | 26–40 ppm | >40 ppm |
Common Causes of High Iron
Several issues can cause elevated iron in engine oil:
Extended oil intervals — running oil past its useful life allows acids and soot to accumulate
Inadequate lubrication — wrong viscosity grade, oil breakdown, or low pressure
Fuel dilution — thins oil and reduces its film strength
Coolant ingress — introduces corrosive elements and water into the system
Abrasive contamination — dust or dirt ingress due to poor air filtration
Abrasive contamination — dust or dirt ingress due to poor air filtration
How Oil Analysis Helps You Stay Ahead
Regular oil analysis gives you visibility into internal wear without tearing down the engine. A standard analysis will check:
- Wear metals: iron, chromium, lead, copper, aluminium
- Contamination: fuel, soot, coolant, water, silicon (dirt)
- Oil condition: viscosity, oxidation, nitration, TBN (base reserve)
By trending iron levels across multiple samples, you can spot abnormal wear early and take proactive steps:
- Shorten oil change intervals
- Investigate filtration issues or coolant leaks
- Plan repairs or component replacements before failure occurs
For example, if your previous sample had 40 ppm iron after 150 hours, and your next sample shows 100+ ppm at the same interval, that’s a red flag that shouldn’t be ignored.
Want to Know if Iron’s Building Up in Your Engines?
Oil analysis typically costs less than £30 per sample, yet it can help you avoid thousands in engine repairs or the total loss of a power unit. It’s a low-cost, high-impact tool for fleet managers, plant operators, and anyone running diesel assets.
Our oil analysis service is fast, simple, and designed for operators who want peace of mind. Whether you’re running trucks, generators, or off-road machinery, we can help you spot iron wear before it becomes a breakdown.
Get in touch today to book your sample kit or request a consultation.