Oil analysis
The final test is the expensive one and the one I started with – oil analysis. Like a blood test, an oil analysis will tell you what you can’t see. Not only does it look at wear of various parts of the engine, it will also tell you the state of the oil and if water or fuel is leaking into the engine. .
Read more: https://www.pbo.co.uk/all-latest-posts/engine-health-check-diesel-68318