The causes of excavator releasing blue colored smoke is likely due to the combustion of engine oil

Blue smoke is one of the more deadly issue for an excavator. The blue colored smoke is the result of engine oil being burned and engine oil is not supposed to be ignited. 

If your engine oil gets burned, the smoke should look something like the image below:

Co-existing symptoms when blue smoke is noticed

Normally the amount of blue smoke emitted are consistent with the engine oil level. The higher the level of engine oil in the tank, more blue smoke gets emitted as the result of combustion. You will also notice abnormally high level of engine oil consumption.

Potential causes of blue smoke in your excavator

1. Damaged piston, piston ring - See if the piston is functioning as intended. It's possible that the piston ring gets stuck or is just broken. This is also the likely cause if you find oil dripping from the engine
2. Loose spacing between gasket and piston
3. Loose valve piping in the engine - Disjointed valve system, basically look for loosing valves or pipes at anywhere the engine oil might go. Look for poorly connected valves and bad seals
4. Turbocharger - Try taking down the turbocharger and see if there is any engine oil in the valves
5. Overfilled engine oil - This is mostly a human error
6. Engine oil tank filled by other substances - If you didn't fill the tank but the engine oil still gets overfilled, then it may be due to other liquid entering the engine oil tank. This can potentially be a very serious issue
7. Engine oil viscosity too low

Common solutions 

1. Check engine oil level
2. Check turbocharger, see inhale pipes and exhale pipes, normally it should be dry inside. If there's liquid then it's likely engine oil and engine oil will make it's way to exhaust gas valve
3. When starting excavator, see if there's any black or dark smoke, if yes, then it's likely the turbocharger
4. Normally problematic turbocharger does not cause major engine oil loss, it could be the exhaust valve
5. You should use the correct engine oil with appropriate viscosity level, change viscosity according to season. Diesel engine should use diesel engine oil
6. Check exhaust pipe gas exhalation level, if there's excess level of gas exhalation and oil drips, then maybe it's time to send it to repairs

Disclaimer: Original post and images by cehome.com. This post is a translated work from cehome and other construction machinery documents available in our company. Please do point out if there's any error or mistranslation.