Why does my car burn oil?

In this series of Q&A posts we are using google’s autocomplete function to find the most commonly asked questions about cars and giving them each a definitive answer. This week we answer the question “why does my car burn oil?”

As vehicles age, there are a number of reasons why it might start to burn oil. This is something you will definitely notice, even if you don’t feel like you are that in tune with your vehicle’s quirks. That is because you will see blue smoke coming from your tailpipe accompanied by the unmistakable smell of, well, oil! If you have ever smelt from an open quart of motor oil or machine oil you will recognize it immediately.

Let’s quickly outline the symptoms and possible causes then take a look at when it needs urgent repair.

Symptoms

You will see blue smoke coming from your tail pipe accompanied by the smell of burning oil, indicating excessive oil consumption.

Causes

A number of things can cause this excess consumption in different ways but with the same result. That is, engine oil entering the combustion chamber and burning off. Some of the main causes include:

• Damaged or worn valve guides
• Damaged or worn valve seals
• Collapsed, broken or stuck piston rings
• Damage pistons
• Damage piston walls
• Clogged breather valve
• Oil leaking from seals and gaskets

The Repair

Generally speaking, any repair that involves engine disassembly is very labour intensive and thus quite expensive. That does not mean that you need to immediately outlay for a major repair. You first need to decide if it is important for you to reduce your oil consumption or can you live with adding a litre of extra a month (which would be A LOT) at a cost of about $30 a year, when the vehicle otherwise runs perfectly fine. Some cars are notorious for consuming more oil than others and it might be something you have to live with. A vehicle that is over consuming oil can last for many years without incident, BUT you need to monitor the oil constantly and not let it run dry to avoid engine seizure (which brings with it the most expensive repair of all).

Gerry Brouwer – Parkside Motors