Blue Smoke – How to Troubleshoot an Engine Burning Oil
It’s normal to see a car’s exhaust when it’s first cranked up in the morning. Drivers will also see the exhaust if it’s particularly cold outside. However, what they’re seeing is mostly water vapor (it’s white). They’re not really seeing smoke. That changes if you can see your customer’s exhaust on warm days or after the engine has warmed up to its normal operating temperature. If the exhaust looks bluish and smoky, rather than being mostly water vapor, what you’re seeing is a sign that there is an engine burning oil situation, which is a bad thing.
Making a Diagnosis
Car engines can burn oil for any number of different reasons. However, none of them are good, especially in cheap engines newly purchased. At best, it’s a sign that there’s wear and tear, and that the engine oil level will drop significantly between oil changes, which can cause serious damage if your customer isn’t paying attention. Making the right diagnosis here is important.
The first place to start is with the EGR valve. As you should know, the EGR system is the primary culprit for a number of problems, including spark knock. However, it’s an important part of the vehicle’s emissions system, and needs to be checked for operation. If the problem isn’t here, though, you’ll need to dig deeper.
The car engine’s rings and seals are the most likely culprits if the EGR valve is working normally. You’ll see this particularly with older model engines. To confirm that this is the problem, you’ll have to test the engine’s compression. Low compression indicates that the rings and seals are worn out and not working properly.
When you inform your customer that they need to replace both rings and seals, be prepared for resistance. Most customers know that an engine can be run for quite some time while burning oil without replacing rings or seals. The real danger here is that they’ll run it too long without adding oil and lock it up. It’s best to convenience them that they need a ring job, or you can start pricing replacement engines if they would prefer (or if the problem is severe).
If the problem is serious and there’s been substantial damage to the engine over time, it might be best just to recommend a replacement engine (rebuilt, remanufactured or used engines can all work). Make sure to quote both the price and the time it will take to complete the replacement.
