Car Start But Blue Smoke Comes Out from Exhaust

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Car Start But Blue Smoke Comes Out from Exhaust

If the car start but blue smoke comes out from Exhaust, it means that the engine is burning oil. The problem is why the engine is burning oil, that is what we are going to find out. When an engine burns oil, the most common reason is a bad ring. If the engine has a bad ring aside from burning oil it will also show signs of loss in power, especially when driving uphill.


Blue Smoke Comes Out from Exhaust


The possible reason why car start but blue smoke comes out from an exhaust

(1) Bad rings
(2) Bad stem seals
(3) Leaking turbo charger seal

Bad rings
If the engine has a loss in power especially when going uphill. And in addition to blue smoke after starting, the engine seems to be less powerful than it used to be.

Blue Smoke Comes Out from Exhaust

The combination of blue smoke coming from the exhaust along with a loss of engine power is a telltale sign of the rings being bad. The purpose of the rings is to keep the engine oil from entering the engine combustion chambers and also, the rings maintain proper engine compression for adequate power. Why does an engine need compression? Engine need compression so that it can generate power.

Now, when the rings are bad or for example worn out, the ring will become sloppy and will not adequately seal the wall in between the piston and cylinder. In this case, it causes the oil to leak out into the combustion chamber and burn - hence, creating blue smoke coming out the exhaust. Also, it causes weak compression which means weak engine power. As the rings get worse, the more blue smoke and weaker the engine is.

What to do?

You'll need either a ring job or a new engine. Expect that this is going to be serious money.  Does your car still under warranty? If yes, you're covered.  If no, first take the car to a car shop that specializes in this kind of job and have the mechanic positively verify that the rings are indeed bad.  This can be done with a "wet compression test".  The test involves removing one of the spark plugs, screwing a compression gauge into the spark plug hole and taking a compression reading while the engine is cranking.  Then, the compression gauge is unscrewed and some oil is squirted into the cylinder.


The compression gauge is then screwed back in and another compression reading is taken again while the engine is cranking.  If the second reading is significantly higher than the first, the rings are indeed bad.  After considering the cost of a ring job/new engine, you may want to consider replacing your car.

Bad stem seals

If the blue smoke is notice mainly when accelerating usually the problem is a bad stem seal. Some oil is leaking past the valve stems and into the combustion chamber. This oil then burns and comes out of the exhaust as blue smoke.

What to do?

You will need to have the valve stem seals replaced.  If this vehicle is still under warranty, this procedure will be covered. If it's not, Expect that this is going to be serious money

Leaking turbocharger seal

If your car has a turbocharger, turbocharger seals leaking is possible. Occasionally, the seals of a turbocharger leak causing the oil to reach the exhaust system of your car.  The oil "smokes" when it comes in contact with hot exhaust components and then, of course, out it, comes ... blue smoke.

What to do?

Take your car to a car repair shop and have the mechanic verify that the turbocharger seals are indeed leaking.  If this is the case, have the problem fixed.  If this vehicle is still under warranty, this service will be covered.

Related Topics:

Black Smoke from Exhaust of Car

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