Why Is Oil Coming Out Of Exhaust? [Solved]

Are you too confused as to why oil is coming out of the exhaust instead of tailpipe smoke? Well, it could be an indication of something not ticking right within the guts of your engine. Oil coming out of exhaust pipe can be early indicators of some serious impending failures in the engine’s internal components, such as piston rings, valve guides, bad head gasket, and so on. 

Through this article, you will learn simply why the oil starts to come out of the tailpipe and what you can do to prevent it and fix it. 

Causes For Oil Coming Out Of Exhaust And Solutions

Oil coming out of your exhaust pipe is definitely an unusual occurrence. Oil leaks are not easy to stop flow wise and they can find their way into the combustion chamber. Here are the common causes and their solutions- 

1. Problem With PCV System

The gases coming out of the engine chamber pass through the PCV. The oil coming out of exhaust valve then gets to the combustion chambers for reignition. Sometimes, the increasing amount of volume of the gas can create excessive pressure in the engine, in the case where there is an obstruction. This will then force the oil to flow directly into the exhaust pipe.

Solution For Stuck PCV

If you find blue smoke along with oil-fouled spark plugs, it is a typical indicator for this kind of problem. To get it fixed, get the PCV valve replaced. Replacing the PCV valve will be a piece of cake if you follow the service manual. Either way, you can also try to clean the PCV valve with brake or carburetor cleaning spray, in 80% of cases, it will fix in this way. 

2. Valve Guides That Are Worn

The gas fluxes into and out of the engine. It is mainly controlled by the valve guides. These valves contain seals, that can wear out over time, especially around their shafts. The motor oil will then spill and flow directly into the exhaust gases.

And once this happens, you will observe blue smoke coming from the exhaust. You will also observe poor engine performance when cold when this problem arises.

How To Replace Worn Out Valve Guides?

For worn valve guides, there are a number of repair options that are available. Replacing the guides and knurling with aluminum heads and certain cast iron heads is the most common method. When the valve leads are a different kind of metal than the valve stem, they perform best.

3. Clogged Out Exhaust

Carbon buildup in the engine can be seen through soot, which will eventually coat the inside of your exhaust muffler in no time. There are many factors that can contribute to the carbon buildup inside the engines. This includes bad driving habits and also poor gas.

Carbon buildup is very common in the 2-stroke engines, they use oil as a lubricant, that is directly added to the fuel mix. The carbon deposits are really thick, and they can affect the engine’s performance. 

How To Remove Carbon Deposite

The removal process of carbon deposit from your muffler is a very easy process. This will not only solve the oil build-up problem but will also restore the gas flow and improving engine performance. You can spray the carbon cleaner inside the muffler tip or scrub the inside of the tailpipe with a hard brush, in order to remove the carbon deposit.

4. Turbo Oil Leaks

When there is a kink or a partial block in the oil feed line of the turbo, it will cause the oil pressure in the bearing to increases, hence causing leaks from the ends of the turbo. It has the same effect as that of piston ring blow-by or crankcase blowby. It can also be due to the worn-out oil seals inside the turbo, this can happen due to poor turbo maintenance or the simple age of the turbo.

Option For Turbo Rebild

You can achieve this through a turbo rebuild kit that is easily available in the market. Get the bearings replaced along with the new bolt on the compressor Wheel. Turbochargers can be an expensive affair so it is better to get them to rebuild. You can’t reconstruct a turbo personally.

The shafts must be calibrated and the seals substituted. It might not even be well enough if you not have enough knowledge.

5. Engine Gone Bad

A worn-out engine will cause oil to come out car exhaust. The lubrication from the oil of the engine passes through the spring seals, and when the valve guides are worn, it can cause this problem. Worn-out piston rings can also allow the seepage of the oil into the combustion chamber and it will throw oil through the exhaust. 

Can You Get Engine Rebuild?

In general, reconstruction of an engine might be a significant undertaking, but with the correct research, planning, and preparation it is feasible to do so and will be very economical instead of getting a new one. However, in some cases, you can find a used engine replacement for much cheaper.

In that case, you should replace it. Make sure you undertake the exercise with quality parts and a skilled mechanic. 

How Serious Is Tailpipe Oil Leakage?

Oil coming out of exhaust can be very dangerous especially in the diesel engine. It can cause the diesel engine to run away. It can result in an over the speed of the engine, also due to the uncontrolled acceleration, it can cause a serious road accident. An engine runaway is a very serious situation and must be avoided by doing timely repairs. 

How Much Will It Cost To Stop Internal Oil Leaks?

The cost involved is according to the job being done. Depending on the vehicle make and model, the costs of changing your valve guiding scale will vary. The good news is that the cost of valve guiding seals ranges on average from $30 to $100. If critical components have been damaged, Turbo reconstruction prices can vary dramatically.

Reconstructions start at $400 for regular journal turbos, and $550 for ball turbos, but note that if critical components have been damaged the price will rise.


Oil coming out of exhaust is a serious sign of a worn-out engine and you should not delay the fix as ultimately, it can either destroy your engine or cause you to be in a serious situation like an engine runaway. If you still have any questions, then comment down below. 

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