ATV Smoking After Oil Change (Easy Fix!)


Holy S**t this looks serious, no need to panic, blue smoke after an oil change is common and usually the fix is simple.

The most common reasons ATV’s smoke after an oil change is oil spilled on hot components and too much oil.

In this post you’ll learn why an ATV smokes after an oil change and what you can do to fix it, right now.

ATV smoke after an oil change usually fixes itself. Accidentally spilling some oil close to the exhaust will cause smoke as the exhaust heats up. When the heat burns off spilled oil, the smoke will stop and problem solved. Similarly, jacking up your ATV to change the oil may cause oil to enter the cylinder, this too is a self fixing issue and should burn off quickly.

If however the smoke doesn’t clear after ten minutes, shut down the machine and begin your investigation by checking oil level.

ATV Oil Change

Changing the oil is as you already know super important. The oil helps cool as well as lubricate the internal components. The filter collects all the micro filings caused by natural engine wear and tear.

The filings, if allowed to roam freely inside the engine would act like an abrasive prematurely wearing out internal engine components like crankshaft & camshaft bearings.

Oil Level

Oil quality is extremely important, but so to is quantity. Everyone knows too little oil in a motor spells trouble, but what about too much?

Excessive oil could damage your engine, but no oil definitely will. So, while too much oil is bad for your motor, it’s rarely terminal.

The moving parts inside the engine need room to move, the piston, crank shaft and other components create pressure inside the engine as they move. (Known as crankcase pressure)

A crankcase is only partially filled with oil for this reason. The void allows room for positive and negative pressure.

When this void is filled with oil, it causes excessive crank pressure and oil is forced to move into places it shouldn’t.

What Causes The Smoke

Too much oil in an ATV engine has to go somewhere, the oil has no choice. The forces of the crank pressure are too great. The excessive oil often causes crankcase gaskets to fail and leak oil onto ground.

Oil may also be sucked up into the carburettor via the breather assembly, and ingested by the engine which causes dramatic looking blue smoke.

Oil can make it’s way past the piston rings and into the combustion chamber, this too results in blue smoke. In addition excessive oil inside the chamber may be expelled into the hot exhaust system, causing even more blue smoke.

Fix The Smoking

This is usually an easy problem to solve. Allow the engine to cool and parked on level ground check the oil level carefully. Expect to see a reading that’s way over the full mark.

Some dipsticks need to threaded all the way home until they seat to get a correct reading and some don’t. Check your models procedure.

If it’s a case of too much, you can simply remove the excess oil using a siphon or drop some out the bung. If you choose to drain the oil, don’t be tempted to keep it for top ups. Crap from the underside can fall in to the oil catch, contaminating the oil.

Oil Level Isn’t Too Full

If you’ve checked your oil level and it’s perfect. A couple of other likely problems to check including :

Cylinder head gasket failure – Depending on your style engine and where the gasket fails. A failed head gasket can cause oil to enter the combustion chamber, and that means smoke. The only fix here is to replace the gasket.

Whats a head gasket? It’s a heat resistant graphite gasket that’s sandwiched between the cylinder head and the cylinder. Its function is to seal the combustion chamber. Head gasket just wear out and gaskets are a pretty common failure.

But why would it fail after an oil change? Yea, it’s a fair question. I have had this happen twice in my wrenching career and my thoughts are along these lines.

I believe fresh oil an already weak gasket and blow by are to blame.

Whats blow by? Compression that escapes past the piston rings is blow by. It happens naturally as an engine ages. Unscrewing the dipstick and watching it’s movement as an engine idles is very loose gauge of how much blow by a motor has.

Fresh oil is heavier and does a better job sealing leaking compression past the rings. Reduced blow by ordinarily would be a good thing. However the now increased combustion chamber compression blows out an already weak spot in the head gasket.

The now damaged gasket allows oil into the cylinder as the piston moves down the bore. Oil in cylinder equals smoke.

Oil Type

Does oil type make any difference? Yes, the oil spec by your model can make a difference. If your machine requires mineral oil and you use a lighter semi or fully synthetic, you may notice smoke.

This isn’t necessarily a problem with your engine, the tolerances of your piston rings may just not be compatible with the much lighter oil type.

John Cunningham

John Cunningham is an certified mechanic and writer on ATVFixed.com. I’ve been a mechanic for over twenty years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of ATV ownership, from maintenance, repair to troubleshooting.

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