There are a few reasons an ATV may smell like it’s burning oil. Some of them are nothing to worry about, but if your quad is actually burning oil, that is a cause for concern. Lets go over a few things to check to see if you really have an issue to deal with or not.
The most common cause of an ATV oil burning smell is a worn out piston ring or damaged cylinder wall. This causes oil to enter the combustion chamber and burn along with the fuel air mixture giving you a distinct burnt oil smell. Perform a leak down test to see how well your engine is containing pressure, this will tell you if you have worn piston rings or a damaged cylinder wall.
How To Tell If An ATV/UTV Is Burning Oil
Well first off, you will be able to smell the oil burning coming from the engine or the exhaust. Another way to tell is if you start seeing blueish white smoke coming from the exhaust when the engine is running.
Keep an eye on your oil levels, if you notice the oil level dropping after only a few rides, you’re probably burning oil. Some quads will burn the oil slower and it will be harder to tell by just checking the oil levels.
Most Common Reasons An ATV Burns Oil
We already talked about the most common reason being damaged or worn piston rings or cylinder wall. I will go over how to perform a leak down test to be sure later on. First lets go over some other common reasons that will be cheaper and easier to diagnose.
ATV Is Brand New
If your ATV is brand new it may have starter oil still in the engine. This oil is put in the machine from the factory and helps keep the parts protected during shipping and storage. A burning smell is normal at first if your ATV is brand new.
Do not forget to change the oil before you put your first 10 hours or 100 miles on the ATV. When you do this first oil change also check the valves for adjustments while your at it. This will be the most important oil change of the ATVs life, please do not forget to do it.
In fact, some manufacturers will void the warranty if you do not change the oil and do a 100 mile valve inspection. Keep that in mind and take good care of your engine.
Wrong Type Of Oil
A lot of times people end up putting the wrong type of oil in their ATV engine. Doing this might not necessarily cause the engine to burn oil, but could easily give off a weird smell that will make you think it is. And certain types will oil will actually overheat and burn inside your engine will you’re riding it.
It’s always best to stick with the manufacturers recommendation, but here’s an example of the type of oil you’re looking for a 4 stroke ATV engine. Valvoline SAE 10W-40 ATV/UTV Engine Oil from Amazon is a good example of the type of oil you should be running in your quad.
You want a good oil that will protect a wet clutch and prevent deposit formations. Just throwing any old oil in your engine will lead to problems eventually. Get the right type of oil and put the right amount in your engine.
Wrong Amount Of Oil
A lot of people over-look the the simple things to keeping an ATV is good driving condition. One of the most common is over or under filling the engine oil. With too much oil in the engine, you may notice oil starting to leak out of the exhaust or being burnt up in the engine.
Having not enough oil could also cause an oil burning smell coming from the ATV. This is because there’s not enough oil to keep the engine parts from creating heat through friction. This extra heat will burn the little oil you have left in the engine. Always check your oil levels and keep your oil level in between the marks found on the oil dipstick.
To properly use an oil dipstick, you want to remove the dipstick completely and clean it off with a paper towel. Then reinsert the dipstick without screwing it down or tightening it. Pull the dipstick back out and make sure the dipstick is covered in oil up to the full marking on the dipstick, not past it. Add oil or drain oil from the oil drain plug if necessary.
Oil Getting Into Muffler
You may simply have oil in the muffler that is being burnt off by the heat from the exhaust. This can build up over time and will need to be purged from the muffler to get rid of it. If you notice dark oil leaking from the exhaust, this is worth checking out.
First, remove the purge valve from the exhaust. Put a rag over the exhaust hole and rev the engine to purge the exhaust. This easy step will help remove anything in the exhaust that could be causing the burning oil smell.
Worn Valve Stem Seals
Over time the seals and parts on your ATV will wear down. If you have a bad valve stem seal, this could be why you smell burning oil. The most common way to tell if you have a worn out valve stem seal is on start up of the machine.
If the valve seal is worn there will be a little gap allowing oil to enter the combustion chamber on start up. If you start your cold engine up and see a big poof of blueish white smoke from the exhaust, you may need to replace your valve stem seals.
Gunk On The Exhaust
The last thing I wanted to mention before going over a leak down test, is to check that your exhaust is clear of debris and obstructions. It’s pretty common for a quad that has been sitting to have critters nested in there. Also, dirt, mud, leaves, or other debris could be lodged up against the exhaust.
The exhaust gets pretty hot while riding, and anything touching it will slowly burn, giving off a bad smell you could mistake for burning oil. Check the area between the exhaust and the heat shield for build up and clean it out.
Perform An ATV Leak Down Test
If you think you have a worn piston ring or damaged cylinder wall, perform a leak down test to make sure that’s what the problem is before starting costly repairs you may not need. The cylinder wall can get scratches in it from sand particles that get past your air filter.
With a worn out of scratched cylinder wall, oil could be leaking from the engine into the combustion chamber and burning when your engine burns the fuel air mixture. The same goes for worn out piston rings.
A leak down test is simply checking if your engine can contain the amount of pressure it’s supposed to. If it can’t, that pressure is most likely leaking out though your piston rings, head gasket, valve seals, or a crack.
To preform a leak down test you’re gonna need a Cylinder Leakage Tester Kit like this one from Amazon. You will find cheaper kits than this one on Amazon but I’ve had bad luck with the lower quality sets in the past. Don’t forget, you will need an air compressor, basic tools, rags, gloves, and safety glasses to complete the test.
The first thing you will need to do is clean the quad up to work on it and remove whatever parts you need to gain access to the spark plug. Next remove the spark plug and get the engine into top dead center compression.
In my case, I just needed to remove the timing plugs and rotate the motor until the timing marks lined up. If that won’t work for you, it’s best to refer to your service manual on how to get the engine to top dead center compression. You could also try to pop off the valve cover and make sure you’re on the compression stroke.
The kit I linked to above has three adapters, find the one that fits your spark plug hole and thread that into the where the spark plug was. Be careful not to cross thread it and make sure the o-ring seats nice and tight.
Now you’re ready to perform the test. You may want to get a breaker bar and someone to hold it because you really want to make sure the motor wont turn over on you when you pressurize the cylinder. This isn’t necessary, just a precaution.
Set the cylinder leakage tester kit up for the test. There may be special instruction on how to set the tester up depending on which leakage tester you’re using. Now you’re ready to hook the tester up the engine to find a leak.
If you can find the specs in your service manual then use those. But in general, you’re looking for a less than 10% leakage at 100 psi to confirm you have a healthy engine. If you see more than 10% leakage on the tester you may have a leak somewhere.
If you hear hissing out the exhaust, this may mean your exhaust valve is leaking. If you hear hissing near the intake, it could be your intake valve. If you see bubbles near the radiator, you could have a worn out head gasket. Finally, check the crank case, if you hear hissing, it could be bad piston rings or even a crack.
Is It Safe To Ride If My ATV Is Burning Oil?
The danger to you physically is very minimal, so I would say yes it’s safe. But it’s not really good for the engine. If you’re burning excessive amounts of oil, something is wrong and will only lead to more problems if you don’t get it fixed.
Plus, with an engine that burns oil, there’s more of a chance that you will be riding too little oil in the engine. Which will cause major problems with your engine in a short amount of time. If you don’t care too much about the quad, just keep the oil topped of and you can still ride it safely. But if you want your machine to last, it’s best to find out what the issue is and fix it as soon as you can.