The flash point of your motor oil is one major factor in consumption the more diluted the oil is with unburned fuel the lower the flash point becomes, the easier it is for oil in the combustion chamber to be burned and head out the exhaust with the rest of the byproducts of combustion. As the internal combustion engine doesn’t achieve 100% combustion as its not 100% sealed it can never not use some oil as part of the combustion process.įactors that can increase oil consumption are engines that don’t always reach operating temperature, vehicles that have “slow” front air fuel sensors or anything else affecting fuel trim allowing the car to have an excessively rich fuel mixture or problems with the 2 different crankcase ventilation systems. When I worked at the dealer we dealt with new Subaru vehicles that used some oil from day one, and unless it was more than a quart every 1000 miles there were never any warranty repairs authorized. Prior to that Subaru used a low oil pressure light, but typically no oil pressure means the damage has in fact been done. The key here is to know your car, and know the point at which it may use a little oil and stay on top of it! If you don’t check your oil how will you know if it’s low? Until the current era Outback limited models there has never been an oil level sensor on a Subaru. Some engines won’t use a drop of oil until the 2500 mile mark and then use a quart in a few hundred miles this is mostly because of the dilution affect of the oil in the crankcase which I will address in a bit. Just like the more you walk in your shoes the quicker the bottoms wear out until one day your foot is wet, one day you will check your oil and it will be low where it hadn’t been before, this is the critical point in used vehicle ownership where staying on top of your maintenance aspects will avoid costly repairs, and not will mean a new engine. As the engine ages it will reach a point where the piston oil control rings can no longer expand enough to slow the consumption of oil, the engine wears a little, every day you use it. This is a completely normal thing to happen in an internal combustion engine, and as long as the engine isn’t repeatedly ran low or worse out of oil, it won’t really affect the performance of the vehicle. ![]() Why is this important? Over time the internal components of your engine such as the piston oil control rings, valve stem seals, valve guides and cylinder walls can all wear to the point where more oil is actually introduced into the combustion chamber than originally designed. If you’re a good car owner you DO periodically check your oil, I suggest every other tank of fuel, but it’s actually suggested by Subaru to do so every tank of fuel. ![]() For this article I am focusing on oil consumption and not external leaks from the engine, meaning if you check your oil, find it low, it’s not due for an oil change and there are no major visible leaks found with your engine, than this article applies.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |