Why am I going through so much oil?

After having a used engine put in my car a couple months ago my check engine light has come on and I'm having to put a quart of oil in about every 100 miles. The engine had about 63000 miles on it but came from a reputable company. I've had it back in the shop and they keep sending me home saying something about am oil consumption test. But also that there was oil in the tailpipe? I'm very nervous about driving my car like this. Especially since I've lost any kind of pickup in acceleration. What would cause this and what should I do?

My car has 97000 miles.
My car has an

Experienced mechanics share their insights in answering this question :
If you are using 1 quart for every 100 miles then you have a major engine problem. This much oil can get in through the piston rings, valves, and seals in the heads. You should have the engine checked for internal engine oil leaks. Oil consumption tests are to prove you are adding this much oil.

If you don’t want to keep going back to the dealer, consider YourMechanic, as a certified technician can come diagnose your oil leak and make the necessary repairs to your vehicle. Good luck.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

When a car mysteriously loses oil, there are usually two possible causes: either you`ve sprung a leak, or your engine is burning it away. Though you may not see any visible signs of leakage, less noticeable parts like a worn seal or leaky rings may be the culprit.
Burning oil is often the result of worn-out parts. For example, worn valve seals and/or piston rings could lead to your car burning oil. Both valve seals and piston rings work to keep engine oil out of the combustion chamber.
Under normal operating conditions, excess oil consumption is generally a mechanical problem. In the majority of cases where oil consumption problems have been investigated, it usually turns out to be a leak issue – either the valve cover gasket is leaking, crankshaft seals leaking, or one of the main seals is leaking.
In certain cases, the oil level may have risen since the last time you checked or there is too much oil on the dipstick. This could be due to condensed water (from combustion), condensed fuel or a coolant leak – all are causes for concern.
If your engine is low on oil but there isn`t a leak, that means it`s probably being burned inside the engine. A bad PCV valve is a frequent culprit in the case of burning oil–but what is it, exactly? A PCV valve is designed to let air escape when the pressure in the crankcase is too high.
However, a bad PCV valve is a tiny, inexpensive part that can cause an engine to burn oil if it goes bad. Replacing it is fast and easy! If your engine is burning oil, hope that it`s due to a bad PCV valve.
Oil consumption in modern passenger car engines is usually less than 0.05 %; the maximum permissible oil consumption stands at 0.5 % (all percentage values relate to actual fuel consumption). Normal oil consumption may be higher for older engine types, stationary engines and under special operating conditions.
To slow oil consumption, a higher viscosity grade oil can be used, especially an oil with a higher operating temperature viscosity. Oil burns when at its hottest and therefore thinnest viscosity.
Blue smoke from the exhaust: Bluish smoke can indicate your car is burning oil during the combustion cycle. Burning oil smell: A thick burning oil smell could mean oil is seeping onto hot engine parts. Frequent low oil light warnings: Regular low oil warnings can indicate excessive oil consumption or a car burning oil.
Depending on the make and model, “normal” oil loss between changes can be as much as one quart of oil every 700 miles.
It is a fact that most engines will burn some oil. The majority of manufacturers consider one quart of oil in the range of 1,500 miles to be acceptable. It should also be pointed out there are some performance vehicles that will consume a quart of oil in less than 1,000 miles and is also considered acceptable.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

lost all oil pressure, replaced the oil pump, low oil sensor, oil pressure sensor, oil pan gasket,
ANSWER : The fuel pump will not stay on if you loose oil pressure. This is why it is shutting off. The loss of oil pressure may be from bad crankshaft bearings or camshaft bearings. The engine oil pan should be removed and the oil pump needs to be checked to ensure that you put in the pick up tube seal to the pump and connected the pump to the block. Then remove at least one main bearing cap and inspect the bearings for excessive wear and crankshaft damage. If you need some help with this, consider YourMechanic, as a certified technician can help diagnose the issue with your oil pressure firsthand and help you fix it accordingly.

car burning too much oil and can’t find where it’s going
ANSWER : The engine is sucking it in most likely. The oil control rings are bad or the intake valves are leaking. You should have a mechanic check the intake PCV system to see if there is a problem. After the diagnosis of your leakage, a certified mechanic can make necessary repairs.

Hello Ben, my oil pressure is came on. Slight oil drip. Mechanic changed oil, replaced sending unit. Light came on after a day.
ANSWER : You need to have the oil pressure checked to see if the oil pressure is within specifications before you condemn the engine internal problem with oil pump or crankshaft and bearings. You may want to get the dealer involved now and let them take care of getting the light diagnosed.

Oil still leaking after I changed oil filter
ANSWER : Unless there is an imperfection (e.g., serious pitting or irregularities) on the engine mounting base for the filter gasket, the leak is probably not at the filter. There are other adjacent potential leak spots such as the oil pan gasket, oil pressure sending unit and so forth. If the leak is significant at all, merely thoroughly cleaning the suspect area and running the engine while looking for the leak should be sufficient. If you still can’t find the leak origin, a UV visible dye can be added to the engine oil which will then make the leak point visible using a detection light. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an oil leak diagnostic and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

replace oil pump and pick up tube
ANSWER : Hi there. Typically when the oil pressure changes based on the type of oil you are using, it’s an issue with the pick-up itself. Quite often, the wrong sized or style of oil pump or a pick-up line that is too short / long, can cause inconsistent oil pressure. It’s also possible as you indicated that the oil pickup screen is clogged with sludge or debris (especially if the engine has not been rebuilt). It might be a good idea to have a professional mobile mechanic complete an oil pressure light inspection to help you pinpoint the source of the issue and recommend the right repairs.

Oil consumption. Burning oil. Oil light turns up on idle.
ANSWER : Hi there, thanks for writing in. The valve stem seals are the most common cause of this on your engine. When they fail, it requires that the cylinder heads be removed and rebuilt to fix it. The piston rings can also cause this but they are not as common. Unfortunately there is not anything, not even heavier oil that will fix this. You will need to have the heads rebuilt.

My car is leaking oil i got an oil change for it last month but it is still leaking oil what will cause my car to leak oil ?
ANSWER : Most older cars have oil leaks. Sealing technology has just not kept up with mechanical improvements to engines so much so that leaks often kill engines rather than mechanical problems. So, it is not unexpected at all to have an, indeed many, oil leaks on a 23 year old car. Oil leaks vary hugely in terms of severity and priority of repair. Oil leaking onto a hot engine manifold is the worst case (the oil can start a fire; at best, you are left breathing oil fumes in the cabin, as the oil burns off of the manifold) while de minimus seepage of oil at the oil drain plug or oil pan gasket, while annoying and messy, if limited enough is not an emergency. Some leaks are easy to repair, while others literally require the engine to be removed just to get physical access to all the leak points. In your circumstance, if you smell burning oil, oil is probably leaking onto a hot engine part such as the exhaust manifold. A certified Mechanic, dispatched by YourMechanic right to your location, can perform an oil leak diagnostic and then let you know of your repair options and costs.

As far as the check engine light, that is not related to the oil leak(s). If you request a check engine light diagnostic, a certified mechanic from YourMechanic would use a code scanner to retrieve the specific diagnostic trouble code(s) from your car’s PCM that have caused the check engine light to illuminate. Using those codes, the appropriate individual vehicle components or sub-systems (often a sensor, circuit, and the like) are then carefully tested, based on specifications set forth in your car’s Factory Service Manual, to pinpoint the cause of the fault or the reason why the check engine light has illuminated. Once the faulty part or component is identified, it is explained to your satisfaction and the mechanic will let you know of the cost to repair. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Just noticed a huge oil leak trailing my car. It seems to be coming from below the engine. I recently had my oil changed a month
ANSWER : You might have a problem with the oil filter leaking when you rev the engine and increase the oil pressure. This can be from a collapsed oil filter media or excessive oil pressure from the engine. I recommend having the oil and filter replaced using a good quality filter and have the oil leak verified to be from the filter. Make sure to not run the engine low on oil. If you are finding you do not want to drive with the leak, a mobile technician from YourMechanic can come to your home or office, and replace both your filter, and oil.