Whining noise when car start up. No leaks. No engine light.

ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.

ANSWER : Hello, thank you for writing in. Shaking and vibrating typically comes from a misfire, or poor engine performance. A lack of oil will absolutely contribute to these symptoms and amplify them, if not cause them to begin with. You want to turn your attention to the cause of the oil leak. If external (you can see the leaking oil), then you will want to trace the leak to the component which has failed. If the leak is internal (or the engine is consuming oil), the leak will be harder to find. It will also explain the poor engine performance due to excess oil in the combustion chamber. A head gasket is one of the main components that will fail and cause these issues. It is however not common for a vehicle this age to have these kinds of problems. You will also want to scan the computer, and see what codes are triggering your check engine light. These diagnostic tools will help you determine what system(s) is to blame for the malfunction. For more diagnostic help, contact our service department to schedule an appointment.

ANSWER : Hi there. It is possible that the battery cable came loose or the wires to the oil pressure sensor has came loose or failed. Check the battery cables and make sure that the terminals are tight and clean. Check the wires to the oil pressure sensor and make sure that they are connected and not broken. If everything looks good, then the oil pressure sensor may have failed. Plus, check the computer for codes and see what is stored. This will lead you to the part that could have failed. I recommend replacing the oil pressure sensor then checking to see if the lights will go out. If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from Your Mechanic, that can assist you with the warning lights that came on.

ANSWER : Hello,
There are a number of things that could make an engine noisy when starting up. Depending on the specific type of sound you are referring to, this will determine how to properly diagnose. If there is a bit of a hissing sound, this may be a sign of a vacuum leak. If this is more of a shrieking sound, this may be a sign of a worn out or out of adjustment serpentine belt. If there is a bit of a howling or growling sound, this may be a sign of a worn out or low on fluid power steering pump. A rattling or pinging sound may be caused by an ignition problem. An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). A clattering type sound may be a result of improper lubrication in the valve train which could be a more serious problem and should be addressed as soon as possible. I would suggest having an expert from YourMechanic come to your location to diagnose and inspect your vehicle to ensure everything is in proper working order.

ANSWER : This may be a result of a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. Since this valve is controlled by the vehicle’s computer, it will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your idle air control valve.

ANSWER : Of course, don’t switch gears without being fully stopped, unless your Owner’s Manual or the manufacturer has alternative advice. However, the gear shift issue has no relation to the no-start problem you are describing. Inasmuch as you only have 6,000 miles on the car, the "constant on and off" that you believe has occurred is meaningless in comparison to the expected total vehicle service life. That is, assume what you perceive as "constant on and off", during merely 6,000 miles, might be equivalent to using the car "normally" for three years. A new car should be trouble free for at least 5 years, unless there is a defect, so your "constant on and off" is not a causal factor for any fault on the vehicle. What you might have is a defect in the ignition switch, or perhaps the immobilizer system, but if the problem is not in the switch itself, clearly there is an electrical problem.

If your vehicle is under warranty, by law the dealer MUST repair the issue you are describing within a prescribed time frame and number of "attempts", otherwise the dealer will run afoul of Federal and state Lemon Laws that give you very specific rights, and recourse (contact an Attorney; we are Mechanics, NOT attorneys). Consequently, if the vehicle is still under warranty, to save yourself money do be sure to seek a resolution from the dealer. If the vehicle is not under warranty, obviously a certified Mechanic from YourMechanic could identify the electrical fault and resolve this for you. If you want to go that route, please simply request a no start diagnostic -electrical system 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.

ANSWER : Hello there, you have a long series of issues going on with your 2013 Hyundai Sonata. If you keep getting a repeating oil light on than there is likely a fault in that system.

Since this fault has lasted after the engine was replaced it could be a oil pressure sensor, wiring harness fault, ECU fault, oil pump, oil strainer clogged, or low oil pressure.

To diagnose this issue properly you need a complete vehicle inspection to start from square one and identify the root cause of all this.

ANSWER : Your car has what is called a "safe mode" that will be engaged by the computer when it detects that something critical has gone wrong related to any of the major components in your engine chassis or power train. This may be related to a number of things, most of which should have been registered in the computer when the check engine light came on. I recommend having an expert from YourMechanic come to your location to inspect your check engine light and diagnose any codes registered by your vehicle’s computer.