Hello,
I recently bought a used 2018 Hyundai Sonata SE (Theta II 2.4L 4 Cylinder engine), from a Toyota dealership. I´ve owned it for almost 6 months. It had around 60k miles on it.
For starters, I am NOT a heavy/fast driver. But about a few months after buying the car, I had noticed the engine ran low on oil about 2000 miles after an oil change from the dealership. I had topped it off with 1 quart of Valvolines R+P before changing the oil with full syntethic oil after 700 miles.
At around 65k miles, I had notice the oil had fallen below the ¨L¨ line, this was when I started suspecting excessive oil consumption. I topped it off once more with Valvolines Restore and Protect Full Synthetic oil. Once I hit 66k miles, or around 2700 miles since the last oil change, I did another oil change but this time with Valvolines Restore and Protect, hoping it would do something.
I suspect it could possibly be a PCV valve issue that may be causing the extreme oil consumption but I may be wrong, I am no mechanic. I am aware these Theta 2 engines are complete garbage and are known for their oil consumption issues after buying the car. But as of now, I am not sure what to do.
The POSSIBLE engine knock comes at different times however. It does not make the noise when idle, only when accelerating around 30-75 MPH. Some days it makes the knocking/rattling noise, some days it does not. The car does not rattle, vibrate, or shake when accelerating. I do not suspect it could be low oil as it made the same knocking/rattling noise after my oil changes.
I have taken the car to the dealership for other unrelated things and they have done multi point checks but not specifically in the engine, but they did not see anything that could´ve alerted them. So I suspect it may be something internal?
Any tips and advices will be VERY helpful!
Those cars are well known for burning oil as well as total engine failure, transmission failure, fires, and other expensive issues due to poor quality. Really the best course of action if possible would be to get rid of it.
https://carkiller.com/scottykilmer/qa/hmg/
Changing the PCV valve may help the oil consumption so it is certainly worth doing. It's an easy, inexpensive job on most cars.
Valvoline's "Restore and Protect" is mainly marketing. Basically it appears to have more detergents for cleaning carbon deposits. (It might help if your oil burning is being caused in whole or part by carboned-up oil control rings.) While that can be a good thing the oil certainly will not "restore" a failing engine. Neither will any other additive that makes such claims.
Unfortunately since you are not the original owner Hyundai's long-term drivetrain warranty does not apply. Hyundai does consider oil consumption of a quart every 1000 miles to be "normal". So monitor your oil consumption and stay on top of it, bearing in mind that the manufacturer considers a certain amount to be expected.
As far as the possible knocking there are many things that can cause noises appearing to be coming from the engine. You might want to have a mechanic check it out. (You did not state if you had a mechanic check the car out before purchase but that should have been done.)
You might also try sending an oil sample out for analysis. I would expect that if you are actually experiencing engine knock due to worn bearings that worn metal would show up in the oil. You could also check oil pressure. Worn engine bearings will generally cause low oil pressure due to increased clearances.
Do you think scams are so prevalent
Of course. You didn't notice? Counterfeiting is a HUGE problem. Companies issue PSA's about it all the time, because counterfeit parts are everywhere! spark plugs, oil filters, air filters, ... you name it. And eBay is rife with it because nobody regulates it. The part just comes straight from China. Some people will make a buck wherever they can.
A few years ago there was a big scare because counterfeit parts somehow made their way into the aviation industry.
Always buy from reputable sellers. If the price seems too good to be true, it probably is.
https://www.youtube.com/watch?v=FiuYj-xufn8
https://www.youtube.com/watch?v=l1-a7Va8Ot8
When you change your PCV, make sure you get the OEM PCV. The dealership is going to charge you the most for it. I lucked out calling my dealership and the man himself to told me to get on Ebay for it.
If you try to buy it from AutoZone or etc., they'll probably give you the discount version and it'll cause you more problems.
Scotty has said it before, OEM PCV matters. It's a little bit extra but the alternative is gonna have you wasting money and time on the wrong thing.
I blew through 3 discount PCV from AutoZone thinking I bought duds or I'm messing them up how I'm handling them or something - only to find out how much the OEM part matters.
@bingray how did you ensure the part you're buying on eBay is the real thing?
@imperator
Mine was OEM Motorcraft and the model number was correct.
@bingray how do you know it was really OEM? counterfeiters can put whatever numbers they want on it.
Man I kinda didn't know that. But mine works and my car got better. This is starting to sound like I just lucked out.
The way my stock one looks, I got the matching one on Ebay because it looked and was labeled just like it. Car has genuinely ran better ever since I got it.
Do you think scams are so prevalent you shouldn't get on Ebay?
Also I lucked out and my car didn't blow up lol it got better. Which is exactly what wasn't happening with the wrong Duralast or whatever the AutoZone ones were
*Note: first time I ever edited a comment and it looks like it's about to not include the first thing I said so I'm copying it here
"Mine was OEM Motorcraft and the model number was correct."