(Context-for about 5 months I've been hearing a strange noise when starting up my 09 g37s, but it would start and drive just fine. I had also been experiencing engines misfires because of bad spark plugs, along with a service engine soon light. Never a triangle though, even now. My battery would also die very quickly for an unknown reason. it would happen within two or three days of not driving and using the alternator.) One day my car started making a strange noise on the interstate going around 70-85. I wasn't sure if it was mine because there were a lot of loud cars near and in front of me and sounds got mixed up. I continued to drive and my oil light started to flash every 10-15 seconds or so. Eventually when slowing down due to road work, I went into limp mode and pulled over. I heard the noise more as I slowed down. I tried turning the car on again and it wouldn't turn over. I checked everything in my engine bay and my oil was low. I had a quart in my trunk and putting it in had it about 1/3 on the dipstick. try'd jump starting 3 times and it didn't budge. towed it back home and started researching. The obvious problem is Is I was riding with no oil and messed up a piston or the whole engine. But here's the thing, when I did an oil change afterwards, at least 3 quarts came out, and the oil didn't look to bad. so youtube told me it could be a broken cat, replaced those, still making the noise. The next thing on the list is the starter because I think it could be loose and causing a rattling noise. Im at a loss and I really don't want to put money into anything else that doesn't need to be fixed. I've also heard it could be a broken hose, or a loose belt. haven't dove to deep into any of those. I could really use some advice or just ideas. If I need to replace my engine someone needs to give me the cold truth. Thank you for reading all this. Ill post a video of the noise and me trying to drive it soon.

 

The cold truth is no one here can tell you what is wrong with your car unless we are able to visually inspect it. It will all be guessing games even though a video might help out quite a bit.

That being said I would be extremely surprised if you don't have a spun bearing. These cars have some real bullet proof engine with proper maintenance but run hot as well.(on the oil side not the coolant).What I understand is you where running the car on two quarts of oil for some time at relatively high speeds (rpms)which would of made the engine oil extremely hot maybe causing it to go into limp mode.

The extra quart you added ,then when changing it having about three quarts.
I know these engine are sensitive to types of oil (must be ester)as well which maybe not having enough could of been causing the rattling as well .

keep up posted, hopefully it can be fixed

 

Now that the dust has settled and everything has cooled down, does the engine at least attempt to crank (turn over) now when you try to start it?

Like Birdie mentioned above, it will be nearly impossible for anyone here to properly diagnose your issue as we can't physically examine the car. That said, you were driving at high speeds (70-80mph/3-3500 engine RPM) and was VERY LOW on oil. Crank bearings, cam journals, VVEL (to name a few conponents), everything relies on oil.

I am not going to beat you up. These engine are damn tough and have a proven rate of reliability, but they are not immune from poor maintenance or neglect. No engine is. Keep in mind that by the time the idiot lights/ bells/ whistles go off, sometimes the damage is already done.

Find a qualified mechanic and have them properly diagnose your issue. If the crank won't turn- either by hand or the starter, then likely the engine has seized. Again, only guessing. In the end, you will probably be better off replacing the engine for a newer one anyway (if you plan on keeping the car).

 

haha that's definitely the cold truth. I took a video of me starting it up. Maybe the sound will help diagnose it. Also I would probably get a new engine installed, if it ends up being cheaper than a new car.

 

Here is the video of the start up and knocking noise. Also I should add that a little bit of smoke was coming from the engine. It was white, could have been the exhaust, or just the hot engine in 50 degree weather.

 

Never mind the video isn't posting. Thanks for the fast answers, Ill post the video after work.

 

Will wait for the video but if the engine is knocking then that is not a good sign. Could be any number of issues with the rotating assemblies. The "smoke" could be condensation burning off or something more serious like a cracked block or water jacket.

Again, we are all flying blind here. Best advice would be to get a good mechanic to inspect the car- one who knows these engines!

If it were me, and you plan on keeping the car, I would strongly consider just replacing the engine. These engines can be found used and in next-to-new/low mileage condition for <$1k.

Just my 10¢.

 

Alright, sadly im not made of money so I’m going to be out of a car for a while more. Any idea how to find a traveling mechanic? No one seems to want to do it for me when they here my issues haha!