Broke down-told I need a motor

[vandem531]

I have a 2012 Subaru Legacy. It only has 93k miles on it.

 

It broke down last week: shaking horribly and the check engine light, break light and rotation light came on.

 

I took it to my usual mechanic and he said I had carbon build up in my engine and I would need a new one. He also mentioned he scoped my engine and that's how he found the carbon on my Valves.

 

I also know that all four of my cylinders misfired.

 

I honestly don't think my engine is bad. I also know nothing about cars.

 

I had my cousin who is a mechanic look at it. He said he doesn't believe my motor is bad because it would be making a ton of noise. All mine does is shake. He also mentioned that my valves would be making a ticking noise and they don't.

 

He said it could be electrical.

 

I'm not really sure what to do. I still owe $8k on it and I was going to trade it in but it's hard to go to a dealer without them noticing it. I had all the codes cleared and the shaking went away. They will most likely come back on in 50 miles or so. And when you rev my car, it doesn't hesitate.

[JF1GG29]

Did you get the code written down before you cleared it? The car runs fine after the code was cleared?

[vandem531]

I didn't get the code but it ran fine after it was cleared. I also remembered that that same mechanic put conventional oil in my car back in the fall and I found out and told him to go back to synthetic which I've always had in it. I also called subaru and they said the issues could be from the wrong oil.

[JF1GG29]

Sounds really weird like something is missing from the story here.

[GTEASER]

Moved to 5th Gen section for more exposure.

 

What model car and transmission do you have? Where do you live? Filling in the info in your user profile will help other members help you.

 

What were the codes? What maintenance has been done on the car?

[cww516]

For the record, you're not going to blow up your engine by putting conventional oil in rather than synthetic. Assuming you have a 2.5i, synthetic isn't required for 2012 (only recommended), and the EJ253 isn't a particularly high-performance engine that will only run if it's filled with oil from solid gold bottles, so as long as there was oil in it, you're fine on that front.

 

Carbon buildup sounds like it'd be something that would come on gradually rather than all at once, and it's not likely to damage an engine permanently. I'm guessing that if he scoped all 4 cylinders, your mechanic looked at all 4 spark plugs to make sure they were still good, but just in case, when's the last time they were replaced?

 

Misfiring randomly across all 4 cylinders isn't something I'd expect to start out of the blue, and you'd probably get a pretty healthy shake going if you just had one cylinder that wasn't firing at all. If that's the case, it could just be a bad coil pack, and those are substantially cheaper to replace than the whole engine. Like GTEASER mentioned, having the codes read will help a lot in diagnosing the issue. If your cousin has a code reader, he can see what cylinder is misfiring and switch coil packs between cylinders- if the misfire follows the coil pack, you've found your issue.

[YeuEmMaiMai]

carbon buildup does not mean new motor. it means you need an induction cleaning and some detergents added to your fuel. My favorite is Seafoam ATF additive. that stuff will clean out the carbon on your intake valves in no time flat.

 

put half the can in your gas and using the brake booster line pour the other half into a squirt bottle and stick the nozzle in the booster hose with the car running and squirt away

[cww516]

That too- assuming you haven't let it get so bad that the carbon buildup is causing knock (it can get good and hot, and cause the fuel/air mix to ignite before the spark plug fires, but you almost have to try to have it get that bad), you can just clean the carbon deposits out and be on your merry way.

[WheelZ]

Check your coils as well for the misfire. They may be smoked.

[FLlegacy]

Also have your battery checked, these cars do some very odd things when the battery is going bad. I would start with a obd2 scan to see the active and pending codes, then move on with that information.

[nads]

Don't clear codes until your writ them down. Codes help guide you to possible cause of issues.

 

What was the situation when you broke down? As in engine was cold, fully warm, cruising down the interstate, drag racing a jazzy, etc. Anything seem or feel odd before the issue? How long have you owned the car?

 

I'd find another mechanic and as stated post you location, a local member could be helping you out if they knew you were in their area.

[vandem531]

I got something similar to seafoam that our other mechanic whose really reliable. I also took it down to someone else for a second opinion and the lights never came on until I drove 10 miles and they were only on for 3 seconds and turned back off but it was still shaking when I came to stops.

 

And just some info on the situation, I was going up a big hill but luckily was a mile from my house so I took it straight there not to worsen it by driving. I'm also upstate New York so when it's cold, it affects my car battery. We actually had to jump it last night and it wouldn't turn over with a 200 booster box on it. Had to wait about an hour to jump it. That could be from not driving it. I'll find out what's up with it then I'll be trading it in cause it's caused me so many issues. I also had control arm bushings go so I had four new ones out in in October but that same mechanic said I had a "bar" that he forgot to put in my car so after I already left, I went back to get that part out in.

[dgoodhue]

I have a hard time believing that carbon build up made the engine misfire so bad.

 

I actually had an engine that had tons of carbon build up. Coincidently, it had 93k miles on it when I bought it. When I first got it one my friend noticed when driving behind me when I went WOT, it seemed to have a lot of carbon coming out of the exhaust. I did my best to try to clear out the carbon Over the next 20k miles, I end up with super high oil consumption; 1 Quart every 300-400 miles. The engine seem to run smoothly otherwise. I bought another motor and when I went to part out the original motor to part it out, their was carbon everywhere inside. In talking with more experience mechanics, they believed the excess carbon is what killed my piston rings. I have never seen a motor with that much carbon in the piston and heads. I drove that car pretty hard, so I can only imagine how bad my carbon was when I first bought the car. At the time I didn't know about carbon treatments, which in looking back I should have done.

[GEE-OTTO]

Seems to me like poor maintenance rearing its ugly head. Sad part is it will get traded and someone else will buy a turd.

 

And people wonder how those "I just bought a new Legacy and it sh*t the bed 10 miles from the dealer" threads get started.

 

Im somewhat disturbed that the OP would even tell us he is going to trade in a grenade but on the other all I want is for him to post the VIN se we could add it to the DO NOT BUY THIS LEGACY thread

[seiyafan]

Would using top tier gas or Techron reduce carbon build up?

[GTEASER]

An Italian tune-up would.

[JF1GG29]

Honestly, it sounds like your mechanic is the problem.