Engine and battery supposedly shot (but I'm skeptical)

I'll try to make this concise: I drove my car 1000 miles past the time it was due for an oil change, and one day I turned the car on to find a check engine light, and the big red triangle. I had the engine codes, and I will try to get them again and post them later in this thread.

I towed the car to a dealership that does repairs, and they told me the car, which was supposed to have 4 quarts of oil in it, was down to a half a quart. They said one of the cylinders was misfiring and one of the cams was in the wrong position, and that I was going to need a whole new engine. They also said the error related to the battery indicates the battery will also need to be replaced.

I had a bad experience with the dealership leading up to this, and I decided I didn't trust them, so I towed the car home, drained the oil, changed the oil filter and put new oil in the car.

When I turn on the car, I still have the big red triangle (which doesn't surprise me), and the touch screen indicates that the battery is very low. Before towing the car, I had run the engine for a few minutes and it appeared to charge up the battery.

I talked to three friends who work on cars, and they were all pretty skeptical of the dealership's diagnosis. However, none of them work on hybrids, so I thought I'd ask all of you for advice:

1. I don't know how I can troubleshoot the engine with this other battery problem. My friends said to clear the code, drive around on the new oil and listen for any engine problems. The engine never sounded bad before and the car does drive, but I'm worried that if I drive it to troubleshoot the engine, it'll die in the middle of the road because of the battery.
   
   
2. What if I replace the hybrid battery, and the car is still undriveable because of this oil issue? I got a quote for around $1,500, from Green Bean. I suppose the next step down from that is to buy a battery and install it myself (I see batteries on Ebay selling from around $450 to $800, but I don't know if theat's a good way to go). I could even go to the auto yard and pull some batteries out of old Priuses, test those for a charge and try one — but If it then fails quickly, that's probably a lot of wasted effort.
   
   
3. I have even heard of people identifying individual cells that are bad and only replacing those. I raised this question to the mechanic at the dealership, and he claimed that this was really dangerous to do at home.

If I'm asking questions that have been answered a million times, please just point me to the right threads. In the meantime, I will try to get those engine codes. Thanks.

 

thanks for the replies. If I understand you correctly, you're saying that going over-schedule is less of an issue than regularly checking my oil. I will admit that I do not check my oil between changes, so I will need to start doing that.

As for the codes, I only have two now: P0A80: Hybrid battery pack deterioration; and P3000: High Voltage Battery Fault, HV Battery Malfunction.

In the past, I have had another code. I think it was P0011: Camshaft Position “A” - Timing Over-Advanced or System Performance (Bank 1). I don't remember which bank or position, but I'm pretty sure it was this code. I was on the road and I had to park the car at this really weird angle, and I thought this threw something off with the car. After this, I was having a rough idle — but then, as I drove, it went away, and the code went away.

The mechanic did say something about one of the cams being in the wrong position, but I'm not getting that error code right now. All I've done so far is change the oil, and the oil filter, and idled the engine for a while. So, as of right now, the car is not detecting any engine problems—just the failing battery.

Thanks for the tip about the $1,600 DIY battery. Green Bean quoted me $1,400 for a reconditioned battery, with a 3-year warranty. I think I would be more likely to go with this, but I'm still interested to hear people's advice.

 

Oh, and the mechanic said there was less than a quart of oil in the car, and when I drained it, I would say yes, this was how much oil came out.

 

Thanks. I drained the old oil, changed the filter, and the engine is filled to the brim with clean oil. And since I'm not getting the code, I bet you're right that the cam issue was related to the low oil pressure.

I'm really surprised that the Prius wouldn't have a 'check oil' light. The lesson I've learned is to frequently check it myself. Green Bean is coming tomorrow to install a new battery. Thanks so much for the advice.