Possible Engine Issues

Currently working on a friends 2011 Prius with roughly ~340,000 miles (!!!!!) that was used as a taxi, until now, he bought it from the taxi company and converted it his own daily.

I did a regular oil change on his Prius, and decided to change the spark plugs as at the time there was some sort of occasional shaking/rattle at cold startups. The shaking was gone after changing the spark plugs. This was all done back in March. Yesterday, he was driving, and all of a sudden, the knocking came back, a check engine light, and white like cloud smoke appear. Check Engine lights were P0300, P0301, P0303 (misfire cylinder). I told him to bring it over, I took a look, and his invertor engine coolant was all the way down (he told me he filled it up to top just two weeks ago). I originally thought maybe it was the ignition coils (for shaking), but the white smoke didn't make sense. So I purposely filled the coolant above the full line, and took it out to drive for about half a mile, and just as I suspected when I opened the hood, the coolant level decreased, at least by an inch.

I did not see any oil leaks, and the oil levels were just fine. The car just seems to shake/rattle at startup and when accelerating at low speeds (roughly 8 - 15 MPH) and than goes away, and drives normally. It still does blow off that white/cloud smoke when accelerating hard on the engine though. As for the smell of the smoke, I can't really tell, it is definitely not sweet, but it kind of smells foul/bad.

At this point, I am pretty sure this engine is gone, and the gasket/seal is blown, but I am pretty sure that's a $2,000 - $2,500+ to replace or fix the engine, and he didn't even buy the car for that much lol.

So, I wanted to ask here, has anyone experienced this kind of issue on a Prius, and ever attempted to fix it, rather than replace the engine? My friend really wants the ignition coils replaced as they have already been bought, so I'll install them for now, but not sure if it is even worth it, since the coolant is clearly leaking, or "disappearing" (no actual drips anywhere). I think it is most likely a blown seal, but again, no idea if that is a good assumption to make as I don't want to start tearing up parts just yet. I am open to any ideas or pointers to possible solutions.

I was also curious if the Bars Leaks would be good for this kind of scenario as a temporary solution. My friend does use this car as a daily, so I wasn't sure if it was a safe and wise idea to trial with it before asking here.

 

When you say to clean out the entire engine system and intake manifold, do you mean like a major flush of all the liquids?

 

Do you know if this kind of test is available at AutoZone, or would it be a paid checkup? I am pretty sure its coolant, since their is no engine oil loss.

 

Ah okay. Any idea on where I can get the exhaust test for cheap? I've been calling around and no one seems to understand what I am asking for, is there a fancy buzzword for it?

Does anyone know if anyone here ever replaced the seal itself? I asked around few places, and a lot of them confirm that with the high miles on the current engine, the seal is most likely gone. For now, the car is sitting in my driveway, but my friend really doesn't want to put a new engine because of the costs, and rather would fix whatever the issue is, and than save up to swap the engine.

 

Quick update - We didn't change the ignition coils at the end, I instead talked with a mechanic who said he is willing to do an engine swap for roughly $1,600.00, the engine has roughly 150,000 miles on it already. The other alternative of course is a low miles engine but thats north of $3,500.00. Since this is going to be a daily driver, I think my friend might go with the cheaper option, as he needs the car running ASAP. We have a few days before we go with the swap, but was wondering if anyone had comments before we do the change?

 

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