Bad knocking from top of engine...won't start

Welcome to Prius Chat .

Some questions:

• Were there any dash lights displayed on the dash?
• Do you have a way to read trouble codes?
• Any recent maintenance performed?
• When were the spark plugs last changed?

You get the idea.

Good luck and keep us posted .

 

I’d pull the plugs and take a look at them along with any connected bits.

Also check to make sure your engine coolant level in the radiator is full.

See where that takes you.

What are you using to pull the codes? While everything so far seems on the engine side, if you have access to Techstream that would be best to ensure you are getting all the information.

Good luck and keep us posted .

 

The knocking might be from a loose spark plug. The misfires are bad plug(s) and or bad coils. If you feel like you can invest maybe a couple of hundred bucks, I'd suggest getting new coils and new iridium plugs and see if that resolves the problem. In the meantime, you can check the gaps on the plugs and see if one of them is leaking--loose. Rock auto probably has NGK or Nippon Denso coils and plugs, which would probably be OEM.

Have you or your wife been pretty proactive in changing the oil & filter and checking the oil? Synthetic oil helps with long term wear, btw. If all else fails, have it towed to an independent hybrid shop for diagnosis.

At 320K miles, you certainly have gotten your money's worth!

I've gotten 92,000 out of a set of iridium plugs on a ford V8, but at that point, the misfire was pretty awful and the mileage improved about 20% after a comprehensive tune up.

 

Unfortunate situation, but good choice IMO.

Damage is done. I'm totally guessing here, but my gut thinks the timing chain may have worn to the point is skipped, causing piston to valve contact. If so, you will find very low or no compression, mostly equal on all cylinders.

 

Is the IC an interference engine? If what you suggest is the case, would a piston hit a valve?

I think it's still prudent to investigate ignition faults

 

Yes, yes and agreed.

 

Well there’s your problem .

That plug looks spent .

The Autotel is a decent scanner, but with a gen1 and high mileage with a car the wife still loves, I’d improve my technology to keep her happy.

Not sure where the hv battery state of charge was left, but just be wary of starting the car too many times as you are in a pitch count until the battery is below what it considers enough juice to go.

Good luck and keep us posted .

 

I would get new coil boots and a tube of dielectric grease while you are out

 

For the Gen3 it is 15 foot pounds.

I would assume the same.

 

Pleasure.

Good luck and keep us posted .

 

DO NOT do that. The Tq listed for sparkplugs is almost ALWAYS for DRY threads. In the old days of iron heads and steel plugs, it was not that big a deal; today with Ni coated plugs and Al heads, not only is there no need for that cr@p, it can cause damage to the Al threads.

No OEM uses anti-seize on plugs from the factory, they do not get rusted in and do not gall, when changed at the recommended interval (the fine-wire pencil plugs in 3v Fords are an exception, but it is not the threads that are the problem).