My daughter's 2004 Prius developed an engine noise and rough running that turned out, according to the dealer, to be a spark plug that broke off inside the engine. They replaced the plug, but don't know if the pieces are still banging around in there and whether they will cause engine damage. I haven't seen the old plug yet. They were replaced a few thousand miles ago with genuine Toyota plugs. Any ideas on this? Thanks, Gregg.
Change the oil and put a magnet in the oil pan. It may be "old school" but metal and magnets have an attraction. If the ceramics are in there I would do more research because any foreign material can cause catastrophic engine failure...
Ouch! That's not good. Definitely look at the old plug - if it's the electrode you may be able to retrieve it with one of those "magnets on a telescoping antenna" doo-hickies, through the plug opening. But if it's the porcelain insulation, I'm not sure how you would get that out. I think its more likely to be the latter on a new plug - maybe defective, or cracked on installation.
It probably went out threw a exhaust valve. You would hear it if it was on top of the piston? Monitor your oil closely for awhile. Good luck,H
Gregg, if the plugs were changed a few thousand miles ago any old plug remnants are long gone and any damage that could be done is done. If the car runs ok and oil consumption didn't increase, relax and enjoy the car. If there are no obvious problems, odds are that no serious damage was done. Thee are scopes that let you look inside the cylinder through the spark plug hole. You might be able to see some dings in the piston top but if you do, it won't help you so you might as well forget about it.
Run the engine for a short time with the plug of that cylinder removed. It makes a lot of noise but will blow out any objects in the cylinder that haven't found their way out through the exhaust. There is no way for spark plug bits to get into the sump.
Spark plug pieces can't get to the oil pan unless there's a hole in the piston (which means catastrophic failure). You may want to find a shop that has a boroscope. They can remove the spark plug, stick a camera in there, and see if there's anything in there. But if your engine sounds like it's running fine, and you're not getting a misfire code on that cylinder, you might have gotten lucky. Hopefully it blew out the exhaust before damaging anything on the way. I had an old pickup that once lost pretty much ALL of the end of the spark plug, tip, ceramic, electrode, basically everything but the threads and outer exposed half of hte plug. I bought the truck that way expecting to have to rebuild an engine, but $1.29 later I was done. I didn't have a scope, but I duck taped some clear polyethene tubing to my shop vac, stuck it in the spark plug hole, and vacuumed around for a while. Nothing got sucked out. The engine ran just fine afterwards. It was an incredible stroke of luck.
sounds like the dealer who replaced the plugs awhile back should pay to remove the head and clean things up a bit. let them chase toyota if the plug was defective.
Who replaced the plugs last time Gregg? Was there anything troublesome noticed during that spark plug change?
The last thing I would want would be to have a dealer's shop remove the head on an engine that is running properly.
My daughter's boyfriend (and I) did the plug change last summer- everything was fine at the time and the car ran great until a week ago.
As already posted, if you still hear something banging around in there remove the plug and let the HSD crank the engine. Be sure you are not looking down the hole and be sure you are wearing safety glasses. The bits will come shooting out the spark plug hole. If you don't hear anything banging around in there and the engine idles fine, it's fine. Don't fix it as it isn't broke!
1. I understand that you replaced the spark plugs with the correct NGK or Denso plugs several months ago, and apparently one spark plug had a piece break off, one week ago. 2. I would like to see a good, sharp photo of the broken spark plug. 3. Does the engine run well now? If yes, then don't worry.
It seem to be very unusual for spark plugs to break like that, *other* than when they're being installed or removed. I've never heard of that happening before.
