OP said it was genuine Toyota extended warranty
I think if he canât get any satisfaction from higher up the food chain, he needs to consult a lawyer.
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The piece written in tiny type, on the back of page 4, that says âWe reserve the right to interpret this contract in any way that suits us, as we shall from time to time determine, consistent with our best interests.â
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Thank you for confirming/agreeing that they are exercising the âWeasel clauseâ
The only spark plug porcelain cracking Iâve seen was from temperature shock . . after shutting off vehicle, plugs still hot, the remaining coolant system pressure pushed coolant through a head gasket onto the plug . .cracking it.
Every few months the misfire was exactly the same plug failure. . . cracked porcelain on . .ACDelco , Motorcraft , Autolite, whichever . .all had cracked porcelain . . none ever getting in the piston wall.
now that your engine is apart it would be pretty hard to tell if there was an existing head gasket issue that may have taken out the plug as a result.
the plug not being the cause of the engine damage . . but a result of coolant leaking upon it.
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I have seen porcelin tips break and score cylinder walls on several occasions. Most were the result of improper efforts to set the gap on platinum tip plugs, and more specifically Bosch platinum tips that were being heavily marketed by Auto Zone stores in my area. But yes detonation has been the apparent cause for several plugs dropping the hot electrode tip as evidenced by the damage to the piston crown. A plug electrode wonât knock out a nickel size piece of the piston but spark knock will.
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The warranty reads that spark plugs are not covered. I take this to mean that you will pay for replacement spark plugs, since they are maintenance items. However, the warranty covers the engine heads and block. The spark plugs are the original plugs and have never been removed from the engine. The 2011 Toyota Sienna does not call for new spark plugs until the 100,000 service point. I think the dealer is misinterpreting the warranty. I believe it means that if you decide you need new plugs at 99,000 miles, the cost of replacing the plugs is on you.
I still believe that coolant hitting the spark plug porcelain to break. The misfire triggered the check engine light. In other words a breached head gasket or hairline crack in the cylinder head caused the problem.
If the plug damage was caused by severe detonation, that is a problem with the engine computer controls. The Sienna does not require premium fuel. I have a 2011 Sienna and I have read the ownerâs manual. I have 84000 on my Sienna and it has the original spark plugs.
In an earlier post to this thread, I mentioned a 1990 Ford Aerostar that I once owned that had the same problem you are having. I purchased the Aerostar as a used vehicle from a used car dealer in 1991. It came with the balance of the factory warranty. When the engine developed a misfire, it was traced to a spark plug where the porcelain had a piece broken away around the center electrode in the firing tip. I was shown the plug, and was told that the new spark plug took care of the problem. That cured the misfire, but I told the service manager that I bet the real problem was still there. Six months later I was back with an engine that would misfire intermittently. The Ford dealer stripped the heads off the engine and found a crack in one of the heads. The spark plugs were o.k.âno broken porcelain. The dealer said that the cracked head caused the engine to run poorly. The service manager also said that a cylinder wall was scored because of coolant getting into the cylinder from the cracked head and the entire engine would be replaced under warranty. I got a new engine with no cost to me even though I didnât purchase the Aerostar from that dealer.
I would bet in your case that coolant from a breached head gasket or cracked cylinder head caused coolant to damage the cylinder wall and break the porcelain on the firing tip.
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Thanks Everyone! I went back to the dealer and inquired about all the different suggestions (especially the possibility of a coolant leak through a cracked cylinder head or something). It looks like they did not do a magna flux test to establish that the cylinder was cracked, but the dealer told me that there was no coolant leaking into the cylinder - he said that if coolant had leaked in, then the spark plugs would seem like they have just been steam cleaned, and that was not the case. Is that true?
Now hereâs the twist. I was finally able to convince them to pay for replacement of the short block, gaskets etc and associated labor, but not under the extended warranty. (This may only apply for people in California) Apparently, there is something called a California Emissions Warranty (which is stricter than Federal Emissions Warranty). The emissions warranty is a contract between the state & the car manufacturer that a failure of a specified list of emissions related parts will be replaced by the manufacturer free of cost. Spark plugs are actually covered under that warranty until their first required maintenance - which is at 120K miles for a 2011 Sienna. It was just a fortunate coincidence that I ran across this clause and was able to convince them. But, this is clearly something everyone should remember given that the manufacturers first reaction may be to try and avoid paying for repairs.
My only question to the dealer now is if I am going to see this again given that they were not able to identify why the spark plugs failed in the first place. @Triedaq should I still be worried about that given they are replacing the short block? I think they are still trying to reuse the cylinder heads.
Thanks a bunch everyone for the very helpful and enlightening comments!
Just my two cents but on several occasions it was explained that the drive train warranty covers anything touched by oil. I think they were on the hook for the new engine all the while, whether they wanted to admit it or not. I find it less than believable that the original problem was caused by a plug defect anyway and would not worry about this rare situation happening again to the same person in the same vehicle. I might think about a different dealer though.
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There should be no problem reusing the heads, but the head on the bank where the spark plug had a broken spark plug should be inspected carefully for a crack. In the case I had with my 1990 Aerostar, I had a problem almost from the begining. When I would first.start the engine it would idle roughly for 30 seconds to a minute. The dealer traced it to a bad head gasket that was replaced. When the problem returned a year later, the hairline crack in the cylinder head was discovered. The crack was probably a factory defect. In my case, I got a new short block and a new cylinder head. The other head was reused. I was covered under warranty and the used car dealer where I bought the Aerostar loaned me a car to drive. The only hitch was at the parking services at the university where I taught. I had to pay $30 for a temporary pass even though I had paid $120 for the year for parking privileges in the lot near my building.
(Donât get me started on parking at a university).
For the ramp at the U we got two stickers. One had to be pasted on the window but the other could be moved from car to car in a plastic carrier. Woe to anyone who tried to park two cars at the same time though with the same permit number.