Spark Plug Manufacturers Defect

What material plugs (iridium , platinum . . . ) are you using?

What is your application?

Normal warranties cover material and workmanship and excludes abuse.

Describe what you mean by improper stamping.

It might be time to change that keyboard because the shift and several of the punctuation keys would appear to be not working correctly, resulting in very little of the meaning coming through. Please re-post.

if it stayed threaded , how did a failure like the porcelein cracking cause an engine and trans to fail?

It is a pity there isn't a "good question" button.

Have a GA instead.

I'm having problems with this, too.

Seems that even if it ate the porcelain, it would only wreck that cylinder.

I have changed spark plugs for the last 48 years. I have seen the porcelain come loose from spark plugs on occasion. I have seen many old plugs leak between shell and porcelain. I have seen the porcelain come all the way out of a few plugs. I have twisted the hex right off of a spark plug. But none of them ever damaged the cylinder head.

1) Cylinder pressure is always stronger on the power stroke, than any other time.

2) The shell is rolled over on the outside of the plug, making the porcelain able to be pushed away from the cylinder head, not sucked into it.

Please explain how the engine was damaged from a part of the spark plug becoming separated from the threaded shell? Thank you, and welcome to the site.

In my opinion, the first thing you need to do is a failure analysis to determine what really happened to your vehicle. Your conclusion points to a spark plug defect. Based on your evidence, I would not rule out some type of hydraulic lock. This means that fluid entered the combustion chamber and the plug encountered hydraulic pressure far in excess of the gas pressure it should have been exposed to under normal combustion conditions. This pressure could have been responsible for all kinds of destruction, including your spark plug damage. I suggest you check for one or more broken pistons and connecting rods. Get to the bottom of the problem before you begin legal action.

Good advice.....that is also a possible area of failure, more likely than a faulty plug from a top manufacturer (if it was a top one!).

Its a great reason to drive diesels to my mind ( please don't bother to tell me anything bad about glow plugs, there is only one really good make of them!!

I have NEVER had one go bad either.....

By the way, the single main cause of glow and spark plug failure is over tightening!!!

Many install without a torque wrench.....

Ok, I'll ask. What brand of glow plugs are better than the rest?

I had an 85 Ford truck with the 6.9 diesel they used from International Harvester. I had advanced the injector timing for better acceleration, and had frequent glow plug failures. About every 18 months I would find failed glow plugs that had swollen and were hard to remove at times. I was told the cause was the timing change. I would welcome your opinion.

You cannot expect to change timing from the engine manufacturers spec and to completely get away with it!! You were lucky that it was only an easily replaceable part, though not cheap here in Germany....I expect the same where you are.

You must either stay standard with an engine setup or accept the consequences. Doing that on a petrol/gas engine could cause overheating and possible serious engine damage.

Though using Beru glow plugs means that I have driven well over a million miles (rough guess! Maybe more!), in 6 different diesel cars with them. They were installed from new in all the new cars, so none of these ever needed replacement.

Which means that I have actually only ever bought one set in almost 30 years, not really much of a test, more just belief....

I did replace the original glow plugs (no idea what name they were) in a Mitsubishi Galant I bought secondhand in '87/?), that I (probably falsely) believed was a slow starter.....as even though the glow plug timing indicator went from red to green (to indicate that the plugs were hot enough to start), the engine needed another 5 seconds before it would start easily.

I saw this as an indication of the need for a new set of plugs.....amateur night!!!

Even though all the plugs glowed beautifully under test.

Much later, a mechanic friend of mine did its emission tests in one cold January day, he picked the car up early (minus 20°C night, not run since the day before). I asked him later what he thought about the starting, he said it was the best starting diesel engine he had ever driven......DUUUHHHH!

I probably never needed to replace them....whatever they were.....

My thoughts are today that the glow plug timing circuit was faulty, maybe the outside temperature sensor was defective.....though I sold that car many years ago.....with over 400,000 Kms on the clock, it was still starting really well AFTER I understood what my mechanic friend said....though that was my first every car diesel engine.......

A simple extra 5 seconds extra and it was an immediate starter......

You live and learn!!!

That car was bought with a defective cylinder head (the early ones had a manufacturing defect), which I replaced, drove 150,000 kms, then my wife filled it with petrol/gas and did a fast autobahn drive, so I bought another cylinder head.....

It ran for another 70,000 kms before being sold.....also a good hot test of the then best synthetic oil that I was using!!!! Only the head was damaged (not even the glow plugs had a problem with that either!!!! I re-used everything, cam, glow plugs and valves in the new head!!!

My present car has nearly 200,000 kms with the first set of Beru still in from new in 2006....

I found an interesting pdf here from Bosch:-

Bosch Glow Plug Manual

See pages 6 & 7 for example:- The second possible cause of failure is incorrect engine timing.....'nuff said?

If I can be of any further help.....just ask.

um, simple question but what does your insurance company say? If they will cover it isn't it going to be a hell of a lot simpler and cheaper than taking a large company with their own lawyers to court?

Depending on where you are, your legal costs (not to mention wasted time) could easily exceed the value of your vehicle even if you win!

Spark plugs use a bonding agent to adhere the porcelain to the metal as well as the rolled lip, this helps create a total seal between the component's. Sometimes I need to separate these component's to make adapters for connecting high pressure air hoses to the sparkplug threaded hole for doing leak down test (I know they can be purchased). I have found some that are bonded so well that attempting to separate the ceramic ends up destroying the metal body.

Do you have both parts of the sparkplugs that are in question? is there any sign of a rolled lip in the metal body? is there any sign of the bonding agent on either part? is there any sign of mechanical damage to either part? can you submit pictures?

If and when the porcelain is ejected this removes the load from that cylinder, what forces could have caused additional failure?