Hi, I have a 2001 Dodge Ram 1500 that I bought used a couple of years ago. About every 20k miles (120k miles on it now) I get a check engine light and upon diagnosis it’s the 4th cylinder spark plug fouled out, every time. I change the spark plug, but the old ones are always identical in damage. Th…

Here are pics of the spark plug, sorry about the quality. You can see the vertical crack in the porcelain.

Is there something about the location of this specific plug that makes it difficult to install? I’m wondering if the plugs are sustaining some kind of damage during installation that causes them to fail.

I can’t see the crack, is it in the electrode side of the plug, inside the cylinder? That seems to be the case as the 3rd pic is just the inside of the plug. You may have a “hot” spot in that cylinder causing pre-ignition. Do you hear the engine knocking? Check out the location of the knock sens…

I had a similar problem on a Ford Aerostar some years back. The problem was a,hairline crack in the cylinder head that would let in just enough coolant into the cylinder that when it hit the plug, it cracked rhe porcelain around the center electrode. The dealer finally pulled the cylinder head and…

I too suspect thermal shock. However, I recommend that you switch your sparkplug brand. I’ve had a lot of problems with Champion sparkplugs in the past. I won’t use them anymore.

Champion is what many Mopar owners swear by as it is the brand used by the factory.

Besides the more likely ideas above, ignition timing might be involved. Especially if it is too far advanced. Have your shop verify the ignition timing is correct for the rpm range you typically use. Also, check ther vacuum ports, esp those that are situated close to number 4. Make sure there ar…

I tend to agree with thermal shock. Is the EGR system operative? It’s quite possible to have an EGR fault without setting a code; mainly if the passages are clogged. Anti-freeze can also cause it but in the cases I’ve seen the side electrode of the plug usually appears to be bleached white or bone …

Cylinder 4 spark plug keeps blowing

Maintenance/Repairs

the_same_mountainbike June 6, 2016, 2:56am 9

Really? That’s a surprise. My experience with them hasn’t been good.

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Cylinder 4 spark plug keeps blowing

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