once a year plug change

[dybeepvw]

On my 96" Explorer 4.0L xlt, ohv, 4x4 automatic, the number 3 cylinder has misfire once a year and have to replace that plug at that time; it uses no oil and old plug that comes out is never bad looking at all, and just trying to figure out why that cylinder does that. Explorer runs great until engine starts missing and replace plug and it runs great again. Any thoughts out there?

 

[96eb96]

Seems almost every day another 96 Explorer comes out with this problem. Good to know there are so many around .
It is not the plug. What happens is the head gets a small crack. Then it eventually causes a misfire because of coolant. It is a pattern failure seen over and over again. There are a few ways to verify it, but chances are that is your problem. You can put some compressed air in the cylinder and see if the coolant rises.

I (and others) have remedied this with K-seal. It is not a 100% cure, but it is sure worth a try. It does not work for everyone. I had to run the engine with the plug out for 20 min for the K-seal to work. Holding for many miles now.

Plan B is replacing heads, which is very doable on this truck, and not that expensive. You must buy new heads, the whole job is well under $1000 in parts. This engine is so solid that even at this age with all the miles it is good investment.

On an Arizona rust free truck, I would have picked plan B.

 

[BrooklynBay]

Try a hot plug from NGK.

 

[dybeepvw]

Seems almost every day another 96 Explorer comes out with this problem. Good to know there are so many around .
It is not the plug. What happens is the head gets a small crack. Then it eventually causes a misfire because of coolant. It is a pattern failure seen over and over again. There are a few ways to verify it, but chances are that is your problem. You can put some compressed air in the cylinder and see if the coolant rises.

I (and others) have remedied this with K-seal. It is not a 100% cure, but it is sure worth a try. It does not work for everyone. I had to run the engine with the plug out for 20 min for the K-seal to work. Holding for many miles now.

Plan B is replacing heads, which is very doable on this truck, and not that expensive. You must buy new heads, the whole job is well under $1000 in parts. This engine is so solid that even at this age with all the miles it is good investment.

On an Arizona rust free truck, I would have picked plan B.

Thanks 96eb96, I am in Arizona, my 96' has 185,000 miles but still runs and looks great; where do I get Kseal.

 

[koda2000]

Thanks 96eb96, I am in Arizona, my 96' has 185,000 miles but still runs and looks great; where do I get Kseal.

Most auto parts store stock it. I've also bought it off eBay and saved $2-$3. Good stuff!

 

[rasouth]

Kseal will only work where the coolant flows. If there is a crack between valves Kseal won't work. Have you tried replacing the wires? Mine had a similar problem but it was faulty wires.
The best option would be Plan B... Replace heads and gaskets.

 

[dybeepvw]

Kseal will only work where the coolant flows. If there is a crack between valves Kseal won't work. Have you tried replacing the wires? Mine had a similar problem but it was faulty wires.
The best option would be Plan B... Replace heads and gaskets.

Yes replaced wires also; so must be a crack; but will run a year again now, but I will try the Kseal anyway first. Thanks again.