Random Fouling on Cylinder #4

[Supersnizzz]

I have had this issue for such a long time with my Explorer where I will drive it for around 4 months and then I begin to have a misfire on cylinder 4. As far as I can tell, it seems to be that I have a very slow oil leak in that cylinder. I think it may be either a messed up ring or a leaky valve stem seal. What do you all think ?

 

[je5]

Could be either one. If it is an OHV I would put air pressure in the cylinder and replace the valve seals. You could also use a non-fouler on that spark-plug.

 

[Supersnizzz]

Could be either one. If it is an OHV I would put air pressure in the cylinder and replace the valve seals. You could also use a non-fouler on that spark-plug.

Yeah it is an OHV. What exactly do you mean by a non-fouler?

 

[je5]

Crown that fits on end of sparkplug.

 

[Supersnizzz]

Thanks for the second opinion. I'll look into that. I'll blow out and replace the seal this weekend as I had planned.

 

[checkedout]

Also could be a cracked head as they are known for that especially around #4.

 

[Supersnizzz]

Also could be a cracked head as they are known for that especially around #4.

I will take a look at it when I start pulling out stuff to work on it. I hope that is not it though. I dont have any funny colors from my exhaust or in my coolant. The coolant level hasnt dropped considerably over the past year it has been happening, and it never gets worse. Do you still think that a cracked head is a serious possibility? Thanks for your opinion.

 

[checkedout]

I will take a look at it when I start pulling out stuff to work on it. I hope that is not it though. I dont have any funny colors from my exhaust or in my coolant. The coolant level hasnt dropped considerably over the past year it has been happening, and it never gets worse. Do you still think that a cracked head is a serious possibility? Thanks for your opinion.

I do. It happened to mine. I didn't have any coolant in the crankcase or any oil in the coolant, no smoke of any kind from the exhaust. Every couple / few months for years, I would have to add a quart or two of coolant. Then it started to get a little more often. One day while changing plugs I noticed #4 plug had a slight green tint to it. A compression check showed that chamber a little lower then the rest.

 

[Supersnizzz]

OK then thanks. I'l look into that.