Dodge Durango Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
Ever see plugs like this from the newer Hemi? 97K miles, original plugs. Only one cylinder, the other plugs were clean, wondering if this is a common symptom.

I don’t see any smoke from the exhaust, oil is clean, still ran okay was getting an intermittent mis fire of course but I expect that.

seems to be a bit of carbon, very hard and not wet. Some of the porcelain chipped off as well when I picked off some carbon.

I’m thinking maybe a weak coil or maybe improper burn from a bad injector?

0D9CEBBC-7FD6-45FE-B4E8-F1D01EBA1F93.jpeg
3D6D6755-044C-4477-B804-DEBC15E1DE5D.jpeg
7442AAB2-5EE4-4878-83B7-C773C7B18C91.jpeg
 

·
Premium Member
Joined
·
2,435 Posts
SD:
This looks like some oil getting into the cylinder. What year Durango is this, and which cylinder? You might try moving that coil to another cylinder, and see if the misfire goes with it. That is certainly not common or normal on a properly running engine.

Don
 

·
Super Moderator
Joined
·
12,620 Posts
the PCV system spits up oil that mostly gets dumped into one cylinder, though this seems like a lot..
 

·
Registered
Joined
·
14 Posts
Discussion Starter #4
Well it does have 100K miles on the original plugs so I am not sure if this happened over a week, month or the last 5 years. They were definitely the original plugs for sure. I am going to clean it up, check the PCV and maybe swap the coil and check again in 10K Miles.

Run some seafoam through it to clean things up. I scoped the cylinder and while I see some oil on the top of the piston, it is not really bad at all on the top of the piston. I was expecting to see another cylinder similar to this but the others were clean.
 

·
Registered
Joined
·
4,076 Posts
Yikes!!!
No, not normal from my experience.
I just changed the plugs in my '14 out at 98K...and they all looked like your 3rd picture..no oil on the treads, perfect light brown and the gap was the same on all 16 plugs.
Never seen that on my '06 Hemi either and it has 230,000.

On the first picture, it looks like the spark plug seal on the valve cover is leaking...how old it this Hemi?
Maybe it only saw short trips and as tomK mentioned maybe from the PCV system?
If true, makes a solid case for a catch-can.
 

·
Administrator
Joined
·
8,007 Posts
It could also be a bad valve seal.
 

·
Registered
Joined
·
4,076 Posts
I would think you'd see blue smoke at start up with a bad valve seal...but maybe the cats are covering it up?
Still seems too low mileage for valve seals to be bad.
Maybe a compression test on the cylinder just to confirm things are sealing properly.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #9
We cleaned up the PCV, ran seafoam to clean up the cylinder. The PCV was dirty but still functional, we cleaned it up anyway and also swapped the coil with another cylinder. I spoke to an engineer at FCA and he also indicated that the valve seal material should last in excess of 250K Miles. We are going to run a tank full with new plugs and inspect it again and include a compression test.

The build up is definitely abnormal, too excessive for normal wear, I am thinking maybe a bad oil ring or leak in the head gasket. I don't know how long it has been going on, being only 89K miles on the engine, I don't know if this happened in the last 1K miles or has been ongoing over the 89K. An inspection in a week or so should be an indication. All other cylinders were perfectly clean, not a single spec of carbon or oil so I am very concerned.

I don't see any smoke on initial startup which would indicate a valve seal or ongoing smoke which would indicate a larger leak such as a gasket or ring but I suspect that something internally is not happy. Maybe the CAT is masking the smoke but it seems to run smooth and doesn't feel like your average misfire so it may very well be compression related, just enough loss to cause the misfire code but not a full misfire if that makes sense, I've seen this happen on some other vehicles.

Well see in a week or so, appreciate your feedback though.
 

·
Administrator
Joined
·
8,007 Posts
I know when my Prius started using oil, at the rate of 1 qt. per thousand miles, I had no smoke whatsoever. No leaks, just burned it.
 

·
Registered
Joined
·
4,076 Posts
Head gasket would make more sense being one cylinder than rings. Engine might have been overheated at some point before you acquired it.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #12
Head gasket would make more sense being one cylinder than rings. Engine might have been overheated at some point before you acquired it.
The vehicle was very well maintained, 1 owner, with only 89K Miles I don't expect any plug to look like this. We'll run the new plugs for a week and inspect to see what we have. I would expect the plug to be a bit wet though, it was dried and hard, usually oil burning would show some wetness so maybe it is carbon build up from too much fuel? I've never seen an injector stick open or apply more fuel that usual, when an injector fails, it usually just stops working and you can usually hear/feel a hard misfire.

The oil filter was cut open and clean, no debris, the coolant was good but flushed and checked for oil contamination and it was very clean. When a head gasket goes there is usually a more severe sign but maybe this is the'one-off' where just a little oil is leaking. The engine is not using any oil between changes either, never been low.

Scratching my head at this one but going to give it a full tank run and inspect to see what we got. I just can't tell if the problem happened over the whole 89K miles or if it just started in the last 1K so a short run will tell me something.
 

·
Registered
Joined
·
11 Posts
Injectors can definitely fail and stick open. Can't comment on your specific problem, but am interested to see what they look like after a week. Maybe I missed it, but which cylinder is it?
 

·
Registered
Joined
·
4,076 Posts
Agree...would be surprised to see head gasket, typically coolant is what you loose and plug would be clean.
Crazy, hopefully a one off issue.
 
1 - 16 of 16 Posts
Top