Well guys, After all my hard work replacing all the timing components ( tensioners, guides, chains, sprockets) Because of the knock issue I had on this 2003 Navigator 5.4 DOHC I did not even get to drive it a week and my next issue reared its ugly head!!!

Here Is the story>

She developed a misfire...started to idle rough..I suspected a bad cop coil as this was a common issue with my other 2000 Navi 5.4...I just let it slide as it only had a rough idle but ran fine other than that (no hesitation while accelerating) But then it started stumbling while overtaking or climbing a hill then triggered the cel light....Pulled the codes and got the good ol p0308 & p0316 So I thought for sure bad cop coil and before throwing money at a new coil pack, I simply swapped the #8 coil & #7 coil to see if the code followed...Next day triggered cel light again and pulled the same p0308 code?? Hummm?? I knew my plugs where not the culprit because I replaced all 8 when I did the timing kit!! So I whipped out the multi-meter thinking I must have a bad coil connector not firing the coil on #8 right....Well she tested good...Just for the hell of it I pulled the coil and put one of my old plugs on it and cranked her up and #8 was definitely getting good fire!!
So I thought it has to be a bad injector or bad injector connector...Warmed up the trk and pulled all the connectors off the injectors...they all ohm out at 12.6 ohms and then I turned the ignition to on and test the volts from connector on #8 and she is getting 12v signal??? So now I start to get VERY worried as I pull out my compression tester and start to test readings on different cylinders....Well...all cylinders but number #8 read at 180 psi and #8 is reading at 120-125 psi
So then I performed a wet test on #8 and the reading jumped to 150-155
So Im pretty sure my rings in #8 cylinder are shot correct??
So Im just about sick and tired of this thing...But I have put so much money in it at this point I just do not think I have a choice but to pull the engine and maybe put a short block in it??
What do you guys think? Machine shop with old block? bore her out?
Anyone have any clue if going the machine shop route will be more cost effective? vrs short block?? should I re-work the heads while its all out?
Or should I just dump some oil additive in it and drive it to the dealership and see what they would do on a trade in for something else??
I just dont know? I just slammed the dang hood and went to the store and picked up a 12 pack of corona and started popping tops...So pissed right now!!

 

Man, that sucks. As a bandaid approach, you could try to replace the rings on that piston, but it's a tall task. Not sure if #8 can be done in-vehicle, the front ones can if you pull the head and remove the oil pan, then undo the connecting rod and pull the piston out. Inspect the rod bearing, the condition of it is a good indicator of how the rest of the engine is. If it's worn, expect that the rest of them are worn. Replace the rings, pop the piston back in, and secure the connecting rod to the crank again and reassemble the rest. As long as the cylinder walls are not worn, then that should fix the problem for now. But, sad to say, the best approach when facing worn piston rings is to rebuild the engine, or replace it with a new one.

It could also be possible that the rings are fine, but they have rotated in such a way that the open end is in the same place, increasing the leakage past the rings. Eric the Car Guy on Youtube actually has one of those cases in his videos, when he replaced the engine in a Chevy, then inspected the old one. Turned out to be fine, just that the rings had lined up their open ends on the piston which showed low compression.

 

Well after calming down and sleeping on it, I thought I would do a leak down test on that cylinder to verify either rings, intake valve, exhaust valve, head gasket, etc for sure...
I do not have a leak down tester... But.. I improvised and pulled the shrader valve out of my compression tool ( at least I can shoot 100 psi into that cylinder.) I brought that cylinder up to top dead center TDC ( on the compression stroke.)
I verified it was on the compression stroke by putting a balloon on top of my compression tool while it was screwed into that cylinder... then bringing to TDC after seeing balloon blow out....I then hooked up air to the end of my compression hose and

Well guess what??

It instantly started hissing BAD out the exhaust valve!!! Air was coming out the DPFE hose and out the tail pipe...And a LOT...Nothing came out of the oil dip stick tube or the oil fill cap...NOTHING..No bubbles in coolant and nothing out the TB butterfly....I even went threw the process of getting it to TDC again just to make sure I was not on the exhaust stroke!!
Whats throwing me for a loop is why did the wet cylinder test up the psi from 120 to 150??? unless I put to much oil in the cylinder and it help seal up around the exhaust valve??
So at this point I'm thinking its a definite head valve issue particularly with #8 exhaust valves..... I have to pull it off to verify but I was going to have to pull it anyway! I guess the light at the end of this tunnel is I might not have to pull the engine because of a ring issue!!

Funny thing about this is I looked for days and days and days back when I did the timing kit to find ANY videos or info on the 5.4 DOHC 4v engine (Navigator 5.4) and I only found ONE...
If you get a chance go to youtube and type in 2012nugget and scroll down til you find "5.4 Lincoln Navigator cylinder head removal" Part 1 & 2
This guy nailed it right off the bat with the statement "if your having an issue with cylinder #8 or the left bank IT WILL BE YOUR HEAD" And then low and behold I have the same issue!! Guy is a trip to! at 2:10 on the first video this guy cracked me up!!

I have a feeling this is a common issue with these engines...I think I read somewhere that the #8 on these 5.4rs runs hotter than the rest of the cylinders resulting in premature failure...Something about bad cooling jacket placement design in the heads, etc... Although I haven't verified this to be true..yet..( But I will when I pull the head!)
Anyway, I will keep ya posted on how this works out as I get to it!!
And if anyone has any little tidbits of advice to share I'm all ears...Thanks

P.S. Thanks Skauber!! I also have been watching "eric the car guy videos" Since you told me about him... And I found the one with the ring issue you told me about! ( 2007 Chevy Tahoe 5.3 engine replacement pt. 4 ) But it Made me tired just watching him do all that work..

 

Subscribing

 

I have seen that video from 2012nugget. if it wasn't for his video i would never been able to replace my valve cover gaskets. Danyboy if you are going to pull the head please do a step by step on how to . 2012nugget skips that part and i really would like to see just in case i need to do the same if my navigator ever has this problem

 

You got it man! I have never done anything like that before but I Have always wanted to pay it forward for all the help and advise I have gotten here on this site, google, YouTube, etc.

 

Just noticed your E99 F250 on your signature..cool..
My wife's ride is the 03 navi but my Ride is a E99 F350 Lariat Crew cab 7.3 4x4 Power Stroke with 420,000 miles! ( bought it with 62,000 miles on it) only mod it has is my TS 6 position chip...(The 140 HP setting is extreme!) I absolutely LOVE this truck!! Best truck I have ever owned PERIOD! I will never get rid of this beast! They dont make em like this anymore...

 

Well guys I have been crazy busy with work lately..So I haven't had time to mess with the navi...But I will dig back into it soon..I'm curious to see what happened with the #8 exhaust valves..Im really hoping I get lucky and its just a broken valve spring! (I really doubt it though!)
I will keep ya posted...