Okay, I REALLY need so sound advice. I have been reading thru the threads and it seems just about everyone here is knowledgeable.

I will be as descriptive as i can. I have a 2004 Navigator with only 56k on it. Been very religious about changing oil every 3-5 k. NEVER had any problems.

Three days ago, I was driving on the highway (75mph) and the low pressure light came on and my truck died. I pulled over and tried to turn it back over, and it started but ran REAL rough. So, not wanting to damage anything, I called the tow and had it flat bedded to the shop. I also want to add, I did NOT hear any clanking or noise like something was broken.

The shop told me I needed new plugs and I should go ahead and replace the coil-overs at the same time (no extra labor) so I did. THEN after that, they told me the truck was running and staying on just fine, but it was running REAL rich, filling the shop with smoke, but not throwing any codes.

They did several “test” to find out what was wrong, and they now say I have 2-3 cylinders with little or no compression. And the say it will be cheaper for me to drop a new block in then to troubleshoot the problem. (by the time book) and want $4,000 to do it. How could it go from diying, running like crap, running fine just rich, to 2-3 dead cylinders.

After looking around on the internet for the whole day, I sure think it could be head gasket or rocker arm perhaps... which I know isn’t $4,000!!!

Any advice?

 

wow that is very strange, which cylinders had little/no compression? Were they all on the same side? Sounds like it could be a head issue.

 

I do not know at this point which ones they are taking about. I told them today that i was going to send the tow over to pick it up on monday and take it to the dealer. (im not really, but i do want a second opinion) I can take the covers off and look at the rockers for free... nothing to loose at this point.

It just seems like they would rather make a easy buck, than to do the right thing.. i could be wrong... but it feels that way.

I was reading that this is one of fords best engines and everyone tells me (even the dealer) that 56 is very young.

He couldnt even offer me a semi-resonable reason why he thought it would just wig out like that. he said "maybe" the t-chain jumped??? but wouldnt that make a crap load of noise??

I have had "arm-chair quarterbacks" say... clogged breather, dry rockers, bent/stuck valve, head gasket, broken valve spring, PVC valve, O2 sensor.... do any of these make sense? I have some knowledge and am willing to investigate on my own before taking it some place to be fixed.

 

It would be rare to lose oil pressure that fast on this engine. But if you did lose pressure the lash adjusters would collapse and allow one or more followers to fall off. There should have been a rattling noise though but you never know. This would give you low compression on those affected cylinders ( if the intakes cannot open you cannot pull air into the cyl to compress). Is it possible that you allowed the oil level to get too low? At 75 mph you are only turning around 2000 rpm but a low oil level at higher speeds could momentarly allow oil starvation/low pressure especially if you are traveling downhill. The smoking the dealer sees could be raw gas from these same cylinders going thru the exhaust and causing smoke. Remove the cam covers and check if the lash adjusters have fallen off. If they have you more than likely will have a bent valve stem. Sometimes you get lucky on that though...Someone told you a broken valve spring. That is also possible and could make complete sense in this situation. A broken valve spring can be hard to detect visually,so look close. Another issue could be hydrolock. It is impossible to generate a fuel hydrolock at sustained speeds. Was it possible that you drove through heavy rain or deep puddles just before this happened? You cannot get enough volume of fuel while driving too cause this but an engine can injest enough water to bend rods while it is running. Fuel hydrolock is usually caused while the vehicle is off when an injector sticks open allowing the cyl to fill with gas. A bent rod will show low compression and allow raw fuel through the exhaust to generate smoke. You mentioned there was no noise involved. Depending on how much a rod bends during hydrock there may be no noise involved as well. This "shop" sounds a little confused on diagnosing the problem. If it were me I would send it to a dealer that has a good reputation. At least they should have experience with this engine. At this point I am only guessing on what your problem could be.....take it too a dealer. Good luck

 

I'd go somewhere else real fast cause those guy's give real mechanic's a bad name. So say they replace the engine only to find out it was a electrical issue.

I bet they don't even have the right compression tester for a 5.4

 

Probably stuck valves. The DOHC engines are pretty bad about that, usually on cylinders 7 and 8. Compression test will show it, but a leakdown test will show it even better. The exhaust valves get stuck in the guides and cause misfires.

 

Should i even bother with taking the valve covers off and taking a look? It seems like it wouldn't hurt, AND if its a follower, lifter,bent steam or spring i could at least see that and maybe do that myself.

Im quite sure the guy i took it to, did not do a tear down. he just ran a few compression test and said "no good". I suspect he had other monetary reasons to not too try and figure it out.

 

You won't really see anything by pulling the valve covers, if you've got a problem with a/an valve(s). A leakdown test will show you for sure, and you don't have to fight the valve covers off to do a leakdown test (you'll kill yourself trying to get the valve covers off that engine, it's practically impossible on the passenger's side without recovering the refrigerant and disconnecting some A/C lines).

 

So you would recommend taking it someplace for a leakdown test. or at least start with that.

 

Yeah, that's what I'd do. Just saying "it has no compression" isn't enough. You need to find out why its lost compression before anything else.

 

I disagree. A leakdown may or may not show a problem. A leakdown will only tell you if the valve face is bent or the seat is broken. A bent valve stem or follower off will still allow the valve to seal against the valve seat and you will show a good leakdown. A broken spring can also allow a good leakdown if the valve didn't drop enough to make contact with the piston dome and bend. In this case when you pressurize the chamber the valve can be forced against the seat and make a sufficent seal. You will have to remove the cam covers and visually look for a problem. Thanks

 

With the questions this guy is asking, and assuming his experience, I think it's not a good idea for him to pull the valve covers on this engine given the difficulty of getting them off with the engine in the truck...

Besides, you start with the least invasive tests and go from there. If leakdown hasn't been checked, that's what needs to be done next.

 

Okay,

the truck will be back at my house by tuesday. I will make sure to ask him exactly which numbers he thinks are acting up and then post that here before i spend any money.

I just really want to be 100% sure that replacing the whole block is the best way to go and not just the best way for him to go...

it seems like, from reading around, that it could be a $2,000 fix instead of the $4,000 quick fix he wanted to do.

Like i said, when i called them, even the dealer said that was a weird thing to happen and that the engine is very young.

Also, where can i get a manufacture manual for this engine. I have a friend that can do the leakdown test for me but he wants to know the exact specs that he said the haynes book probably wont have.

 

Sorry i havent followed up, i had guest in town, and the shop took a bit longer than they thought to get the truck back to me.

I was told it is the #7 and 8 that have low/no compression.

The truck fires up with no effort, but i can tell it is sick. The RPM's stay in normal range (around 1k) and it does move in both forward and reverse. The pedal is not as responsive as it normally is, and i have a pretty wicked rattle from the muffler / tail pipe assembly.

ALSO: i was told from a long time Cadilac mech, that the Service Director at my dealer has the abilty to repair it under warranty even though it is 6k past BUT still under the 4 years.

(history: i have purchased my last 3 new cars from the same dealer)

Q1) does that still sound like a $4,000 job

Q2) does anyone know how i approch him (the SD) about maybe getting him to do this?

 

Yeah, it'll need a cylinder head on that side.

And considering that you've bought three cars from that dealer, an "after warranty assistance" claim should be a given. Ford allows up to two of these claims after you're out of warranty. Sometimes they'll foot the whole bill, sometimes they'll split it with you.

I'd ask the service manager of your dealership for after warranty assistance, seeing as how you've been a good customer in the past. Or you could call Ford Customer Service and explain to them what's going on, they may be able to help.