Dying (?) 1999 RV
 

We've had our 1999 E450 Born Free for 6 years. Recently had coil issues, replaced with cheapies, then paid to have all new Motorcraft coils put in. Still got cyl. 4 misfire. Couldn't remove plug. Went to a mechanic who scoped it and found plastic blocking the plug wrench.

He changed the plug, but also noted it was oily and fouled. Checked cylinder pressure and got 70 psi.

Now I understand it's a downhill situation, and the heads need to be pulled etc. Could anybody give me ideas? Cost to do heads. Swap for a used motor. Sell it and get a newer one?

We LIVE in this and need dependability. I've modified the chassis with all kinds of technology, and am somewhat concerned about gettting a used RV and being in the same situation. Plug was not grey at all. Just oily and had grit on the threads.

I'm WAY past the point of doing this myself. Ideas? Cost? We're in California but are willing to drive for a trustworthy mechanic.

Thanks!!

You don't list your mileage and while the compression test result should be taken in context with the other cylinders also being tested (both wet and dry) having just the heads reman'd isn't always the best idea. With higher mileage the short block will have wear issues so adding refreshed heads stresses those components to the point you may be creating bigger problems then you have currently.

A used engine without any reliable or verifiable maintenance record is a big gamble IMHO---what to do if it too has issues? I'd have the remaining cylinders tested and make a decision based on that---something in the realm of a complete reman'd engine with a national warranty if you travel extensively.

HTH

Sorry for the lack of info. I bought the RV with 45000 miles and it now has 126K on it. The problem with a remanufacured engine idea is cost vs the value of the entire vehicle. Installed I'm guessing $5000 and the RV is worth approx. $20K without the engine issue.
I'm also confused about testing of remaining cylinders. How will that affect what I do?

I would do a quick check I've used for years first. Get the motor warmed up to operating temp and block the wheels. This may be a little harder because it's a van front end but remove the oil fill cap and have someone apply the brakes and with it in gear step on the gas while standing to the side and see if any oil vapor comes out of the hole, if it does compression is getting past the rings and the motor needs to be replaced if not do a complete compresion test and you may get by just having the heads replaced with rebuilt ones or rebuilding yours.

Denny

Did the mechanic run a compression test on just #4 cylinder?
I would get the whole bank compression checked, especially #4 again, before deciding anything big.
Questions for the community - is a cylinder with 70 psi considered a misfire?
Will it fire at 70 psi?
How is a "misfire" actually detected?
A fouled plug could caused by a number of things.
I can see a broken valve spring or stripped plug threads, but a burned valve or bad rings at 126k, seems odd.

I just replaced a 5.4 with barely 145K miles due excessively low oil pressure---holding barely 8 PSI hot idle. Its rare for any Modular motor to fail so soon yet its entirely possible. Without further testing of this particular engine naturally its too early to know if its a definite candidate for engine replacement.

As for valve vs cost of repairs---how valuable is the RV portion of this vehicle to you? Can you afford to dump this one as is and get something newer or different? Or is it a good camper and worth the anticipated engine replacement cost? (A V10 would be more than $5k---my 5.4 Ford reman'd engine cost me close to $3K out the door, labor and a few minor other small parts pushes the price to about $4,500.)

RV's are tough to gauge if they're worth repairing or selling off as is to someone willing to take on the necessary repairs.

Sorry I can be more helpful.

I've read about the 5.4l oil pump backing plates having issues.
Did you find out why the pressure was low - bad ring, bearing spun, cracked tensioner?
I'm going to start a timing chain replacement on our 5.4l with 175k soon and am replacing the oil pump while in there.
Never had the oil pressure light come on, so that's good, I think it's set for 7psi.
I will be adding a digital gauge, too, the stock gauge panel warning light is almost useless.

Correct on the stock "oil pressure gauge" & sending unit---they're both pretty much worthless and yes the sending until will open at about 7 PSI. During idling or coming to a stop the "gauge" would drop to zero and warning light and tone would alert me. I installed an actual gauge at the sending unit location for the most accurate reading. When at full operating temperature increasing the RPM's by 100 the OP would shoot up to 65 PSI or so.

I even added a concoction of Rotella 10W-40 oil and one quart of Lucas Oil Stabilizer---no real change in OP at hot idle. FWIW spec is 25-30 at hot idle.

I installed an Auto Meter DC stepper motor OP gauge---pricey for sure but nothing compared to the replacement engine. :)

I didn't bother to look into why the OP was so low, simply assumed it was a failing oil pump or severe wear of the bearing journals---whichever it was just didn't matter, some damage had probably already been done by the previous fleet owner. As that van will become my main work vehicle I need high reliability---I'll be able to recoup my money completely in 4-6 months after its in full time service.

Tanksalot
 

If you got 70psi on the suspect cylinder then you’re heading the right direction. That’s way too low. 70psi is definitely a failing cylinder. No doubt.
But as mentioned by other people here: it’s odd to test just one cylinder. Flip side:

Have them start by removing the valve cover and checking the followers, lifters, springs, etc. maybe you’ll get lucky and find a small problem here.

I recently went through a low compression issue on #5 for my 2007 E350 V10 and it turned out to be a pinhole in the cylinder head in the combustion chamber. I bought a used head and had it rebuilt at a local engine rebuilder. About $325.
Plus 3-4hrs to remove the bad head from my van.
Please gaskets, plus 2-4hrs to install the good head.

full disclosure: as we dug into mine , I was naturally drawn to dig in further.
-might as well do the other head while we’re in this deep
-might as well do the timing set while we’re in there
-might as well change the bad motor mount
-might as well do the water pump ... (Woops: won’t come out... scratch that)
- might as well change all the lifters since this one feels funny
-might as well change all the followers since they touch the valves and lifters.

After much (MUCH!) deliberation i decided to not to get into the short block. And my engine had 330,000 miles, so it was a tough decision.
With yours being barely over 100,000 miles- I confidently suggest you don’t dig any deeper than necessary.

And for the record: we removed both heads with the engine still in the van. Don’t let your mechanic tell you it can’t be done.

I haven't changed a water pump on a Triton, what did you mean it won't come out?

We removed the bolts and it was still stuck in there. I sprayed some penetrating oil- no help. Rubber hammer- no help.

Thanks for all the responses! We looked at another RV and I realized I'd have to make all the improvements that I've made all over again. Although I love do-it-yourself, my body keeps contradicting me. Reluctantly, I HAVE to pay $$$$ to get this resolved. We need an RV that we can depend on for at least 5 years. I've been quoted $2000 for just redoing the heads and $10,000 for a rebuilt motor installed. The $2000 quote would get it done in October.

We're committed to keeping this RV, since it suits us perfectly. With a new plug on #4, the codes I get are Cylinder 4 misfire and "System too lean bank 1". The System too lean bank 1 error comes and goes.

The questions I'm facing are:
1. Am I risking the entire motor by having the heads (only) done? I've been told that the new heads will over-stress the block and I'll be back to needing an engine. One garage told me they refuse to do just the heads for that reason.
2. Although I'm in Santa Clara, I believe I can get the work done for less elsewhere. But where? We have ZERO plans until this is resolved, but silicon valley is not the best place to get reasonable prices.
3. I need the peace of mind that whoever does the work CARES about quality and longevity. I've thought about talking to rebuilt motor dealers and asking for their best customers out West.
4. Finding a trustworthy, knowledgeable garage who will work on an RV motor (10 1/2 ft high) is a challenge. Suggestions within 1500 miles of San Francisco??

Thanks in advance for your feedback!

Before you make any decisions you need a complete dry and wet compression test on all the cylinders and I would also recommend a bore scope on the low one or any other low ones. You have to know what you are dealing with, I say have a scope done because even if a cylinder fails the wet test doesn't mean its a valve problem because it could be a cylinder wall problem, I've had this happen to me because a piston pin walked out and cut a grove in the cylinder wall, it acted just like yours and I was sure a valve job would fix it.

I just looked at your other post and with 125k mileage it's a no brainer to install a remanufactured motor if it was mine it would be a Ford crate motor.

Denny

I strongly agree with everything this guy in the first half. Strongly.

However; 125,000 miles is very low and it would be unwise to replace the whole engine.

That pricing seems crazy high.

Your question/concern #1 is nonsense. That logic doesn’t make sense at all. How could a refreshed head stress the block? That’s foolishness.

Keep in mind im the guy who had both heads done and reinstalled on my 330,000 mile v10 engine. And it’s running strong today. It is used in my business by an employee running 600-1,000 miles per week.