I have:
1999 Class A Motor-home on a
1998 F-53 Chassy,
V-10 with
120,000 miles.

AFAIK - plugs (and wires and tune-up electronics) have never been touched (had it since 34k miles). In fact, to my knowledge, nothing has ever been done to the engine other than changing the fuel filter and very religious routine 3000 mile oil changes. Have gone through 3 trannys though!

Lately, if driving in very wet weather (something I try to avoid) engine really loses power with skipping, hesitation and missing. In dry conditions, engine runs strong and smooth with perhaps a slight decrease in MPG recently (from 8.7 down to maybe 8.3 mpg).

So - I feel like it's about time to do a full tune-up but given what I've read about the heads and threads on this year V-10, changing the plugs has me scared. Any opinions on:
* Given the problems on these older heads, is it even advisable to attempt to remove the plugs?
* If yes, precautions or prep I should do prior to attempting removal (spray them with PB Busters & wait a day)?
* Again, if yes, any secret tips on replacement procedures?
* Worst case scenario if I choose to not R&R 120000 mile plugs? I ask this after reading of the worst case scenario of the heads being screwed up by spitting out plugs.

* Suggestions as to recommendations as to what I should do to complete engine tune-up with or without plug change?

Sorry for this perhaps seeming like a no-brainer but this MH and engine has been so trouble free and given such great service that I have been loath to make any changes. If not for the wet weather behavior, I'd simply stick to the status-quo and drive on.

Thanks in advance,
Steve

 

Look in the Excursion Tech folder, it has a V10 plug change thread. We didn't have any problems on our 2000 V10. Sounds like you might need new spark plug boots also.

 

Sounds like you are where I was prior to changing the plugs. Take your time and be patient. Use anti-seize on the threads, die-electric grease on the boots and might as well replace the boots and springs while your at it. This really should have been done prior to 100k, dont think mine was when I bought it with 126k from the second owner. Stick with Motorcraft parts. Not sure of your location but you can use either rock-auto, horizonpartsguy.com or tousley ford for good prices on all of these parts.

In the thread below check out a couple solutions for the water issue which may be part of your misfiring issues. Next time I will go with the O-rings on each boot.

https://www.ford-trucks.com/forums/1...s-the-fix.html

 

Oh geeze----one more thread were the urban myths have scared the bejesus out of a Modular Motor new owner.

Quite simply stated there is NOT a huge or epidemic-level problem with our motors and spark plugs. Yes it does happen and its not a joy when it does but statistically the rate of occurrence is pretty much insignificant.

What you will find is plugs that have been improperly installed or left in too long which creates problems when they're removed. Sadly if damage has already been done (but not yet blown a plug out) there's not a lot to be done reversing that damage. If there's an upside its that if they're all still intact that says they're likely to stay that way.

After blowing out the plug wells with compressed air attempt to remove each plug, testing how much force is required to turn them out. If severe resistance is met use PB Blaster, Kroil or any other great penetrating fluid---spray or dribble some into the plug well and let it work an hour or so.

If that doesn't do the trick twist them out 1/8 or less of a turn, squirt fluid in wait a few moments then turn them back in---do this repeatedly but apply the fluid now and again to prevent hydro-locking the motor.

Once the plugs are out I use a thin layer of nickel-based anti-seize on nothing but Motor Craft plugs, torque them to 21-23 ft/lbs. No more---that's more than enough.

A dab of dielectric grease inside the wiring harness connector, just inside the boot's upper and lower openings then install them. Following this procedure I've had no issues at all.

COP's tend to last a long long time however if one does go bad do yourself a favor and use only Motor Craft or the NAPA versions. There are cheaper COP's but time after time we see they either quickly fail completely or begin throwing misfire codes. Because I hate doing a job more than once I use the best parts known----it saves money and time in the long run.

HTH

 

Also, correct me if I'm wrong, but isn't the 99 mostly safe from the disintegrating plugs? I thought that was the later ones, ours just had the issue of plugs spitting out of the block. If that's the case, removal and replacing the plugs should be pretty straightforward. In fact, you're probably better off that they've never been changed, as you know the PO didn't torque the heck out of them. Allows you to put fresh in, torque'd to proper levels (12 ft-lb, right?) with antisieze, and you're good to go for another 120k!

(Please correct any of the previous statements. I'm a new owner of a 126k mile '99 that needs OE plugs changed out too, so I'm watching threads like these with bated breath).

 

you shouldn't have any troubles removing the plugs on yours, the issue is lack of threads in the head, which is the reason for the "light" torque specs, I like JWA's spec of 21-23 ft/lbs , as 12 sure doesn't feel like its tight enough, but thats your choice

 

Change the plugs and boots with motorcraft parts. Make sure the engine is "overnight" cold and don't over tighten them. They are easy to change compared to a lot of other engines. You will be happy with the end result given the symptoms you describe.

 

Thanks for ALL the great advice and thoughts!

I am seeing a number of models for plugs for this engine and not sure which are the ones I should purchase. Is my best bet to remove the old ones and get the exact same plugs?

 

Use the Motor Craft or Autolite plugs spec'd for your engine---nothing else.

While some may disagree that the ECM or COP doesn't know or care what plug they're firing time after time here we've seen examples where another brand has caused performance issues.

 

Hummmmmmmmmmmmmmmmmmmm.....
Wet Weather....
Check for any water getting into the air filter system.