5700 mile update
 

2008 Expy EL Eddie Bauer purchased 11/10/08 with 272 miles.Just hit 5700 miles today and not ONE trip to the dealer for anything other than it's first oil change last weekend. Averaging 14-16 MPG in town, 19-21 on the highway. Plenty of room for everything we need with the 3rd row seat folded down. Question, is it safe to wash under the hood without worry of coil pack issues that I've read about?Thank for any info.

I have not read any coil pack issues for the expys. What is the concern as I would like to wash the engine too.

Here's my concern on this... I am obsessed with clean engines. I spray down with simple green about 4-5x per year and then hit it with the pressure washer.

This was my routine practive with our 2000 Expedition. Then I had a coil pack failure around 90k miles. The service guy told me that they were all pretty rusty. Then at 95k I had the plugs changed. There was alot of rust around all the plug holes but they came out okay. With around 500 miles on the new plugs, one of them blew the threads out. It had to be tapped and was about a $1200 fix on top of the $800 plug change.

The blown plug issue seemed fairly common for the 5.4 for a few years so I don't know if the washing and rust made the problem worse or not, but I'm a little more careful with the 07 Expedition just in case. I don't hit the area of the coil packs/plugs with the pressure washer and I run the engine during and about 30 minutes after so that it completely dries.

Makes me feel better about it anyways, and I don't have to live with a dirty motor.

Coil packs go bad and I don't think washing the engine unless you really flooded it harmed them. The moisture left by washing the motor would be evaporated the first time you drove it any distance. Thats my 2 cents.

Washing is ok as long as you dont go overboard. Spray everything down and if you do use a pressure washer, be very careful about dousing the coil pack area with heavy pressure. A quick pass with the washer won't harm anything but don't get crazy with it. The coild pack and the connectors are designed to be "weather-pak" type and will resist moisture intrusion, but rain fall and water thrown up by the tires/suspension is not really under pressure. Heavy handing with a pressure washer can easily force water inside the connections and cause problems.

From what I recall, and I could be wrong, but the 5.4 V8 and the V10 from a couple of years ago were spitting out spark plugs due to improper torque when they were replaced. The heads had very little depth in the spark plug thread area and replacing the plugs without proper torque caused them to either work their way out of the hole or strip out the thread. Either case making a nice little indentation in your hood! I saw a couple of them come into a dealer with the plug stuck right into the underside of the hood. I'm not sure when Ford changed the depth of the threaded portion of the head, but I haven't heard the horror stories lately so it seems as though that problem may have been rectified.

My plug that blew loose was jackhammering the coil pack riding on top of it into the air intake.