Ford Spark Plug Problems

What Problems Exist?

2 valve engines may have spark plug threads strip. This can also cause the spark plug to blow out of the engine while it is running.

3 valve engines have a unique spark plug design. The spark plugs can become seized in the head and break into two pieces.

What 2 valve engines are affected?

2 valve engines include the following 4.6L V8, 5.4L V8, 6.8L V10

The following 2 valve engines are affected 1997-2004 Ford Mustang 1997-2008 Ford Crown Victoria 1997-2004 Ford Expedition 1997-2008 Ford E-Series 1998-2004 F53 Motorhome Chassis 1998-2004 Ford F-Series 2001-2005 Ford Excursion 2002-2006 Ford Explorer and Mercury Mountanier 1997-2007 Lincoln Town Car 1997-2008 Mercury Grand Marquis

What 3 valve engines are affected?

3 valve engines include the following 4.6L V8, 5.4L V8 VIN 5, and 6.8L V10

The following 3 valve engines are affected 2005-2008 Ford Mustang 2004-2008 Ford F-150 2005-2008 Ford Expedition, F-Super Duty 2006-2008 Ford Explorer F-53 Motorhome Chassis 2007-2008 Ford Explorer Sport Trac 2005-2008 Lincoln Navigator 2006-2008 Lincoln Mark LT 2006-2008 Mercury Mountaineer

2 Valve Spark Plugs

Torque

Threads may strip during spark plug removal or installation.

Plugs may also blow out during normal operation.

Spark plug torque is critical! Spec is only 7-15 ft.-lbs.

Make sure to look up the exact spec for your application and use a proper torque wrench.

If the spark plugs are not properly torqued, they WILL cause problems in the future.

There are only 4 threads in the aluminum cylinder head, the following slide is a picture of a head off of the vehicle.

What happens when the threads are stripped?

If the plug blew out, a new coil on plug assembly will be necessary. Ford sells a repair kit, and there are many other available in the aftermarket to attempt cylinder head repair in vehicle. Advise the customer that the repair will not work 100% of the time and the

head may need to be further repaired in the future. Follow the instructions of your tool closely, dont skip any steps.

The spark plug may bounce around, and cause damage to fuel injectors, engine harnesses, the hood, etc., be sure to perform a thorough inspection of the damage.

The following slides will illustrate what a broken ignition coil looks like, and the plug that broke it.

What happens when the in-vehicle repair doesnt work? Sometimes the thread insert does not hold. It may last a year, month,

day or minutes. When this happens the head will have to come off and be repaired from the inside.

It is easiest to remove the motor to service the cylinder heads in most vehicles.

The following slides show an actual case study of a failed repair.

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03 Ford F-250 5.4 2V

Runs Rough

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Using Scan Tools

OE and aftermarket scan tools have powerful tests built into them

The Ford IDS is a great example of this

The power balance test shows us what cylinder is misfiring

The relative compression test checks the mechanical integrity of the engine

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Analysis

The power balance quickly identifies that we have a misfire on cylinder 2

Next we will test compression using the tool

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Diagnosis

Quickly and efficiently we find out that this vehicle has a mechanical issue.

By the time the technician actually opened the hood of this vehicle he knew he has a mechanical misfire on cylinder 2.

After compression and leak down testing he finds a tuliped intake valve.

Diagnosis Continued

The intake valve became tuliped because the vehicle ran lean.

The engine ran lean because the thread insert used to repair a blown out plug became loose, causing the plug to not fire.

The engine ran very lean causing the valve to get hot and tulip.

The following slides show the spark plug and insert removed from the engine. Notice how melted the electrode of the plug is.

The Fix?

The engine had to be removed, and disassembled so the head could be sent to the machine shop.

The machine shop installed a new valve. The also installed a thread insert from the inside.

3 Valve Spark Plugs

Removal

Plugs may break into two pieces during removal.

The plug is uniquely designed because a regular spark plug could not fit into the limited head space because of such large valves.

Ford TSB #08-7-6 addresses spark plug removal. *Note* this is Fords procedure using their tools. Aftermarket procedures may vary and tools will vary.

The spark plug hex is 9/16, so a special socket must be used.

Removal Continued

Some technicians in the field report that doing a top-engine cleaning prior to spark plug removal helps. This is because carbon buildup at the tip of the plug is what causes them to break, not corrosion.

Some technicians try to break the plugs loose a little bit and soak carb cleaner or penetrating oil down the spark plug tube.

Some technicians are using cordless impact wrenches to remove the spark plugs with success.

Matts Removal Method

I do not try and break the plugs loose and use penetrating oil. The many times I have tried this I found that the plug would break within the first 1/8 turn anyways.

I do not use any top engine cleaners, but Im not against it.

I use a 3/8 OTC spark plug socket. P/N 6900

I use a cordless impact gun. The cordless works much better than a pneumatic wrench, because there are less intense impacts and more of them.

If the plug breaks using this method, in my opinion there was nothing you could do to prevent it from breaking.

What happens when the spark plug breaks off?

You will end up with a piece of spark plug that looks like this.

The rest of the spark plug will have to be extracted using a special tool.

Lisle Special Tool P/N 65600

Extraction

The Lisle extractor is the preferred tool to the aftermarket.

This tool will push the porcelain of the spark plug tip in and allow an extractor screw to remove the rest of the spark plug.

Problems and Solutions

If trouble occurs during spark plug removal, make sure the porcelain pusher tool was fully installed and fully engaged.

The extractor screw is only good for about 4-8 extractions. After that it becomes too worn out. The extractor screw is available separately from most tool dealers.

If all else fails, engine removal is sometimes necessary. Make sure your customer understands this before repairs begin.

How does the customer get billed?

Ford recommends actual time.

Average book time to replace spark plugs is 2-4 hours, depending on vehicle and engine. This is if none of them break.

Average extraction can take 15-60 minutes if all goes well.

Good rule of thumb, bill your 2-4 hours. Then bill .5 to 1 hour extra for each broken plug. If the engine has to be removed, more time will be needed.

Also be sure to bill $10 - $20 tool fee for each extraction. This is because the tool will wear out and have to be replaced. This should be a shop supplied tool, not technician supplied!

After a technician becomes proficient at removal, money can be made!

Installation

Torque is critical! When you look up the spec, you will find that the torque spec can be double some 2 valve motors.

Apply anti-seize to the ground electrode. Nickel anti-seize is a must. It may cost a lot of money, but can be billed to the customer. Permatex and Locktite P/N 77124

Ford Motorcraft P/N XL-2

Use only Motorcraft Plugs There are known problems with Autolite plugs falling apart.

Champion has a one piece problem solving plug. This plug is only available in 1 heat range and has been known to cause misfires.

Spark Plug Intervals

Ford originally recommended that the spark plugs be changed every 100,000 miles. This is far too long for this style of plug.

Most dealers are now recommending 30,000 mile service intervals.

If you remove an ignition COP and see paint on top of the spark plug, the plugs are OE.

So how common are all of these problems?