Upgrade/mod Suggestions

Hey guys,

So I got my bone stock 2007 Navigator L a few days ago and so far, I’m loving it. Moving out of a 2002 F350 7.3.

anyway, I’m looking for suggestions on what to mod or upgrade. My goal is to keep it mostly stock but do a few things to improve the fuel economy and reliability.

1. Tuner/programmer - something simple to improve fuel mileage

2. Filter - stick with stock or upgrade?

3. Anything that needs to be addressed that is known to cause issues that would effect reliability?

All input appreciated

I have a 2008 Expy. I asked my mechanic the same question and he said to do a “cat-back” exhaust and a high flow air filter. I have researched that a little and apparently the system can be made to have a more throaty sound or kept close to stock quiet. Personally I would go for the quieter version and a NAPA Gold air filter (made by Wix). I’m not sold on K&N.


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Replace your spark plugs before the 100k mile interval so you're starting from a known point.

Get a towing tune from 5 star tuning.

Replace the heater hose on the passenger side before it leaks onto your ignition coils. The Dorman replacement part is an upgrade as it uses a metal T fitting in place of the plastic one that tends to crack.

Stay on top of oil changes (10w30 full synthetic) and the engine will last a long time.

Robert Smith said:

I have a 2008 Expy. I asked my mechanic the same question and he said to do a “cat-back” exhaust and a high flow air filter. I have researched that a little and apparently the system can be made to have a more throaty sound or kept close to stock quiet. Personally I would go for the quieter version and a NAPA Gold air filter (made by Wix). I’m not sold on K&N.


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So as far as the cat-back exhaust systems, did your mechanic say that more for the fuel mileage or known problems/reliability? are the cat's know to plug up?

And for the air filter, that's definitely on my list, but still doing research. Trying to decide whether to upgrade to the cold-air intake or not. Does anyone have any data (power or fuel mileage) on improvements after upgrading to a CAI setup?

He said it was for increased torque and mileage. I was towing a 26’ travel trailer at the time. The only issues I am aware in the 2008’s are exhaust manifolds (I replaced the passenger side), and the infamous phasers and phaser sensors. I replace the drivers side and it wasn’t a bad fix at all. Hopefully someone more knowledgeable can comment on additional problems.


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mjp2 said:

Replace your spark plugs before the 100k mile interval so you're starting from a known point.

Get a towing tune from 5 star tuning.

Replace the heater hose on the passenger side before it leaks onto your ignition coils. The Dorman replacement part is an upgrade as it uses a metal T fitting in place of the plastic one that tends to crack.

Stay on top of oil changes (10w30 full synthetic) and the engine will last a long time.

Click to expand...

Spark plugs is on the list. Does anyone have any suggestions on what type? anyone got a link to the TSB for the replacement procedure that has the ford replacement plug part # since they are know to break? or are there better aftermarket plugs to replace the old plugs with?

On Edit: found the TSB link - http://grufmanbil.se/webshop/mektips/tsb08-07-06.pdf

I did find the Lisle 65600 part # for the extraction tool in-case they do break.

Still researching programmers as well. Looking at SCT, Hypertech and edge but still open to suggestions there too. any benefits to the towing tune if I don't plan on towing anything? Just curious since you specifically mentioned "towing tune".

Happen to have the part number for the Dorman replacement heater hose?

Robert Smith said:

He said it was for increased torque and mileage. I was towing a 26’ travel trailer at the time. The only issues I am aware in the 2008’s are exhaust manifolds (I replaced the passenger side), and the infamous phasers and phaser sensors. I replace the drivers side and it wasn’t a bad fix at all. Hopefully someone more knowledgeable can comment on additional problems.


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Click to expand...

Thanks for the info Robert.

Anyone know if the same issues (exhaust manifold, phasers/sensors) are an issue in the 07's as well?

I forgot about the heater hose. Sorry. However mine was the plastics fittings that feed the hoses. It wasn’t real expensive, my mechanic uses standard shoot rates and it just over $100, including parts.


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So far on my list of initial mods/fixes are:

1. Programmer - still researching which one

2. Replace Spark Plugs - looking into where I can find TSBs and which spark plugs to replace the old ones with. Also going to order extraction tool - Lisle 65600 part # and get some carb cleaner to spray them down good before removing

On Edit, I found the TSB - http://grufmanbil.se/webshop/mektips/tsb08-07-06.pdf
However, it doesn't mention a part number for the new plugs. Not a big deal since I'm assuming the replacements should just the standard 1-piece plugs, but could be wrong. Can anyone confirm?

3. Replace air filter - just going with a stock WIX replacement for now

4. Replace Heater Hose - Dorman 626-540

5. Swap to good Synthetic - is there a specific brand that is a favorite here? I know for my F350 7.3L, almost everyone seemed to use Rotella T6 Synthetic.

Heater hose: Dorman 626-540

As for tuners, contact Five Star Tuning. Their stuff is solid and wakes up the truck with reliable performance. I specified the towing tune because I've found it gives good power without stressing the engine or drivetrain.