Photos: Kevin Wilson
Project Box Puller
Part I: What to Expect When Buying a Used Diesel
If anything positive has come from the latest economic downturn in the United States, it’s that Americans are relearning the value of the dollar. According to recent surveys, Americans are putting away more money now than in the past 20 years, and people are looking more closely at monthly spending than ever before. While the credit crunch has put the hurt on new truck sales, more and more diesel enthusiasts are fixing up and updating the vehicle they current own rather than create huge debt by buying new.
The flip side of the coin is that the used diesel truck market is stronger than ever. Since a lot of diesel enthusiasts would rather not deal with new DPF-equipped trucks, especially since they intend to modify them to suit their purposes anyway, many folks are buying used diesel trucks. The recent diesel fuel price spikes front loaded the used market with plenty of quality used diesels so you can get just about anything you want at a reasonable price.
Case in point. We ran into a gentleman in Arizona who is a part-time racer and was tired of pulling his racer with a well-worn small-block gas truck. After scanning the classified and web sites, he ran across a truck and trailer combination that fit his budget. The truck is an ’01 Ford F-350 extended cab dually equipped with a 7.3L Power Stroke and 6-speed manual transmission. The setup used to be a Castrol Racing/John Force car hauler that racked up 215,000 miles. The trailer is a 28-foot goose-neck Featherlite. He bought the whole setup for under $15,000. Considering the truck itself is worth well over $10,000 he got a good deal to say the least.
Now the fun begins; assessing what you have and modifying it for not only longevity and reliability, but for more power, performance and fuel economy as well. Over the next few issues, we’ll be upgrading this high-miler Ford with a whole host of aftermarket goodies while showing you some tricks specifically for the 7.3L. We’ll also bolt-on a few extra goodies to get Project Box Hauler in tip top shape to be a reliable daily driver and serious towing workhorse.
Step 1: Diagnostics
OK, you’ve found yourself a great deal on a used diesel, but where do you start your project buildup? The first step is to critically assess what you have and perform some routine maintenance. We took our dually to the Ford specialists at Strictly Diesel in Scottsdale, Ariz., where owner Nate Brekken went over the truck with a fine tooth comb. What you don’t notice during your initial drive-before-you-buy-it road test might be revealed later during a more thorough exam.
Scan tool in hand, Nate plugged into the high-miler hauler and pulled up a couple of “soft codes” (no check engine light), which included misfires on cylinders #3 and #8. Without further inspection, (ie, a compression check) the educated guestimate was that a couple of injectors have given up the ghost. Not enough to notice when we were driving it, but a rough idle should have been the first clue the Power Stroke wasn’t hitting on all eight. Nate also found exhaust leaks on the up pipes which he said is very common on 7.3-liters, as well as minor scuffing on the turbo blades from poor air filtration. Yes, the air filter element was packed with dirt.
A road test revealed low boost pressure, (12 versus 16 psi) which Nate said could be a combination of the misfiring cylinders and the dirty air filter element inside the stock housing which was also missing part of its cover. He also noticed the values for the injection control regulator, which controls the fuel injectors, was slightly low. A visual inspection also revealed cracked front brake rotors, which is common on a vehicle that has seen a lot of tow duties.
Step II: Fluid and Filter Changes
OK, so we know the high-miler hauler needs a little work. Next up, a look at the vehicle’s fluids, they can tell you a lot. An oil change was a no brainer since the oil was black and slightly smelled like diesel fuel. We refilled it with 14-quarts of Shell Rotella T 15W-40 and changed the oil filter. Nate recommends a factory filter since he’s seen drivability issues in the past with 7.3s using cheap oil filters. Since the truck’s fuel injectors are actuated by oil pressure, his theory made sense.
On to the transmission. The six-speed manual in this truck made a lot of “growling” noises under low-speed loads. We figured a fluid change, and an additive might help quiet the gearbox down. Not quite. Surprisingly the automatic trans fluid in the gearbox was not bad and only slightly smoked when we pulled it out. We replaced it with six quarts of Royal Purple’s Synchromax and added a tube of MCG Multi-Gear additive for good measure. It shifts easier, but still makes noise. Nate told us that many of the 6-speed boxes do, even new.
The worst news of all, other than dead cylinders in the engine, which may or may not be injectors or bad valves, was the rear end. When Nate pulled the fill plug on the Dana 80, the magnetic plug was covered with what looked like a mix of silver silicone sealer and metal shavings. Ironically, the rear end is not noisy, so maybe, for a 200,000+ mile truck, the plug magnet was doing its job and caught all the bad stuff. The rear end fluid was in OK, shape. On our next visit, we’ll pull the inspection cover and flush the differential, inspect the gears and lash, and refill it and add a cool looking, large capacity diff cover from PML.
Last, and certainly not least, Nate pulled the fuel filter, which was extremely dirty, and replaced it with a new factory Ford part, again for reliability.
Next month, we’ll finish the rear end inspection and fluid change, install the new PML Dana 80 diff cover and tackle the exhaust leaks with a new bellows-style up pipe kit from Strictly Diesel. We’ll also add the standard diesel upgrades, an aftermarket intake and exhaust before digging deeper into the injector issue. Stay tuned.
Shell Oil Company