I originally posted this in a different thread but was advised I might have better luck here. I'm looking at 97 F250 HD 7.3 diesel crew cab short bed 4x4 with about 255k miles. As far as cosmetics, trucks in good shape except for minor wear. No problem there. I'm more concerned with pricey mechanical issues (whether current or future). Seller has already done some upgrades:
Both Front Leaf springs (Triple springs vs the original dual springs) and hangers/hardware
New wheels
New Tires-Toyo Open Country (295/75R16)
New shocks
Alignment
Brakes, front and rear (Complete on the rear, drums, shoes, wheel cylinders, springs, adjusters, etc)
Headlights
Tailgate
Two Batteries
Alternator
Glow plugs-Harness Gasket, glow plugs, etc.
Belt
Idler pulley
Both front door panels
Both rear window motors
Locking hubs
Carrier Bearing
Shift arm and bushing
Other than obvious leaks and burning fluid smells, anything else I should be cautious of when checking it out. Any advice from you kind folks is much appreciated. I'm willing to put some money into it, but not wanting to go bankrupt in the process lol. It's something I'm looking to keep for as long as possible. Just not as familiar with ford diesels as I am chevy.

 

Correct me if I'm wrong, but I think you ought to be in the OBS 7.3 forum. (1994.5 - 1997). I'm not offended, I'm just sayin'. There are some, mostly, minor differences on the mechanical side. Also a crew cab F250 OBS truck, I've never seen one, honestly I didn't think they existed in anything smaller than a 1 ton. Pictures!!

As far as stuff to check, they're mostly the same. Make sure it doesn't have crazy blow by. Pull the oil fill cap and make sure it's not chugging smoke like a coal train. (I've never found clarification as to whethera or not you need to clamp off the CCV line when you do this, maybe someone else will know and chime in)

Check the turbo for side-to-side and axial play.

If you can check out ball joints and u-joints. Those can add a hefty bill right off the bat. Ask me how I know! (Or don't, I don't want to relive that )

If you're dead set on entering the powerstroke world, buy an OBD II bluetooth adapter off amazon. $25- $100. And download Forscan for your laptop (free) and buy torque pro for your phone ($5 last I checked).

Forscan will delve deeper into the computer to read codes than any parts store scanner for way less money. It will pull every code on the truck from every module. It's also really good at reading live data and giving good data resolution from your sensors but it's kind of clunky to use. But the ability to pull codes makes it well worth bringing to a test drive.

Torque pro is really good at letting you see sensor data like it was gauges on your phone. You'll want this hooked up for a test drive. You'll need to go in settings and add the ford extended PID list. Then you'll want to add a bunch of gauges.

For sure on a test drive I would want at minimum: Boost (ford specific), Distance traveled since codes cleared, Fuel Injector Pulse Width, Injection Control Pressure, Injector Pressure Regulator Duty Cycle, and Voltage

Boost will tell you if the turbo is reaching it's full potential when you put the pedal to the floor for a slightly extended time. I don't know what you should see here on an unloaded OBS truck.

DTSCC will tell you if the seller cleared the codes right before you got there.

FIPW can tell many stories. But I would start by watching to make sure it doesn't go past 3.6 ms (will display as 3600 with standard settings) on a WOT run. If it does the truck is tuned, and it's not a good one. I would walk away at this point, because I'm me, but frankly 10 years ago any tuned 7.3 probably would have seen FIPW cross the 3.6 ms line.

Injection Control Pressure: Will display as HPOP on the gauge. Given that a 97' has a 15* HPOP vs the 17* on late 99's and after. I don't know for sure how much pressure you should see here. I'm guessing if it can hold 2600 psi on a WOT run the HPOP is in good shape. But you'll want to check in the OBS forums for that info.

Injector Pressure Regulator Duty Cycle: This will tell you how hard the truck is trying to work to build pressure. I'll have to look back and find what you should be seeing here but I'm short on time tonight so hopefully tomorrow morning. (I'll edit it in here)

Voltage Should see 14.4V

There are a billion other things I wish I'd checked before I bought my truck but some of it really isn't realistic. This list is pretty realistic, and if it's missing anything I hope others chime in.

Also check out the tech folder in the stickies in the top of the forum. Last I checked it had a how to buy a 7.3 topic. And it has every common and most uncommon problems (with fixes) you could run into as an owner. It's a lot of reading, but you could be the most prepared new owner ever! Skim it and you'll have a pretty good idea what you're getting into.

Also if you want to melt the windshield off of Dirtymaxes and Cummins with your big blue oval. 7.3 isn't the platform for you, its really expensive to make big power. But if you want a good, reliable, hard working truck; you're looking in the right place.