I just bought a 93 F350 Crew Cab 7.3 Diesel with 288k miles. What are some common issues I should look out for and what kinds of maintenance is important for these diesel engines? What kind of issues arise around 288k miles? How long do these engines typically last? I am new to diesel.

 

6.9/7.3 IDI Diesel New Owner FAQ

 

The FAQ is great, and should tell you just about everything you need to know about common maintenance and issues.

288k miles, you might need new injectors and a new IP. They're supposed to be replaced approximately every 100k. The IP and injectors lose pressure over time, so even though the truck may be running smooth, you could end up with 2/3 or even half of your available power/economy, depending on how worn out they are.

Change the oil, maintain SCAs (see the FAQ). That's about it.

300k is pretty common. 400k, even 500k is do-able but it'll probably be burning some serious oil if it isn't already. When they get old and tired, they just keep on going but burn massive amounts of oil. If you can keep up with the oil consumption, your truck might not ever die.

 

Thank you both.

What is an IP?

What causes the engine to consume so much oil as it gets older?

 

Oil consumption is, I think, hit or miss. Mine, for example, has 326k now, and uses almost no oil (and that's with Rotella -- which is widely rumored to cause high oil consumption). "Almost no" means I have to add maybe one or two quarts between oil changes, which for me is 5000 miles.

 

IP is fuel injection pump, the high pressure pump.

And I would guess the oil consumption is the result of worn out cylinder rings and/or cavitation of the cylinder walls. These engines are high compression (21.5:1) and that can force oil past the rings, especially when they're worn.

 

Bingo. Your IP is mounted on top of the intake manifold all the way forward. Where you add engine oil is the cover for the IP's driven gear.

And yes, oil consumption is a result of worn rings. Diesels have higher compression and generally last longer than gas engines, so burning oil is more evident in old diesel engines than old gas engines.

Oil consumption is not related to cavitation. Cavitation is a phenomenon that occurs between the water jacket and the cylinder. A cavitated block will have water in the cylinder and combustion gases in the coolant, but the oil system will remain intact.

See the FAQ for more details about cavitation. Your truck probably hasn't cavitated all the way through, but you need to be aware of the problem and maintain your coolant correctly to avoid it.

 

I have a 1990 7.3 that has 377k miles on it, and never uses more than 3 quarts of oil in between changes (3-4k).

And my '85 E350 6.9 cargo van, witch has 420k miles, uses 2 quarts of oil every 400-500 miles. It was a company plumbing van before me, and has been for it's entire life before my ownership 2 years ago, so I can imagine the abuse it took...