We bought a new 1995 2430 6.5 Diesel Trek, and drove it for 137,000 miles. As I have documented in Trek Tracks, the injection pump was troublesome, and the engine had a tendency to easily overheat. In mountain driving, I had to limit speed based on the aftermarket temperature gauge (the GM dashboard temperature gauge read 20 - 30 degrees too low). Driven lightly, some owners have had very good luck with the 6.5 engine. We towed a 5000 lb car trailer and, in retrospect, this was too heavy a load for the engine.
In 2009, we bought a used 1999 Trek with the Chevrolet 454 V8. This has significantly more power, and gas mileage is only about 1MPG less than the diesel.
If you are at all serious about buying the Trek, I highly suggest researching the Trek Tracks website.
Originally Posted by Nick-B
The 6.5 diesel (and its 6.2 predecessor) was a decent and economical engine in the GM pickups. Not near the bulletproof quality of the Cummins or Powerstroke but no worse than the GM gas engines. Depending on the size & weight of the Safari you might find it to be lacking power for the weight it needs to pull. The only issues I'm aware of are the Stanadyne injections pumps had a high failure rate when the diesel fuel got reformulated to low sulfur. Replacement pumps were upgraded to accomodate.