Look for RUST before you buy.
This thread is in Diesel Discussion; but has many good pictures of what to look for and run away from.
Who has the most rust and still drives

I am posting this link here because of several E-mails from gasoline vehicle buyers asking what should have been (PPI) Pre Purchase Inspection questions.

You may enjoy this general automotive theory link. http://www.innerauto.com/

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

https://www.boldegoist.com/