Back to the first post in a sense..
I've noticed that there is ZERO responses from the CRD crowd...
Aside from the previously mentioned NOT relating to a specific engine.. something to check on the CRD's and then some more things for all buys...
Turbo inlet seal.. EASY to get to, 30 seconds.. check to see what color it is.. if it's orange, you'll want to replace that ASAP!!, they deteriorate over time (too soon) and pieces get sucked into your turbo.. oil then leaks down into your swirl motors causing failures.. CHEAP to fix.. you'll want the black seal. If you have a higher mileage (I'd say over ..75K miles) with this orange seal still, you'll want to have your turbo system checked for oil buildup, as well as the swirl motors.
I would also recommend that you get either a filter or an Elephant hose mod done to lessen the amount of oil returning to your engine and turbo. I did the EHM for about $15 and in about 15 min..
To touch up on some other issues mentioned.. there IS a fix for the center column light issue.. the video posted is a great solution.
the sunroof issue HAS been proven to be more of an issue related to your environment... the drain holes running through the roof can get clogged. If you live in an area, or park in an area (say under a tree) and stuff falls on your car often.. you CAN check your drains often to make sure they are NOT clogged.. you have to remove a few items from the sunroof, but it is MUCH easier to do the preventative care than to repair the damage. I personally have never done any care and have ZERO issues.
Something NOT mentioned that is applicable to ALL GC's 2002? and newer I think.. CABIN AIR FILTERS.. they do NOT come standard on ANY trims... but MANY people put them on.. check to see if you have one and if it is beyond clogged.
Check your air filter.. and if you can, check the OIL filter for signs of debris in your engine on diesels... It's on top for a no mess check.
The fuel filter is a little harder to get to, and the fuel/water separators on diesels as well.. check what has been caught!
If it comes with a tow and/or snow plow package.. see if you can find something to test the wires running to it. You can often check to see if you at least have power with a simple volt/multimeter. and check the condition of the pieces.. the rails used for the snow plow packages often rust pretty early.
Check your struts.. it's a SIMPLE check.. push down HARD on the four corners of the vehicle.. it shouldn't pop back up more than twice MAX... otherwise your struts are going out..
Check to see if the spare tire is THERE!.. make sure you have the key to lower it!
If you have locking lug nuts on the GC, make sure the key is there as well..
(I ran into this issue with a convertible I bought once.. XD)
Check the windshield washers.. the jets could be clogged. or disconnected in the case I had, lol.
If the vehicle sends a code while driving it, don't be afraid to go to an auto parts store ON the test drive and have them read the code(s) and explain possible issues.
For EVERY discrepancy you find, don't be afraid to negotiate the price down..
..the biggest thing I can say though (and you are off to a GREAT start if you are reading this thread).. do your research!.. don't ever buy same day.. look up repair costs and prices for EVERYTHING you find wrong and use it your advantage.
I bought a $30K 08 CRD Overland with 82K miles for $17K.. nit pick the CRAP out of the vehicle!! lol.. it cost me $55 to repair all the things I found wrong... use dealer prices when you negotiate though.. lol