I Ok, now that we've headed down that rabbit hole... Diesels need more attention paid to maintenance. Most people blow the head gaskets due to over tuning. Not saying that is the case in 100% of the cases, but way more than half. When you build up too much pressure in the in the engine, it will find the weakest point (gasket) to escape. Before you buy it, take it to someone you can trust or at least someone who works on Diesels to check it over. This is no guarantee, bit still better than just taking it on faith. When I bought mine I had every fluid drained and replaced. This way, you know everything is fresh. Then change the oil every 5000 miles with T6. I add Archoil 9100 in my oil. Whether you use that or not, still change it! When you change the oil check all of the pther fluids. If they look borderline, change those too. When driving, try not to go above 30psi on the turbo. It can go to 40psi,but like I said above, the more pressure the higher the chance of problems. You occasionally will go above, but if you aren't racing people off the lights it will be rare. Take care of your engine and transmission and they will take care of you. I love my 2008 6.4 and I have had no problems during its 190,000 miles.
Ben and Doreen
Home Away From Home - 2017 PT Crusader 315RST
TV - 2008 F250 Lariat 4X4 6.4 Diesel
42 nights camping in 2015
49 nights so far in 2016 (Still Not Enough!)