Hi Guys Most of the chats i read about break in are old... I have a stock rebuild 89 TD 2.5 S&S (reman company) rebuilt 10 years ago... Now its in just dropped in my 89 caravan... Ive read various approaches... The seemingly most popular one is drive it hard change oil several times on low mile intervals etc..but it talks about newer engines liking this process, but of coarse he doesnt go into whats considered a newer engine & no date on the article i read lol. The key here is this is a 10 year old rebuild, so im not sure how they did the bore back then.... any ideas? FYI it has 10w 30 dino (not synth) in it now. My mechanic ran it a while & drove it around the block a few times, thats it till now.