Possible blown HG, need help to diagnose.
This is going to be long winded, and i apologize in advance.
I just bought my first diesel recently, '97 standard cab powerstroke w/ZF5. 170,000 miles and had been all stock until the PO, within a year, put a 4" exhaust and a TS 6 position chip on it. I got the truck for an extremely good deal and couldn't pass. He was selling cheap because it had "blown head gaskets". Along with that, it had another issue. It was mixing oil into the coolant, from which he told me the oil cooler had gone bad. He replaced the oil cooler but told me he didn't know if he got it together well enough because he didn't press it back together. His reasoning for determining a blown head gasket was water in the oil. So, knowing i was buying a project, i took it.
I have a buddy who is a diesel mechanic and we did some tests. Come to find out, it did indeed have a cracked injector cup. I went ahead and replaced those and drove it for a weekend. Went to the lake and noticed a decent oil leak coming from the oil cooler. Figured i could make it 2 miles to my home. Got 1/4 mile down the road and she ran out of oil (enough to shut down the injectors) and i immediately shut it down and towed it home. once home, pulled the oil cooler and sure enough it had a broken o-ring. replaced that and now the truck has a slight knock. It runs rough and is hard to start, but i'm kind of assuming its because the injectors still haven't bled all the air from the system after running them out of oil? and through this, i noticed i still am getting water into my oil. I check the dipstick, and there doesn't appear to be any water in the crankcase, but if i pull the valve covers off, there is still the milky sludge everywhere on top of the head and in the valve covers, and the end of my tailpipe has a liquid residue in the bottom of it.
My main questions being, could i still be looking at a blown HG? Even though we had found a bad injector cup and wrote that off at the coolant in oil?
And what might be the source of this newly found knock?
Sorry so long, I'm very new to this diesel stuff and looking for help. Not new to these 90's trucks in general though. Any help is greatly appreciated.