Engine warranty scum

Hi, guys. I really need an advice.
I'm owner -operator (07' Freightliner Columbia, DD60, 630 K miles). June 2010 I purchased an extended engine warranty from Detroit Diesel for another 2 years 200 K miles. Got overheating problem in November, so I went to the Freightliner dealership, where they replaced head gasket and I paid $3300 out of pocket, because warranty doesn't cover gaskets, seals etc, but only main engine components.
I drove less than a month and noticed some black spots in the coolant. I came back to the dealer, they took a sample of coolant and said that it is not an oil and it might be some "leftovers" from stuff they using to flush the cooling system. So they flushed the cooling system again.
Last week, coolant turn black and this time it was oil in there. I did "blood test" in Speedco and they found coolant in oil as well. I went to the same dealership and they run some tests and found that ether engine's head or one of the liners letting coolant get to the oil. But they couldn't tell if my so-called "warranty" is going to cover it. Basically they have to take engine apart to check what is the real problem. Now, if liner will have crack in it, it's covered but if its cavitation-erosion damage - it is not covered, because of "poor maintenance" of cooling system and I'm looking at $11000 for an overhaul.
So, its like a gambling now. I don't know if it's even possible to need overhaul with 630 K miles and valid manufacturer's extended warranty. Sounds like cheap scam to me. My wife is pregnant and if it happens to be "not warranty" thing - I'm not ready to pay this kind of money right now. Even if I say OK to start taking engine apart, I have to seat right there and watch them, because I don't know if I can trust them.
Thanks.

 

I didn't even have a paper. It's all in computers now.
I think I just learning the hard way.

 

Thanks for your replays, guys!

I did basic engine overhaul at independent shop in Chicago area. It cost me $8401.96 if not count those $1100 dealership rip me of for, when they did their "famous diagnostic", when time is running at $100 in hour rate while some highly educated mechanic doing researches in your engine. I was smart enough to get a hell out from there with just $1101.51 bill on my ###, because next one would of been around $2500.

And I was smart enough to call mechanic I can trust, before I aloud dealer to take engine apart. He said, that he can guaranteed that liners will have cavitation on them and nobody will fix that engine by warranty and he was exactly right! (It's funny, that some mechanics could make a free diagnostic over the phone and others need hours and thousands of dollars to do it.)

All engine liners was covered with cavitation, but not like that cavity was through the liners, but all over in the metal. And the metal wasn't look old or had kind of "rusty color" - I saw some liners from different high-miles engine and can compare - mine was just regular metal color. I should of take some pictures, but I didn't care too much already.

I asked the shop manager about the real cause of oil-coolant mix in my engine, he said, that most likely it's just the way engine build. The old 12.7-liter DD60 engine could easy do over million miles without an overhaul (which doesn't make enough profit to the manufacturer and dealers, I guess), but these newer 14-liter (the one I have) has an issue, when liners goes down inside engine block, causing coolant in oil. I hardly can imagine physics of this process. I'm not an engineer, just a dumb truck driver. But this is what I been told.

Also, after very first trip from Chicago to Houston and back I replaced 1 injector, because engine was working rough and didn't have power. I was told, that injectors problem is very common in DD if you not replace them with rebuild ones at time of overhaul, but I took a chance and kept the old ones, cause I borrowed money from my dad and didn't have an extra $1800-1900 for all 6 injectors.

So far engine running OK. I already put about 8000 miles with an 6-7.5 mpg, but thinking of replacing all injectors ASAP anyway.

Also I made some visits to the Freightliner $tealership, who sold that warranty and I did several calls to Detroit Diesel. I had small stupid hope to cancel that warranty and prorated it, because I had more than 1 year and over 100 K on it left. Or I was hoping to get just any kind of money back from $2900 I paid for it. I can admit, that people from both Freightliner and DD was very polite and said that they would be more than happy do not give money back. And lucky me, I got that warranty so cheap, because now it cost more than $1000 extra, then I paid for it last June. It made me feel way better.

So, hurry up, guys, get one today!!! ))

P.S. 2 Strider: Thanks for for your curiosity! I was kinda sick of that story and wasn't in the mood to write a continue, but now I did ))