I am looking at a 97 model engine with 150,000 miles and the owner says coolant is getting in the oil, What are the causes of this? Head gasket or something major like a crack?

 

Yes. And also the oil/coolant heat exchanger could have an internal leak. This device is found low on the passenger side of the engine.

 

97's did not have the 53 block issue that I am aware of.

So as mentioned, either the coolant to oil cooler, or most likely a head gasket. However the coolant to oil cooler is an easier thing to check. It is part of the oil filter assembly and it bolts to the block.

I have heard of head gaskets leaking more than the oil cooler thingy, so who knows. KD

 

Think of it as a builder , unless they are willing to show you the rod & crank bearings,
coolant will take the babit off the bearings if its been in the oil for a while .

 

Yes its a builder but I wanna make sure there is no cracked block or anything which i dont think the 5.9 has any issues like that does it?

 

An earlyer post said that yr did not have the 53 block , witch was the block that had issues , I have read about the 53 block , but do not know what yrs.
In order to find cracks you have to take it to a [ good ] machine shop to have it checked for cracks , there are 2-3 processes for doing this .
To save a few buck you could disasemble it yourself , but then you could be at a loss there , becouse an experanced eye can see a lot of things during assbley.
I spouse what your looking for is a way to find out before you buy , but the only thing you can do is look for the 53 casting [ lower drivers side front ]
What are you paying ? cheap enough [ 2,500 used runnig ] get a agreement on
conditional return , after machine shop OKs .
I forgot about your coments on oil/water .
Ask a machine shop for the cost of cores [ block,head,crank ect.] pay that.
The leaks are probubly head gasget / cracked head , a good machine shop can fix a lot of cracks but not all .

 

Ok here is the rest of the story, The guy said he was driving along and smelled antifreeze, He pulled over and opened the hood to find his overflow tank with some gray smime in it, So he pulled the dipstick and it had some slime on it also. He called for a wrecker, he said it was Only started again to drive it into his garage (About 50 feet) From that day on it was not started again. Ok so i bought this engine, It was VERY clean and looked to have been well cared for. It has sat for the last month in his garage. Anyway it is said to have Performance Injectors, A fuel plate, Some kind of boost controller, and he said it was dynoed at 350hp and 900 Foot pounds. He is convinced the Hot rod items were the cause for the damage so he didnt install them on his replacement engine and wanted them gone as well as the engine because it was taking up his gargae space. Anyway its all there including the Turbo and Alternator and I payed (Drum Roll Please) Six Hundred Bucks

So how can I tell if the injectors are Performance? They do look new for sure.