Water in my oil

i purchased a 1989 260e mercedes benz for a very low price because there was oil in the water …what are the chances it the block and not the heads

Pull the head(s) and hope. If you are lucky it will be a cracked head or a bad head gasket. It is very hard to tell a cracked block without tearing down the motor for visual inspection.

How long has the car been sitting, and how much water is in the oil?

Maybe, if you’re REALLY lucky, it’s just condensation.

You could pressure test the cooling system and pray that it’s condensation as mcparadise mentions.
Pulling the spark plugs and examining them may reveal something if a head gasket breach is suspected.

If the engine has been running with coolant/water diluted engine oil then the engine is likely on its last legs. Diluted oil will wash out bearings and crank journals, cam lobes and valve train parts, score cylinder walls, etc.

If you gt it for a very low price because of the water in oil issue, the previous owner knew something was seriously wrong. Good luck but I would have passed on this 21 year old car.

your title says there’s water in the oil, and your message says there’s oil in the water. This is important: Which is it? And when you say water, do you mean radiator fluid, or do you mean actual water? That’s also important.

I suspect you have a blown head gasket. If there’s water in the oil, you should not drive it until it’s fixed. Have it towed to the mechanic’s. If there’s oil in the water, drive it straight to the mechanic’s and have it fixed, but at least you save the cost of a tow.

Pull out your wallet. This is going to be expensive.

You’ve said nothing about the car’s history or overall condition. You’ll want to confirm this via pulling the heads or a simple pressure leakdown test, but it sounds like you’re in for a very expensive repair. I’d be hesitant to embark on this project without checking out the rest of the vehicle thoroughly. If you were to spend a lot of money getting the engine repaired or replaced and then discovered you had another serious systems problem like a bad tranny or brake system, you could discover that even your very low price was too high.

My recommendation would be to be sure you know what you’re getting into with the car as a whole before shoveling money into the engine problem.