550 coolant in oil

[bdog2]

Running the 550 recently noticed I kept having to add coolant/water to radiator. Yesterday figured out where its been going. Engine oil looking milky and then started leaking from the dipstick tube at the base where it goes in the block. So it appears the crankcase and oil pan are filling with coolant. My question is what are all the possibilities that I need to consider is the issue. Cracked block, head gasket, oil cooler, water pump? I rebuilt the oil cooler and water pump last year with new seals and gaskets so I feel a little better about ruling those out but....any insight as always is greatly appreciated! Thanks

[Jim B]

Also, cylinder liner or liner seal failure will let coolant into the oil pan.

[bdog2]

Also, cylinder liner or liner seal failure will let coolant into the oil pan.

So Jim B it sounds like it's time to pull it out and overhaul it. Is that what you would suggest? Thanks

[Jim B]

Likely. You might want to drop the belly pan and oil pan, then use a radiator tester to see if you can spot where the coolant is getting into the oil pan. See if it is coming around the outside of a liner or between the lines and piston. Outside would be a liner seal. Inside liner erosion, head gasket, or cracked head. There could still be an issue with the engine oil cooler. Those are some possibilities.

[LeonardL]

The coolers themselves will develop leaks internally. You can block the coolant lines to see if that stops your leak. Otherwise I would suspect either a liner seal or a head gasket since it is putting a lot of fluid inside the engine. Cracks, unless severe, tend to be less fluid and take longer to appear.

[LeonardL]

You could also in theory pressurize the radiator and remove the oil filter. If the cooler is leaking internally then it should show itself with the filter removed.

[bdog2]

Thanks so much gentlemen for all the advice. Much appreciated. It may be minute before I get to it, but I'll let you know when I find out what the issue is.