Water in oil 5.0 stern drive 1985

[lake guy]

I recently purchased an 85 Four Winns 5.0 Stern drive. It has enough water in the oil to make it creamy. I changed the oil and filter twice and running in drive way with hose hooked up still has it. What is my next step? Can these setups be pressure tested? The engine seems to run fine with no outer leaks.

[gonzo]

The obvious places for a water leak are: corroded risers/exhaust manifold, head gasket, intake gasket, cracked heads or block, corroded intake manifold crosover pipe. You can pressure test the motor with a house plumbing kit. Disconnect the hoses going from the thermostat housing to the manifolds and plug them. Pressurize the sistem through the hose coming from the transom shield. The pressure should not drop. If you don't have a kit, you can pressurize it with a garden hose and check the oil level. If it goes up the leak is before the exhaust. With an engine of that age, it is advisable to take the risers off and inspect them anyway.
Good luck

[yipster]

in france 7 years back i had the same, "mayonaise" they called it in the oil. than it were new efi mercs with streamlined exhoust manifolds that were a tad low, after installing a new old look exhoust set-up with risers the leaking valve seats were in waranty.

i like your stuff and think you should consider writing a small book or do articles in a boating magazine, gonzo!

[lake guy]

I heated up the engine and changed the oil and filter twice. I spent a day on the lake with no water in oil. Do you still think I have a problem?

[nevd]

The most reliable way is to take an oil sample (from a hot engine using a sampling system through the filler tube) and have it tested by an oil analysis laboratory. Unless the engine oil runs at high operating temperature (greater than 180 deg F) and does very little short cold runs (eg drive way runs), there will always be some water in the oil as it is a product of combustion and some will drain past the rings particularly when the engine stops.

Having creamy oil is an indication of a lot of water (from memory above 2%) and unless it can be very thoroughly drained (some used oil always remains in dead spots), it would then take a number of oil changes for the water content to decrease to undetectable levels. There is also a paste which is very sensitive to water and it can be wiped onto the oil dip stick - most oil companies can supply this.

Hope this is of some assistance.

nevd

[gonzo]

A couple of oil changes with flush would be a good idea. Oil and filters are relatively inexpensive. If the oil is not getting any water it might have been from long term condensation. When the temperature cools down, the air in the crankcase contracts and outside humid air enters. The humidity eventually condensates into the oil. The crankcase keeps working as a pump with temperature changes.