Yanmar 6lp oil cooler end cap leak

[socalmike]

Was 75 miles offshore when my bilge alarm sounded briefly. (Small pucker). Took a look in the bilge and saw more water that I would have liked. Went to idle and searched all thu hulls for leaks. All good. Went back into gear and noticed as soon as any pressure was put on the raw water side the stern cap on the oil cooler was spraying water. Slowed down or 2900 rpm and had a steady pee all the way back to port. Stopped every 15 miles and pumped the bilge. Under no load, no leak. Only leaks when pressure is added to the raw water side via rpm.

I am trying to figure out if I need to remove the after cooler to get the oil cooler off. I have order new seals for the end caps.

Any help greatly appreciated.

Mike

[Halcyon]

Sounds like raw water pressure might be up. Are you hoses tight under load?

A circulating rydlime flush will clear the coolers and lower the pressure.

[catalina_mike]

One of two things or both. Restriction down stream or in the cooler it self or gasket failure. Pull the cooler and inspect it internaly then new gaskets.

[Carl]

If your are typically 75 miles offshore, sounds like its time to remove all the coolers, have them sonically cleaned, re-sealed, painted, pressure tested and then re-installed.

[socalmike]

Turns out the end cap on the oil cooler had a crack in it. Did the rydlyme flush and replaced the seals and end cap. Back in business.

[tdsull]

Mike, I have a leak in the end cap of my oil cooler.. I have ordered new gaskets etc.

When you replaced yours did you clean (can you inspect??) the inside casing where the oil travels.
I am at 20 years now and not sure if I should be considering a whole new unit.

I am going to pull it off on Saturday and play around with removing the copper seawater tubes.

[RobS]

All you will see with the end cap removed is the seawater tube stack.

[tdsull]

Right. I talked to a radiator shop today, they will clean the seawater and oil sides.
I will supply the gaskets and o-rings and they will reassemble and pressure test. I might replace the oil lines too.
Thanks.

[tdsull]

I ended up finding the stern end cap had a crack too. Barnacle buster, new gaskets, kerosene flush of oil lines and new paint.