oil cooler - any warning when/if they fail?

I'm running cool on both engines, around 170 at cruise. The only thing that's been bugging me (and original at 22 years) are the oil coolers.

I will replace both of them proactively but wondering if I need to do that this afternoon or can I get another 75-100 hours out of them?

When they fail, is it typically an overheat condition or do you get raw water and oil mixing?

I guess the big question is will they give me some warning before it's too late?


Bob

Bob, whether you have I/B's, with engine mounted sea water pumps, or out drives with drive pumps, your oil pressure will be greater than the sea water suction/supply.... so yes, there is a concern.
Even if these were installed in the supply side, the oil pressure is still greater than the sea water pressure.
You would no doubt loose oil if one were to fail.
Warning? I doubt it, other than low oil pressure warning systems!

They can be taken apart, examined, rebuilt and pressure tested.

.

My U cooler (OEM) failed after 13 years on the transmission side. I wasn't great about replacing the anode, maybe 4 in its lifetime, but I did flush with fresh water after most every use. I had checked the BW fluid just before a big trip, it was high and red. 80 high speed miles later, the next day, it was low and milky and the first sign was a slipping forward clutch. I replaced the cooler and ultimately had to replace the clutch plates after another year of running. I got tired of the prop turning slowly out of gear. I can tell you that during running, AFT will leave with the exhaust, after shutdown, seawater enters the gear.

They usually don't give much warning. Like Dave noted, if the leak is small and you are diligent about fluid checks, you may notice a low level and the water mixed with the fluid if the leak is small. sometimes, they just open up and the fluid get pumped out with the cooling water and the gear stops transmitting power to the prop - the overheat horn usually goes off if the switch is good.

FWIW, I've got one that is still original....yes, wanna replace it but that budget line keeps getting redirected.

I'll probably have a year old one to sell soon.