8V92TA coolant in bilge

[FlyNavyAir]

Good afternoon,

1991 Hatteras 52 CMY, 8V92TA, 2200 hours, coolant changed 100 hours prior, oil/filter changed 100 hours prior, uses ~ one gallon DELO 100 40 every 75 hours, little/no smoke on start or run.

Completed a short cruise yesterday. Run time was 2.2 hours at 1100-1850 RPM to home marina. Temp and pressures were normal. After shutdown checks were normal with no fluid noted in bilges.

This morning arrived at boat to clean up the engine room and noted coolant in the port engine bilge. Wet vacuumed approximately 3 gallons of very clean coolant (no oil). I visually verified coolant loss in tank. I looked the engine over from top to bottom. No indication of leak in upper portion. Looking at the diapers under the engine I did not see any coolant stain under the coolant tank cap overflow tube (no bottle installed). Looking aft I noticed coolant stain just aft of the oil pan on the diaper.

I'm thinking a hose under the engine (maybe to the boost cooler) may be leaking but I cannot get a good visual. I'll borrow one of my spouse's mirrors to try to get a better picture tomorrow. It is odd that whatever leaked did so when the engine was cooling off overnight??

I appreciate recommendations on other items to check before my mech arrives.

 

[Captain Ralph]

The after cooler H/E is under the engine under everything. Any external condensation settles here. Also, anything that can soften hoses from the insides (coolant side) settles here also.

It's one of the most neglected components of a DDC TA engine. Ya know there is a zinc down there on the raw water end???

I hoping you will just find the usual bad hose clamp.
Next issue is usually a soft and leaking coolant hose at the clamp.
Rarely have I witnessed this H/E leaking coolant down there but it has happened.

 

[Captain Ralph]

Just remembered, there is a coolant drain pet-cock or drain plug down under there that could be an issue also.
Have fun.

 

[FlyNavyAir]

Thanks Captain Ralph. I'll take a look at both areas you identified. The engine room on the 52 CMY is tight, particularly outboard of the engines. I'll try laying on my side to get a better view.

 

[Steve Mannshardt]

The after cooler H/E is under the engine under everything. Any external condensation settles here. Also, anything that can soften hoses from the insides (coolant side) settles here also. It's one of the most neglected components of a DDC TA engine. Ya know there is a zinc down there on the raw water end???I hoping you will just find the usual bad hose clamp.Next issue is usually a soft and leaking coolant hose at the clamp. Rarely have I witnessed this H/E leaking coolant down there but it has happened.

Have a look at the coolant circulating pump weep hole whole running.

 

[rwaldrop13]

I have the 8v92 series service manual if you need it. It's a PDF, my email rwaldrop13@gmail.com.

 

[FlyNavyAir]

Good morning,

Reporting back my findings. We pressurized the system and located two leaks. Both leaks were on the crossover between the thermostats. The short hoses connecting the rigid pipes had loosened/broken clamps. Tightened/replaced and pressurized again for 4 hours with no leaks. Returned following day and ran engine to 130F without leaks. Checked all hose clamps on both engines.

Thanks again for the recommendations.

 

[drburke]

Good morning,

Reporting back my findings...

Appreciate you for following up to the forum; thanks!

 

[Captain Ralph]

Good morning,

Reporting back my findings. We pressurized the system and located two leaks.

Glad you found the leaks on/near the top.
I do hope you did not get carried aweigh in the pressure. 8-12 PSI max. Also your cap pressure should be 7 -9 psi.

Just a reminder for all, That after-cooler heat exchanger is hard to check but still deserving a look over from time to time.
Post #2.

 

[jim rosenthal]

Glad it was no worse.

 

[newinlet]

Good news glad nothing major