Last time I took my boat out, I got a couple of gallons of water out of the bilge when I pulled the garboard plug. I had taken water over the bow a couple of times and though I thought it was excessive, did not give it too much thought. I winterized my boat a couple of days ago and since then, I have noticed a slow dribble of antifreeze coming out of the garboard drain. I checked all the hose clamps and blue plugs and they are all tight. I think it's coming from the fuel cooler. At the slow rate it's coming out, I think I could live with it indefinitely since it appears that the only way to replace the fuel cooler is to remove the engine. Any thoughts?

FYI: the water flow on my engine is as follows: outdrive--> raw water pump--> power steering oil cooler--> fuel cooler--> oil cooler--> thermostat housing--> engine block--> thermostat housing--> exhaust manifolds--> outdrive

Where is it leaking from the fuel cooler? I doubt it ate through the side.

I have no idea if it's really broken or not, I cannot see anything down there, it's encased in a plastic box with the fuel pump and is mounted under the engine mount, next to the oil pan on the port side. It's a terrible place to put an elctro-mechanical device, such as a fuel pump, IMO... I only think it's leaking because I can remove the hose that connects to it (through the oil cooler) at the thermostat housing, pour anti-freeze in, wait awhile, and the anti-freeze level in the hose drops while puddles of anti-freeze form in the bilge. I cannot see any leaks and it's the only device in the coolant path that I cannot see. The oil cooler, raw water punmp and power steering cooler are "easy" to inspect. My gut says it had minor freeze damage over one of the colder nights we had recently. It's the lowest point in the whole cooling system.

My system was designed the same way and mounted in the same spot. The design, if I remember correctly is a "tube in tube" where the fuel sits around the outside of the inner tube, coolant flows through the inner tube. Make sense? I'll try to dig the cooler up tonight and see if there is any plugs or anything that would leak.

BTW, I owe you lunch and your socket back. This week's out, you around next?

this is what mine looks like:


part#8 is the cooler. Seems to be a fuel tube within a coolant tube.

I should be around next week. Might have to got to NJ though... Email me.

Dave, I've got the same set up and pray that I never lose the fuel pump!! There is a drain plug on the bottom that could be your culprit. Otherwise, can you get a mechanic's mirror anywhere near it?

T-squared, I hoped it was just the plug, but I could not feel any moisture on it. Good idea with the mirror. I think I'll buy a better mirror, mine won't reach all the way down there so I never even bothered. There's a new Advance Auto parts store down the street from my house, I bet they have the mirror I need...

ok, if everything is in that plastic box, where ya gonna look?

To see if the coolant is coming out of the plastic box. If it is, then I know it's the fuel cooler.

When I asked I was thinking of specifics, whether a hose, a clamp, a crack--

sucks that engineers don't give a second thought to such things...

That doesn't look like alot of fun. Good luck

The cooler ends protrude from the plastic box, so I can see the hose clamps on both ends. I just figured if the coolant is indeed leaking from the plastic box, it can only be one thing, a failed cooler.

I might try to pressurize the system a little, from the oil cooler back to the raw water pump. While I don't expect a perfect seal between the inlet and outlet of the raw water pump, it is a positive displacement style pump and any leakage through the pump should be minimal and the lost coolant from that leakage would flow to the outdrive, not the bilge. Maybe the 3-5 PSI will make the bilge leak easy to spot...

I almost hate to mention this, but if the fuel cooler is damaged, don't you run the risk of a fuel leak? Not a good thing to happen in the bilge...

The fuel line runs inside the pipe-shaped cooler. Ice would be much more likely to burst the thin, soft, copper outer shell of the cooler, rather than do any damage to the thicker and smaller diameter fuel line, which is built much like a brake line.

Update?