What is this under/behind Capt's seat, next to storage, had a leak w/yellow fluid

YeOldeStonecat

Active Member
Jun 10, 2018
332
Waterford, CT, boat in Deep River, CT
Boat Info
'97 300 DA "Me-Shell"
Engines
Twin 5.7 V-Drive
So after giving my engine bilge it's first hosing and wash down, I fired up the engines to ensure electronics were good and..they'd start, and get them warm so things would dry off better.

Having my rear lounge seats out, I could see where there was a small leak of what looked like yellow antifreeze. It didn't smell like it..seemed more watery, but..it was definitely bright yellow fluid, not very oily. See picture one..it was running down where the yellow line is drawn in and running aft.

I'm like "Where the heck is that coming from?" I removed the cup holder to the right of that storage area and...see second pic. Looks like a blower fan unit and I see two hoses there. I could not see a leak there..but couldn't get hand in there either to feel under a hose. To service this, how to heck to get to it?

Leak1.jpg
Leak2.jpg
 
Is it possible you have some kind of cockpit heater that runs on engine heat? Those sure look like coolant hoses. My only guess on access would be from under your helm seat if there is a panel there. Looks like a fun one!
 
Yes I do have a little blower fan to the right of/down from my steering wheel, with a "heat" option. Basically blows onto my right knee...but much like a dashboard vent on a car, you can aim it. Only other thing I can think of is the mid cabin (what I call the dog house)...our daughters little room down there, I have to look again but I think there's 1x vent but I assumed that was fed with ducting going to the main cabin unit under our v-berth bed.
 
Looking at the second picture, it sure does look like there's a trail of fluid coming from the heat exchanger or the hoses/connections.
 
my 330 has the same option. if you follow the hoses coming starboard motor you will see they run up to that compartment. you will see your heat exchanger level start to go down

Saverio
 
I would check your hose connections and make sure they are tight and that the hose is not rotten there and leaking. You can also take the plastic wrap off and see if the hose has a leak, but put the protective wrap back in place when finished. My big question is why is it yellow don't know of many antifreeze brands if any that are yellow.
 
It is your cockpit heater, it only heats the cockpit, may have an extra vent near windshield that acts like a defroster...
 
OK, some updates from this past weekends wrenching research. Managed to find a way to get to it, that fold out storage cabinet behind the Captains bench, the "wall" on the right side is carpet covered, has an angle bracket holding the bottom. But that wasn't enough to remove it! There's a wood screw hidden behind the right latch component to "latch" the swing out hatch to this storage. Need to remove the plastic "Catch" via 2x sdrews, to reveal the head of the hidden wood screw underneath.

So what I noticed....the "small radiator" that is the heat exchanger only seems to leak if you turn on the heat for the helm blower/defroster. You can hear a solenoid click..if you turn on the heat. Must be a little valve/pump in there towards the right. I fired up the engines after doing my oil change..and let them run for a while. And I turned on the fan. No drips. I then turned on the "heater" switch....and within 5 minutes...could see the yellow drip..same spots as prior pictures. Hoses seem dry, so drip must be coming out from that little heater core/heat exchanger box, from the back side.

Added note..when I noticed those drips over the past 2 weeks..that rocker switch by the console fan..was on "heat" mode by accident. I'm tall and lanky, and when I'm at the helm, my right knee often bumps that heat rocker switch..turning it "on".

We took a 2 hour cruise yesterday, up to speed, etc...and no drips noted after return to dock. So if I don't run the heater on the console air vents at the helm...no leak! Can downgrade this repair from critical to "when I can get to it!"

ConsoleBlower1.jpg
ConsoleBlower2.jpg
HelmSeatStorage - Copy.jpg
 
You need to make sure you winterize correctly, I just did mine. I pull the hoses off the engine and force Antifreeze through the system, with the switch in “Hot” to open the valve. You would be surprised how much water is in those lines.

I did have a leak some time ago, There is a small radiator in the Grey Box that I took to the local radiator shop and had them weld up the leak and pressure check. No Problems since then…
 
I don't... but the hoses attached to the Circulating Water Pump on the Front of the Engine. Should be two hoses, you should be able to track them forward to the Heater / Defroster.
 
Did you ever fix it? Where did you buy. Mine was disconnected when I purchased it so I am assuming it leaks.

I'll take pics of the unit I removed. It just put a butt ends in the hoses...so the hose "in" and hose "out" just connected to each other. I don't run her in the winter so I don't need the heater at the windshield. Took the little radiator/fax "box" out...it's in my garage.
 
When I bought my boat the heater under the helm seat leaked (my boat has raw water cooling) so I had it bypassed, but all the hoses are still there to reconnect if and when I decide to pull the heater core out to fix it. I think its a PIA to get at the heater core and I don't really need heat at the helm so I put it off. @YeOldeStonecat How hard was it to remove the unit on your 300?
 
Its not that hard to remove in a 330. I pulled and took to a radiator shop and they welded and pressure checked. Have not have an issue since.
 
When I bought my boat the heater under the helm seat leaked (my boat has raw water cooling) so I had it bypassed, but all the hoses are still there to reconnect if and when I decide to pull the heater core out to fix it. I think its a PIA to get at the heater core and I don't really need heat at the helm so I put it off. @YeOldeStonecat How hard was it to remove the unit on your 300?

Half hour or so....give or take a few beers. :)
When you flip open the life jacket storage locker behind the helm seat, there is a carpet covered wall/partition on the right side. Has several 90* brackets that screw in to hold it...once you remove that little partition wall, you'll see the little "radiator/fan" unit back there. 2x hoses going to it from/to the starboard engine....hose clamps to pull 'em, and a little wire harness for the power and fan switch. Unit itself is about 1 foot by...8" or so...I still owe you that picture, will be home later today and grab it since I do want to get the part number and see if flounder pounder has 'em.
 
Finally got pics...although likely too late. I notice there is no label on the one I removed from my boat, so I have no part number yet to go by if I decide to replace it. The small openings in the last 2 pics had a small copper pipe sticking out, one of those was the source of the leak where it attached to the heater core (basically a small radiator)
Heater1.jpg
Heater2.jpg
Heater3.jpg
Heater4.jpg
Heater5.jpg
 
Thanks. Its smaller than I expected. A good project for whenever we can actually get to the boats this spring.
 

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