Where's the heat exchanger??

[periwinkle]

I have a 3 liter OMC in my 89 Trophy, fresh water cooling. -- I want to winterize so I can still use it. Can't put heat in it because it is on 2nd level dry storage.

I drained the exhaust manifold.

But I'm not positive where the heat exchanger is OR how to drain it. On my old 350 Chev (dif boat) it was located at the top front of engine....

Mechanic said they flush the system out! What are they doing and how do they do that??

Any help appreciated -- You Ifish guys are usually on top of things..

Thanx, Peri :whazzup:

Look on the side off the oil pan.

[boater]

the heat exchanger should have a radiator cap on it just like your other boat had, if you dont see a tank with a radiator cap on it i would go down and drain the engine block.

[periwinkle]

Thanks Boater and Keta. :smile: I do remember seeing a unit with a radiator cap on top, near front (not very big tho) -- I'll check for pit **** and tubes and sea water. There is a 3" diameter 12" long tube near pan. Could that be power steering oil cooler? OMC/Cobra manual doesn't show any of this stuff!!!

If I open block drain won't just anti freeze come out since it is fresh water cooled?

I had checked w/ mechanic at Olympic Boats in Everett (which sold these boats) and the dumba$$ said he didn't know anything about OMC's -- sure wouldn't go there for servicing!!

The 3" diameter tube is your heat exchanger, drain the raw water side and keep the anti freeze in the engine side. Replace the zincs (on the drain plugs) when you put the plugs back in.


#2

[ 11-05-2003, 11:50 AM: Message edited by: Keta ]

[Miss B Haven]

I think Keta is right. The heat exchanger won't have a cap on it. The expansion tank will have a cap to add antifreeze to the "fresh water" side of the system.
A heat exchanger is a closed system on both sides with the raw water cooling hose going in one side from the pump and a hose leading to the manifolds or riser (depending on whether you are a full FW cooled or partial). The FW (antifreeze) side of the heat exchanger has a hose from the engine (hot side) and one leading to the water pump (cool side). So... your heat exchanger should have 4 seperate hoses and inlets/outlets.

PS- you can "winterize" the entire raw water side by dropping the stern drive in an anitfreeze tank and running the engine. It wil lpump the anitfreeze solution through the raw water side and back into the tank thru the exhaust. That's what a lot of the boat shops do. The problem is that that stuff is toxic and when you launch it in the spring you will pump all that antifreeze into the river.
I used RV (non-toxic) antifreeze and the mickey mouse ears hooked to a funnel to do the same thing. Much easier on the enviroment. Draining the heat exchanger and manifolds wil do the same thing. Don't forget to drop the stern drive fully and let it drain as well.

[Miss B Haven]

PS- your heat exchanger should have a pencil zinc in it to prevent galvanic corrosion. If you don't knwo where it is it's pretty safe to assume you haven't replaced it. Should be a small brass hex head plug in the heat exchanger. Pull it and check/replace the zinc. :smile:

[ 11-06-2003, 10:22 AM: Message edited by: Miss B Haven ]