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TURSTY 06-11-2013 11:20 PM

Heater connections on engine for a 2001 Xstar
Hey all,

I am building a DIY heater for my 2001 Xstar with the 5.7l injected Indmar 330hp motor.

Can anyone point me in the right direction on where to find the heater water feed and return on the motor?

Pics would be ideal as I think I have found a couple of possible bungs on the port side of the motor near the back, but not sure which it correct.

wheelerd 06-12-2013 12:18 AM

Check out this thread.
It has some good pics and info. It shows an MCX but the hookups are the same for your engine.

TURSTY 06-16-2013 07:20 AM

Thanks for the link. I have had a look over my motor and it looks slightly different. The fuel rails on my engine seem to be joined at the back and the joiner hoses run straight over the heater outlet by the looks. Has anyone got around this issue before? Im not sure any kind of fitting would clear the lines, even a 90* bend =S.

bigmac 06-16-2013 08:23 AM

Yah, that's tight quarters. All you need is a hose barb for a 5/8 line. On the MCX, there's a 45 degree angled brass fitting and a valve. That is the place where you want your supply line.

The return line is a similar plug on your engine's circulating pump. Depending on the boat, might be kind of hard to get to. IMHO, using a Y-pipe for the return line is easier to deal with and additionally is more effective in that it creates far better heat output at idle or low RPM.

willg 06-17-2013 05:53 PM

I have a 2002 xstar w/ factory heater. The connection is in a different place. I'll go take some pictures now.

wheelerd 06-17-2013 07:38 PM

2 Attachment(s)
Here are two pics from my former 01 X5. The supply line is just above the water pump pulley. I just unscrewed the plug that was in the manifold and screwed in the 90 degree brass fitting. At the bottom of the second pic you can just barely see the Y of the return as it enters the raw water intake hose.

willg 06-17-2013 09:27 PM

On my boat, 2002 X-star (5.7L LTR engine) w/ factory heater, the valve is on the side of the block, between the spark plugs and under the manifold. It was really hard to get a good picture with the dividers in, I'll try to take a better one tomorrow. In the second picture, you can see the brass valve right in the center of the image between the exhaust. I have no idea where the water returns to the engine.

TURSTY 06-21-2013 07:56 AM

Had a look at the boat today.

The port on the front of the waterpump is in use by a sensor:

It looks like there are two ports on the side of the heads like in your pics willg. One on each side.

Does anyone know what the coolant path through these motors is? i.e. which head would have the hottest water coming out of it?

Locations (not my motor, but a pic from google):

Starboard side:

Port side:

wheelerd 06-21-2013 08:56 AM

Coolant flow on a GM small block (with the exception of the LT1):
- in from raw water pump (in from lower rad in a vehicle)
- out back of water pump into front of block
- through block up into intake manifold
- past thermostat
- out to exhaust risers (out to upper rad in a vehicle)

Because of this flow your hottest water will be right before the thermostat. That's why the heater supply hose typically comes out of the intake manifold (as my earlier post and the pic of the MCX shows.)
The hot water supply for my shower comes from the LH side of engine (V drive, so starboard side of the boat) at the drain plug hole.

uplander 06-21-2013 10:52 PM

can you post a pic of your DIY heater box

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