GT40 Heater install

[8122pbrainard]

I've never seen both block drains tapped for a heater, or an block drain combined with a Y pipe.

It seams to me if you tap into both block drains for the heater you will get little or no circulation through the heater core, both fittings flowing the same way. The coolant temp sender should be just as accurate an inch or so from the manifold as it is in the manifold.

My last boat had the GT 40 and factory installed heater, it was Y'ed into the sender, worked great. Returned at the front block drain on drivers side.

Ken,
Read through this again. No one ever said both block drains. It's a block drain and the Y pipe like Joel mentioned. Block drain to the heater and the return from the heater goes to the Y pipe.

Alley,
Two different sceen names and two different locations in Scotland!! Tricky!!

[SquamInboards]

Maybe there's some slightly warmer water coming from the intake manifold, but it just seems simpler to tap into the block drain (and return through the Y). Interesting that the factory install uses the T with the temp sensor and all that extra hardware... doesn't mean it's the best way. Of course, the Y piece below the RWP is extra "hardware" too I guess.

[Sinkoumn]

I like running off of the top location for two reasons: it's hard piped directly to the shutoff ball valve ; and the ball valve is right on top for easy access to shut off the flow of water should something go wrong.

[wake_fun]

The way mine is plumbed works perfect!

[dan1166]

GT 40 Heater Install

My boat was purchased new in 1999 and I always had cool air at idle. I have researched this to death and finally installed the y adapter last year.

The hottest water is at the top of the engine at the T-stat. Sinkoumn has the right idea. Just look at his pictures. However, Sinkoumn has the y adapter installed backwards. It should be reversed.

I now have tons of heat.

Dan, the ski man

[Sinkoumn]

RE: GT 40 Heater Install

^Hmm, works like a charm where I have it installed. How is it backwards?

The return line from the heater is supposed to go through the restricted horn of the adapter before the raw water pump - work's by way of Bernoulli's principle. I'm interested to hear how it works if this isn't correct. But either way, if it's backwards I still get lots of heat at idle.

Here's another good writeup (Phat in Cincy's writeup, but this is the updated version to what was linked on wakeworld above):
http://forums.wakeboarder.com/viewtopic.php?t=54184

[dan1166]

GT 40 Heater Install

The illustration of the y connection is correct; Your actual installation is backwards. Just flip it end for end. On the illustration where it is labeled impeller, your installation has it pointed towards the fresh water intake. not the impeller. As per your illustration, If you flip it end for end, (which is the correct way)it will draw more water through the heater core. If your getting heat now, you'll get even more at any RPM's.

Dan, the skier man

[Sinkoumn]

RE: GT 40 Heater Install

I think we're talking about the same thing. That is how it's connected. :???: My ghetto picture really doesn't show the connection very well.

[TRBenj]

Re: RE: GT 40 Heater Install

I think we're talking about the same thing. That is how it's connected. :???: My ghetto picture really doesn't show the connection very well.

It looks backwards to me as well.

[Sinkoumn]

? Really? Man, fail, aha :grin:

Doesn't the water go from the connection at the T-stat through the heater line tubing, through the heater core, through the return line, and then back into the raw water intake line?

I'm really bored at work, so check the MSPaint skills! aha, is this how it's supposed to go?

[Sinkoumn]

Here is how I have mine connected:
http://www.tmcowners.com/teamtalk/at...p;d=1143139596

[TRBenj]

Actually, youre ok- assuming you have it connected like the MC diagram and not your MS Paint version. My confusion stemmed from the fact that you installed it before the strainer instead of after- Ive never seen a set up like that.

[Sinkoumn]

Yeah, I have it like the MC diagram. The MS Paint one doesn't make sense to me, but I figured I would draw it out since I've been off on all kinds of crap lately...

[dan1166]

GT 40 Heater Install

Your installation is correct. Your Y fitting is in backwards. Your drawing shows the branch of the Y fitting at 10 o'clock position. It should be in the 8 o'clock position. The purpose of the Y fitting is to draw water from the heater core. The natural flow of water on the intake side of the raw water pump will do this with the Y fitting. Your installation may draw water from the heater core but at a much, much slower rate. All you have to do is flip the Y fitting end for end. You will be amazed how much more heat you will get.

The MC drawing is correct. It is drawing water from the heater core.

Dan, the Skier Man

[dan1166]

GT 40 Heater Install

I just thought of a good example. Flowing water is like merging traffic. When you yeild on a highway, you merge with the flow of traffic; not against the flow. This is the same senario. Your heater return line is merging against the flow of water; not with the flow of water. I think this is a better explaination of what I am trying to say.
Good Luck

Dan, The Skier Man