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Heater Y fitting Mod


LateNightSalami

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So my heater has the typical behavior of not working unless we are at higher speed. I looked around on the forums and noticed a few options to correct this. One being a circulator pump for the heater system, the other using a Y fitting to the raw water impellor to help circulate through the heater. Well as I am going through my first winterization this year I noticed that my heater system already had the Y fitting (I found the hose that goes too the heater quickly, took me forever to find the one going from the heater back to the engine). I think it is in the wrong spot to really work though. The Y fitting is attached to the tube that comes after the impellor. So my plan is to get some extra hose and re-plump it so that it is just before the impellor. As I understand it, with this newer configuration the impellor will help suck engine water through heater circuit which will help keep the heater warm at lower speeds. A few questions:

 

1. I am planning on putting a valve on the Y fitting so I can stop the re-circulation of the heater water back into the engine. I am worried a bit that this setup could trigger overheating of the engine since you are re-circulating warm water. Is this something I should even be concerned about?

2. This job seems pretty straight forward: add a bypass to the Y fitting's current location. Cut the hose going into the impellor and install the Y fitting there, add hose to allow the heater hose to reach the Y fitting. Is there anything else I would need to be worried about?

 

Thank for any input

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Easy modification.  Lots of people have done it.  Don't need to worry about recirculating heated water.  There's a reducer inside the Y adapter that restricts the water flow through the heater circuit to a few GPM.  It's nothing your engine will even notice.

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Salami, the hot water that goes to the heater has some of the heat taken out of it by the heater core pulling air past the core. The returning water will be cooler than the incoming water.

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22 hours ago, UWSkier said:

Easy modification.  Lots of people have done it.  Don't need to worry about recirculating heated water.  There's a reducer inside the Y adapter that restricts the water flow through the heater circuit to a few GPM.  It's nothing your engine will even notice.

Yep.  That's right.

 

Also, keep in mind, boat engines run significantly cooler than their auto counterparts since they are getting nice cool fresh water all the time.  Your car engine's incoming "cool" water is what is coming back from the radiator which is plenty hot enough you wouldn't want to touch it.  The heater core acts similar to the car radiator so it is cooling the water a bit.  Plus, as UWSkier said only a small portion of the water going into the engine flows through the heater, the majority is nice fresh cool lake water.

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32 minutes ago, ahopkinsVTX said:

Anyone foresee any issues using a wye pipe on a v drive? It’s still just tap into the raw water line just before the impeller right?

not sure of the flow on the new ones, but with the Walter V-drive, the water went straight from the through-hull, into the V-drive housing, then to the impeller.  Could put it before or after the tranny on those no problem.  Wouldn't imagine it matters much on the newer ones.  Isn't your engine partial closed cooling though?

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ahopkins22LSV
34 minutes ago, UWSkier said:

not sure of the flow on the new ones, but with the Walter V-drive, the water went straight from the through-hull, into the V-drive housing, then to the impeller.  Could put it before or after the tranny on those no problem.  Wouldn't imagine it matters much on the newer ones.  Isn't your engine partial closed cooling though?

 Nope it’s 100% raw cooling. This diagram is basically 100% accurate, on difference is that the intake is at the very back of the boat so hose from the strainer to the pump is only a foot and a half or so. Heater lines run right by it so should be quite simple.

752A18A9-18AC-4771-9B14-0154F4739021.thumb.jpeg.acfdf984407e093b62bee7b87b73e641.jpeg

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Can you put it between the intake and the strainer?  Would give you and extra measure of filtration that way.

BTW, I'm headed to the lake in about an hour and will report back on how the el-cheapo pump works for heat at idle.  I'm not using the Y.

Edited by UWSkier
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ahopkins22LSV
32 minutes ago, UWSkier said:

Can you put it between the intake and the strainer?  Would give you and extra measure of filtration that way.

BTW, I'm headed to the lake in about an hour and will report back on how the el-cheapo pump works for heat at idle.  I'm not using the Y.

I think so. But shouldn’t everything already be strained? And agreed on the on offs. I think I will add those as well. 

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Holy crap...do you have any idea how hard it is to find simple hosing and metal piping segments (to attach the cut hoses together) for this project? Nothing at the dealer, home depot doesn't sell anything in 5/8''. I am calling a plumbing store or HVAC store next to see...just giving others a heads up to go right to those if needed.

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40 minutes ago, LateNightSalami said:

I was trying to avoid having to order it online since I wanted to finish the project today...the stores I have called around to/visited don't keep them in stock.

Are you needing to order these to add the bypass?  If you're just relocating the Y, the only thing I can think of that you'd need for this project really is a coupler to splice the after-impeller hose together where the Y used to be.

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On ‎10‎/‎19‎/‎2018 at 11:27 AM, John I. said:

I found this pic (which I probably grabbed from this site many years ago) on my hard drive.

 

Y-Pipe%20Picture.jpg

That's my install!!  :lol:.    Never had an issue with overheating.   Temp is pegged at 160 all the time.   The heat does get cooler at idle, but it's still warm

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57 minutes ago, UWSkier said:

Are you needing to order these to add the bypass?  If you're just relocating the Y, the only thing I can think of that you'd need for this project really is a coupler to splice the after-impeller hose together where the Y used to be.

Yeah I need two couplers. One to splice the after-impeller hose together the other to run extra 5/8'' hose from the heater core to the other side of the engine compartment (about 2-3 ft) to reach the before-impeller hose where the Y will be moved to. When calling around I can't really find a place that has the right sized couplers that I need.

The 5/8'' line running from the heater core currently runs along the starboard side of the engine compartment and connects to the Y right before transmission cooler screen. There isn't any extra hose so I have to add hose and loop it behind the engine a bit so it will reach the new Y location (on the hose going into the impeller).

Edited by LateNightSalami
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36 minutes ago, CedarLakeSkier said:

That's my install!!  :lol:.    Never had an issue with overheating.   Temp is pegged at 160 all the time.   The heat does get cooler at idle, but it's still warm

Have you ever had any reason to close the valve to shut off the flow from the heater core?

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On 10/19/2018 at 11:27 AM, John I. said:

I found this pic (which I probably grabbed from this site many years ago) on my hard drive.

 

Y-Pipe%20Picture.jpg

Now I am intrigued and would like to do the same.. from the raw water pump where are you routing the hose to? I see the wye, but where does it end at?

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21 minutes ago, kerpluxal said:

Now I am intrigued and would like to do the same.. from the raw water pump where are you routing the hose to? I see the wye, but where does it end at?

So the whole circuit is typically as follows:

-From the top of the engine circulator housing to the heater core

-From the heater core to somewhere back into the engine cooling system

The modification that is done is to put a wye in from of the raw water pump and take the second half of the loop and end it there. The idea is the raw water pump helps pull water through to the heater core improving the flow at low RPM which in turn improves the heat output at low RPM. So technically the hose exiting from the heater core is being route TOO the before-hose to the raw water pump.

 

Edit: I hope that helps

Edited by LateNightSalami
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21 minutes ago, kerpluxal said:

Now I am intrigued and would like to do the same.. from the raw water pump where are you routing the hose to? I see the wye, but where does it end at?

Does your boat have a heater?  I believe Malibu started including the Y by default at some point, but I'm not sure which year got this.  Unfortunately, where Malibu installs them is pointless as they're AFTER the raw water pump.  To get the suction effect required, it needs to be moved into the feed line from the through hull to the raw water pump.

If you don't have the Y adapter from Malibu, that means your heater return line goes into the water circulation pump.  This is the "default" location for the return water.  What I and a number of other folks have done instead is install a cheap pump to help push water through when the boat is at idle.  That may be an easier option.

The pump also makes it easier to pass anti-freeze through the core BTW.  :)

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1 minute ago, UWSkier said:

Does your boat have a heater?  I believe Malibu started including the Y by default at some point, but I'm not sure which year got this.  Unfortunately, where Malibu installs them is pointless as they're AFTER the raw water pump.  To get the suction effect required, it needs to be moved into the feed line from the through hull to the raw water pump.

My boat is a 2008 so they at least started it then.

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12 minutes ago, UWSkier said:

Does your boat have a heater?  I believe Malibu started including the Y by default at some point, but I'm not sure which year got this.  Unfortunately, where Malibu installs them is pointless as they're AFTER the raw water pump.  To get the suction effect required, it needs to be moved into the feed line from the through hull to the raw water pump.

If you don't have the Y adapter from Malibu, that means your heater return line goes into the water circulation pump.  This is the "default" location for the return water.  What I and a number of other folks have done instead is install a cheap pump to help push water through when the boat is at idle.  That may be an easier option.

The pump also makes it easier to pass anti-freeze through the core BTW.  :)

Yes, 2010 LSV... All I know is that at low idle, no heat... 

What is antifreeze for :whistle:... I am usually down only 2 weeks and it rarely freezes here :thumbup:

So a 500 gph pump? then I can but a Y on that and have a heater shower as well??? 

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31 minutes ago, LateNightSalami said:

So the whole circuit is typically as follows:

-From the top of the engine circulator housing to the heater core

-From the heater core to somewhere back into the engine cooling system

The modification that is done is to put a wye in from of the raw water pump and take the second half of the loop and end it there. The idea is the raw water pump helps pull water through to the heater core improving the flow at low RPM which in turn improves the heat output at low RPM. So technically the hose exiting from the heater core is being route TOO the before-hose to the raw water pump.

 

Edit: I hope that helps

perfectly understand now, return hose from heater to before raw water pump... this would make draining easier as well... then cap the old re-entry?

Edited by kerpluxal
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