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View Full Version : adding a shut off valve for heater?


skiknox
10-22-2012, 09:36 PM
I just replaced my heater core in the old heater on the 95 ps205 lt1 and i want to add a shut off valve where to brass barbed fitting comes off the engine. Anyone know of a threaded to hose barb valve i can use?
thanks,
Ben

wheelerd
10-23-2012, 01:48 AM
Here's a pic from my MCX. Valve is just on the left of the photo above the valve cover. Return barb is down by the pulley. (Hoses are off for winterization.) I don't know the exact specs of the shutoff valve but they do exist. You can likely find one at Lowes or Home Depot.

TRBenj
10-23-2012, 10:46 AM
I assume this would be so that you could turn off the water loop through the heater core, should it break again? A valve obviously wouldnt help for draining (winterizing), though some quick disconnects would.

I think it would be very difficult to find a valve with hose barbs built in. Its easy to find a proper sized ball valve with female NPT threads that can accept a hose barb fitting x NPT male thread on each end, though. Assuming your heater lines are 5/8" ID, I would grab the appropriate quantities of the following part numbers from McMaster. (http://www.mcmaster.com)

5346K66
47865K23

Ben
10-23-2012, 10:52 AM
No help on the valve (yet), but can i ask where is your heater located and what all outputs do you have? I'm trying to figure how to stuff one in a 94. Pictures?

CiscoStu
10-23-2012, 11:02 AM
On the MCX, the valve is actually on the RETURN side of the circuit that goes to the heater core. Turning off the valve doesn't prevent water from going through the heater core, it only stops it from going back into the block. You need a fully sealed system (no leaks) for the valve to do any good.

wheelerd
10-23-2012, 11:17 AM
On the MCX, the valve is actually on the RETURN side of the circuit that goes to the heater core. Turning off the valve doesn't prevent water from going through the heater core, it only stops it from going back into the block. You need a fully sealed system (no leaks) for the valve to do any good.

Depends where that valve is. On my MCX (pic above) the valve at the intake manifold is on the pressure side. Water circulation in the typical GM small-block (with the exception of the LT1) is: in through the bottom rad hose, through the block, up through the heads, out the intake manifold via the thermostat.

Ski-me
10-23-2012, 11:17 AM
In my 94' the heater box is under the dash, wedged in by the steering column. It does look tight but it does work, too. I have 2 hoses, one to the driver's feet and the other just to the left of driver, between walkway to front.

CiscoStu
10-23-2012, 11:22 AM
Wheelerd, you can see that the non-valve side is on the water pump... It's a push, not a pull.

I went through h*ll with my local dealer when I poked a hole in my heater core. I knew it had a hole in it when I de-winterized the boat, so I called and asked if turning the valve OFF was all I needed to do. The mechanic said, "Yup", turning the valve off prevents water from going to the core. WRONG! With the valve off, the heater core was leaking water to the tune of about 1-2 gallons/minute. Thats a lot of water going onto the carpet and down to the bilge.

That valve will only stop water going to the heater core if it's a sealed system...

wheelerd
10-23-2012, 11:31 AM
I beg to differ. See http://wiki.answers.com/Q/Coolant_flow_v8_diagram
That's why the return line from the heater is sometimes Y'ed into the raw water pump supply line so that it draws better and provides better circulation at idle.

skiknox
10-23-2012, 12:20 PM
mine feeds dead in the center right below the k&n filter, not trying to use for winterization just to shut water from always circulating through core when not in use.

TRBenj
10-23-2012, 12:22 PM
If you dont want the heater core to leak, I would strongly consider putting a valve on both the feed and return lines... if nothing else, to prevent the water from running back up there when the engine is shut off.

CiscoStu
10-23-2012, 12:23 PM
Regardless, the valve in the photo is on the return line...

And TRBenj, that's a great idea, but it's pretty tight to get a valve in down by the pump...

TRBenj
10-23-2012, 12:59 PM
Regardless, the valve in the photo is on the return line...

And TRBenj, that's a great idea, but it's pretty tight to get a valve in down by the pump...
I wouldnt be putting them right on the block/intake/pump/etc. I'd be putting them somewhere in the 5/8" line. Lots of room in the bilge.

skiknox
10-23-2012, 06:14 PM
yeah i guess that would be much easier to just cut intake and return line in bilge and put shut off valves inline. For winterizing could you just take lines enter heater and let core drain?

jakethebt
10-23-2012, 09:46 PM
The original question was for a shut off valve on an LT1. I have an LT1 with a heater and it comes off the top of the thermostat just like this pic, but it does not have a valve. This pic is one I saved from when UncleBoo was selling his '98. I too would be interested in where this valve can be had. Also of note this is NOT the "improved" LT1 heater location discussed in detial in another thread. The LT1 improved location has you remove the temperature sensor and "T" off that for better idle heat. Others have drilled and tapped a new hole on the water pump housing to mirror the temperature sensor fearing that the "T" may affect the reading of actual temp reading.

wheelerd
10-23-2012, 10:40 PM
Regardless, the valve in the photo is on the return line...

And TRBenj, that's a great idea, but it's pretty tight to get a valve in down by the pump...

Hey there neighbor up Hwy #2, not to start a pi$$ing contest, but what is your evidence that on standard GM small blocks, ie. non-LT1 engines, the hose at the top of the manifold (where the valve is on my MCX pic) is the return line?

Have a look at post #6 on this thread: http://www.mastercraft.com/teamtalk/showthread.php?t=32897&highlight=path+flow
Same MCX pic as mine, and same explanation as mine. (Note that he uses "inlet" and "outlet" with reference to the heater core, not the engine.)

If further proof is needed . . . quoting from the HeaterCraft Acu-Heat Install Manual p. 7 (which is the typical system we have on our boats) http://heatercraft.com/content/Installation/Heater_Instal_Marine.pdf
"The output hose is connected to the intake manifold or thermostat (on most V8 gasoline engines). The return is connected to the water pump or the large hose between the thermostat housing and the water pump (on most V8 gasoline engines."

When you think of it logically, adding a shut-off valve at the end of the return line would be pointless. Any leaks in the hoses or in the heater core would continue to leak because they would still be on the pressure side.

skiknox
10-24-2012, 07:48 AM
jakethebt, that is that same place my line is coming off my lt1 as in the pic but dont have the shut off. like to add one though.

beef
10-24-2012, 09:31 AM
I've done a few heater installs and always put a garden hose Y adapter in place on both the output and return side. This allows the heater to be shut off in the summer, and by flipping the valves you can easily blow out the heater for cold nights in the fall, or pour in antifreeze for winterizing.

CiscoStu
10-24-2012, 09:49 AM
Wheelerd, I don't think it's a pi$$ing contest, just a good conversation over how we each think it works... I'll even buy you a box of your favorite (Canadian!) brew to show you what I'm talking about this spring if you make the trip to Cowtown.

Like I said in my earlier post, when I sprung a leak in the heater core, I thought shutting the valve off was all I needed to do to get going again - WRONG! As the valve is on the return side, the heater core itself was still leaking. As I mentioned, I even asked a mechanic and a sales guy if turning off that valve would stop the leak, they both said it would. WRONG!. I bought a 5/8" - 5/8" barb adapter to connect the hoses together and bypass the core, then when I bought the new core everything was good.

Turning off that valve and running the motor, it was still pumping out water through the core, onto the carpet, into the bilge, etc. Small hole in the core, but it sure was coming out fast..!

So, let's have a few brews and sit in the boat and figure it out... If that valve doesn't truly shut off water to the heater core, then the only thing it's really good for is controlling water flow to *maybe* moderate the temperature? i.e., turn the valve to restrict water, and make the heater run a little less hot.

TRBenj
10-24-2012, 10:39 AM
I know very little about small block Chevies in general, but I do know that the LT1 with its aluminum heads was a reverse cooled motor. I do not believe the typical Vortec 350 (like the MCX) was. Id still be shutting off both supply and return lines to be sure you werent getting unwanted water flow through the heater core, regardless.

I too would be interested in where this valve can be had.
See post #3 in this thread.

wheelerd
10-24-2012, 12:50 PM
Wheelerd, I don't think it's a pi$$ing contest, just a good conversation over how we each think it works... I'll even buy you a box of your favorite (Canadian!) brew to show you what I'm talking about this spring if you make the trip to Cowtown.

Like I said in my earlier post, when I sprung a leak in the heater core, I thought shutting the valve off was all I needed to do to get going again - WRONG! As the valve is on the return side, the heater core itself was still leaking. As I mentioned, I even asked a mechanic and a sales guy if turning off that valve would stop the leak, they both said it would. WRONG!. I bought a 5/8" - 5/8" barb adapter to connect the hoses together and bypass the core, then when I bought the new core everything was good.

Turning off that valve and running the motor, it was still pumping out water through the core, onto the carpet, into the bilge, etc. Small hole in the core, but it sure was coming out fast..!

So, let's have a few brews and sit in the boat and figure it out... If that valve doesn't truly shut off water to the heater core, then the only thing it's really good for is controlling water flow to *maybe* moderate the temperature? i.e., turn the valve to restrict water, and make the heater run a little less hot.

Hey, let's do the brew! Big Rock will be just fine.

I have a simple explanation that reconciles both our "truths."

I have no doubt that what you say is true -- when you turned off the tap the heater still leaked.
I have no doubt that what I say is true -- the coolant flow through the typical GM smallblock is as I (and your sales and tech guy, and the other evidence I presented) indicated. I've worked on Chevy engines for 35 years so kinda have this figured out.;)

Here's what I think happened: the shut off valve did not completely stop the flow of water. Given the operating conditions of our raw-water-cooled engines, consider how common it is for sand and other crud to be drawn up into the engine. Note how much rust and grit come out when you pull the block drain plugs to winterize. A small grain of sand, or a piece of impeller, or even corrosion, might cause the shut off valve to not close completely. Even the smallest amount of water bypass would maintain positive pressure to the heater core and cause a leak.

Here's a pic of the heater hose routing on a HeaterCraft install I did on my former boat which had the RTP engine.

The fitting/hose right above the waterpump pulley comes off the front of the intake manifold and is the pressure side. At the very bottom of the pic you can see the return hose Y'ed into the raw water supply hose. I ordered this from SkiDim on the advice of other threads here on TT on this subject. You can see the part at: http://www.skidim.com/prodinfo.asp?number=H424 The description clearly states, "This fitting relocates the return line for the heater to the inlet side of the raw water pump, increasing water flow thru the heater core at idle speeds."

I don't know if you've seen the reverse side of a typical water pump so here's a pic also. The pressurized coolant flows out the back of the pump through the two arms that attach the pump to the block and thus feeds each bank of cylinders. Depending on the application there ARE sometimes heater supply and/or return ports on the waterpump. Sometimes they are used, sometimes they are blocked off. Referring back to the original pic of my MCX, the heater hose going to the water pump is attached to one of these return ports which feeds into the same intake chamber as the big fat hose (which is the bypass from the thermostat housing on a marinized open-cooling system, or on a car would be the return hose from the bottom of the rad.)

Jorski
10-24-2012, 02:31 PM
If you shut off a single valve, and your core has a leak, it is still going to leak.

The pressure of the coolant flow inside of the block will push water in reverse (up the return line) back toward the heater core as it has lower pressure; given the leak. If you want to be able to isolate the heater and hoses in the event of a leak, you would need two shut-offs, one on the outbound flow, and one on the return. Ciscostu, this is why your return appeared to be the supply hose.

If you shut off a single valve (let's say on outward flow), and you don't have any leaks, that will shut-off the heater, (stopping circulation of warm water) as the heater and both lines (in and out) will be pressurized equally to the coolant water inside of the engine, thus no reversing of flow.

wheelerd
10-24-2012, 04:49 PM
Good point. I would suspect that's particularly true when the return hose is plumbed into the water pump. When it's Y'ed into the raw water supply line (like in my RTP pic above) maybe less so, since the flow of the incoming water causes negative pressure (ie. suction) on the heater return line, thus promoting better circulation through the heater. That is, after all, the point in having the Y adapter.:)

david_ski
10-25-2012, 01:25 AM
I put in 2 1/4 turn ball valves into the heater lines. In addition I added brass T's in line on the heater side. To winterize or during summer, valves closed and take the plugs out of the T's and blow air through heater core to empty. Replace plugs and heater core and feed/return lines are empty. Without the shutoff's and cleanouts I was loosing a core about every 2 years in the water we ski in.

Memo
10-25-2012, 03:42 PM
Wheelerd do you have a hot water shower installed on the boat as well? If you do where is the intake for the hot water side located?
Thanks!

wheelerd
10-25-2012, 09:06 PM
Wheelerd do you have a hot water shower installed on the boat as well? If you do where is the intake for the hot water side located?
Thanks!

Yes, I have the shower. I've actually only owned my X2 for a couple of months so I'd have to look to be sure. If I remember correctly from when I winterized it, the hot water hoses comes from the LH drain port on the block (ie. starboard side of the boat.) If I happen to be poking around in it in the next little while I'll confirm for sure.

eurosysytem0
10-26-2012, 05:50 AM
Guys this thread has confused the hell out of me but I have a similar issue. I have a 2005 X7 with a MCX 350 engine. I also have a heater in the drivers footwell which I never use but is always a real pain to empty/drain when I winterise the boat.

The engine has a valve on the "upper" hose. ( I dont know if its flow to or from engine)
There is no valve on the bottom hose.

Ideally, I would like to drain the heater and then completely isolate from the water supply so I dont have to keep draining it.

Questions:

If I turn off the top hose tap, will it stop water getting to heater matrix so it "stays empty" or will it still get into matrix via bottom hose.

If I drain matrix and fit tap to bottom hose as well I know that water cannot get into heater matrix but will it have any adverse impact on engine/exhaust cooling

bcd
10-26-2012, 09:08 AM
I'm thinking about doing something like this:

http://www.wakeworld.com/forum/showthread.php?t=787570&highlight=heater

beef
10-26-2012, 09:52 AM
I'm thinking about doing something like this:

http://www.wakeworld.com/forum/showthread.php?t=787570&highlight=heater

That is exactly what I've done with all my heater installs. I add a short section of hose to each open end of the Y. This will let you pour anti-freeze (or blow air) into one end while putting the other end out through the drain plug hole.

Also - you do need a shutoff at both ends. I had a heater core develop a leak this past summer while the output side had it's valve shot off. It still leaked into the boat, taking enough pressure from the return side to push out water.

Memo
10-26-2012, 11:35 AM
Wheelerd - I would really appreciate it if you can check and confirm the shower pickup location for sure. My winter project is the heater install. The boat currently has the hot shower pickup on the intake manifold, where the heater pickup suppose to be. I was going to T off from the intake manifold with a check valve but if the factory shower pick up is by the side of the engine that maybe a better deal. I can just move the shower pickup hose to block drain. My 190 had the block drain pick up but this one is on top for some reason. Thanks again!

wheelerd
10-26-2012, 12:06 PM
Guys this thread has confused the hell out of me but I have a similar issue. I have a 2005 X7 with a MCX 350 engine. I also have a heater in the drivers footwell which I never use but is always a real pain to empty/drain when I winterise the boat.

The engine has a valve on the "upper" hose. ( I dont know if its flow to or from engine)
There is no valve on the bottom hose.

Ideally, I would like to drain the heater and then completely isolate from the water supply so I dont have to keep draining it.

Questions:

If I turn off the top hose tap, will it stop water getting to heater matrix so it "stays empty" or will it still get into matrix via bottom hose.

If I drain matrix and fit tap to bottom hose as well I know that water cannot get into heater matrix but will it have any adverse impact on engine/exhaust cooling

Understandable confusion! Here's the deal:

- Pressure (ie. supply) for the heater comes typically from the intake manifold, since that is where the water is the hottest before exiting the engine. But it could also come off the block as seen in the video a couple of posts above.
- Return can be anywhere that has less pressure than the supply.;) That could be an intake port on the water pump or Y'ed into the raw water supply hose or some other point in the system.
- Under NORMAL circumstances a shut off tap/valve on the supply hose should cut off water to the heater. Caveat: the tap might have an internal leak or be partially blocked open, or if the heater core or return hose has a leak, there might be enough pressure in the system to push water back up the return hose.
- Adding a shut off valve on the return line would completely isolate the heater core.

Bypassing the heater will have no adverse effect on the engine operation. Heck, many of the boats come without a heater.

If, as it sounds, you want to bypass the heater permanently, then just remove the supply and return hoses at the engine and cap the fittings.

wheelerd
10-26-2012, 12:07 PM
Wheelerd - I would really appreciate it if you can check and confirm the shower pickup location for sure. My winter project is the heater install. The boat currently has the hot shower pickup on the intake manifold, where the heater pickup suppose to be. I was going to T off from the intake manifold with a check valve but if the factory shower pick up is by the side of the engine that maybe a better deal. I can just move the shower pickup hose to block drain. My 190 had the block drain pick up but this one is on top for some reason. Thanks again!

OK. I might be able to take a look this weekend.

wheelerd
10-29-2012, 01:04 AM
Memo -- Got a couple pics for you...
Yes, the hot water comes off the block as I thought. You can see it laying detached on the raw water intake hose. The cold comes off the raw water hose between the pump and the tranny cooler. (I have things detached for winterization.) Good luck on your heater install.

Memo
10-29-2012, 09:05 AM
Wheelerd - Thank You for the photos! That’s Awesome :toast:

eurosysytem0
10-29-2012, 12:40 PM
Understandable confusion! Here's the deal:

- Pressure (ie. supply) for the heater comes typically from the intake manifold, since that is where the water is the hottest before exiting the engine. But it could also come off the block as seen in the video a couple of posts above.
- Return can be anywhere that has less pressure than the supply.;) That could be an intake port on the water pump or Y'ed into the raw water supply hose or some other point in the system.
- Under NORMAL circumstances a shut off tap/valve on the supply hose should cut off water to the heater. Caveat: the tap might have an internal leak or be partially blocked open, or if the heater core or return hose has a leak, there might be enough pressure in the system to push water back up the return hose.
- Adding a shut off valve on the return line would completely isolate the heater core.

Bypassing the heater will have no adverse effect on the engine operation. Heck, many of the boats come without a heater.

If, as it sounds, you want to bypass the heater permanently, then just remove the supply and return hoses at the engine and cap the fittings.

Wheelerd
Thanks for a very comprehensive answer. Its just what I needed.
regards

wheelerd
10-29-2012, 10:31 PM
Glad to be of help. That's what this forum is all about.:D

Memo
10-30-2012, 10:46 AM
Anyone have any input on why MC is utilizing gate valves on heaters rather than ball valves? Advantage/disadvantage? I personally like the ball valves they are smaller in size, can lock in place on/off, visually verify on/off and can somewhat regulate flow. So, what am I missing?