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Heater fan blows but no heat


iliketoski

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Hey Guys,

My daughter just bought a 04 Supra Comp (I know this is a Malibu Forum :-)), but is the best resource out there.  Anyway I've been helping to troubleshoot some things not working and came across the heater not working.  I found that the fuse for the fan was blown, that was a quick fix, the fan now blows, but nothing but cool air.  I've never had a heater, but thought it is only a coil that hot water circulates from the engine with the a fan blowing across it.  In searching the forums I see mention of a pump in some cases, but I think that is on more current models, (I couldn't find any pump in the system unless it is in the heater box, which I can't get to based on where it is mounted.  I haven't totally traced the water lines, but would there be shutoff valves on them?

I saw mention of a Y Valve, what is the purpose of it and where would it go?  

Last question... How do you winterize them, would antifreeze just circulate through the coil when doing the winterizing the rest (assuming I actually have flow, which could be the no heat problem).

Thanks in advance.

'ski

Edited by iliketoski
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I have seen shut off valves on older boats, usually MasterCraft. But my guess is either a line is blocked/crimped/smashed, or, someone took the core out cause it was leaking and capped the lines at that end ( I see this alot).

Its is possible you just arent getting any hot water up to the core, usually without a pump you need to get the motor under a load so the water can circulate good.

We pull the heater hoses off on freshwater cooled boats and blow them out to get all of the water out of the heater, the core is thin copper tubing and it will be the first thing to crack when its get below freezing.

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I could feel that the coils were still there, when I had the hoses off they were below the openings.  Since the fuse was blown on the blower, I'm not thinking the coils were removed.  I guess I'm going to go down the path of there being a blockage.  I assume you blow out the core after you drain the block?

Edited by iliketoski
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  • 3 weeks later...

Well time got away from us and we never got to check this further, now the question, how to winterize the heater?

My guess is warm the engine, drain the engine, blow out the heater coil (small compressor), run engine with antifreeze. 

My concern is that there is no flow to the heater, so will I be able to blow out at all?

'ski

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If you can't blow the heater out, just hook up a new piece of hose that is closer to the core.  Temporary solution that you can fix when you have time.  Plus it will tell you if you have a plugged line :-)

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Blowing out the heater line with a compressor will tell you if it is blocked. If so can you remove the heater core outright and store it inside? I winterized mine by blowing it out of water first then funneling a bunch of antifreeze in and blowing through until I saw some come out of the return hose. If you have a pump you can try having the pump send the antifreeze through the heater hose circuit. If it is blocked it is probably fine if the hose has some water in it but you don't want the heater core/coils to have water freeze in it over the winter.

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  • 4 weeks later...

Ok, so we are getting ready to winterize and spent some time looking at the heater.

Tracing the lines......guess what, they are not connected to the engine!!!!! We won't get any heat that way!

For some reason previous owner disconnected it.  Maybe because the fan didn't blow (found a blown fuse), or maybe the coils leak.  We did blow air through it no problem, next will be to plug the end and put some water under pressure and see if there are any leaks.  Since it is already blown out, that will be a spring project, no sense adding more work now.

Soooooo the question I have, where are the supply and return hoses supposed to connect to the engine.  And, I've read a little about a installing a special "Y" connector, purpose?  Where?

I tried to research installation, from what I read, they talk about a plug on the front of the intake manifold near the thermostat, and the other line going to a plug on the water pump housing.  I've had the water pump off and can't recall a plug there?  Does this sound right?  Any info on where to connect would be apprciated

We are going to the boat this weekend and winterizing, I'd like to figure out how the hoses should be hooked up, (pre planning for spring project).

'ski

Edited by iliketoski
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Is the engine a GM 5.7L, or something else?  You didn't say, and I am not familiar with Supra.

If it's a GM, the plug in the circulating pump is just above the J-Hose.  The Y fitting improves your heat at idle, but you could also do that with a small electric pump.  You'll want a 5/8" barb for each place on the engine, and a male-female elbow at the manifold so that barb doesn't stick straight up.

My guess is that the heater core froze, so hooking it up is going to cost you a core.  A late '90s chevy pickup might be a good starting place to hunt one up at the auto parts store, and it should be fairly cheap.  Pull your old one and take it with you to make sure you get one that fits your housing.

 

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 In my 02, the heater coil was a match to a late 80's ford van if i recall correctly. Definately take it with you.

 Do be careful when you try to blow out the lines, high pressure air will burst the core if its not already toast. I turn my air down to 10 psi before blowing out the water, then use a small funnel to fill the core directly, pour into one and wait for it to come out the other, takes about 1/2 a gallon in my response. 

The y fitting goes in the raw water line, to improve circulation, especially at low rpm.  there is a great article here somewhere about installing it.

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32 minutes ago, asnowman said:

 In my 02, the heater coil was a match to a late 80's ford van if i recall correctly. Definately take it with you.

 Do be careful when you try to blow out the lines, high pressure air will burst the core if its not already toast. I turn my air down to 10 psi before blowing out the water, then use a small funnel to fill the core directly, pour into one and wait for it to come out the other, takes about 1/2 a gallon in my response. 

The y fitting goes in the raw water line, to improve circulation, especially at low rpm.  there is a great article here somewhere about installing it.

I blow the water out with my lungs. I have a 04 and agrre that it was from a 80 van. Take the coil and the box and make sure it fits back in the box and you have room to put the hoses back on. 

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53 minutes ago, asnowman said:

 In my 02, the heater coil was a match to a late 80's ford van if i recall correctly.

Would be nice to have an exact spec as when I needed to replace mine a few years ago, no auto parts or rad shops could match it.  Bought replacement from Heatercraft and got killed on shipping.

 

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On 10/18/2019 at 6:11 AM, iliketoski said:

Thanks, unfortunately the install PDF is a dead link.

https://cdn.bakesonline.com/media/resourcelibrary/HeaterLowRPMReturn.pdf

The above is for the heater exit.

 

Does this help?

https://cdn.shopify.com/s/files/1/2217/2701/files/Marine_Heater_Kit_Manual.pdf?16394032568051658891

 

 

Edited by formulaben
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Yes that does help!  I have a shower so I'm guessing I'll have to put a T to add the heater as well.  It is opposite the knock sensor, I'd rather not mess with its operation.  If I don't use the "Y" ($50 for a plastic fitting, really?) where would the return go to?

 

'ski

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11 minutes ago, iliketoski said:

Yes that does help!  I have a shower so I'm guessing I'll have to put a T to add the heater as well.  It is opposite the knock sensor, I'd rather not mess with its operation.  If I don't use the "Y" ($50 for a plastic fitting, really?) where would the return go to?

 

'ski

That $50 will be some of the best money you ever spend , no heat at idle to very very warm air at idle snd almost hot under way snd it’s powder coated brass(I thought it was plastic too).

some have done same thing  as mentioned above with a $10 Amazon pump right at heater return line under dash  as it exits core and Hooked up to fan switch (heatercraft pump $150) and they have heat with no motor on as well as improved performance at idle snd under way

 

Edited by granddaddy55
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I'll have to see if I can find that out.

We looked over the engine in detail on Sunday, for the life of me I can't figure out where the heater was ever connected, nothing capped or anything.  I'm still trying to figure out where to T off for the hotwater supply.  We decided to remove the shower since it will never be used, the hotwater feed for that comes off the side of the block.  While you could go from there, seems like a small supply.

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I called Heatercraft, unfortunately there is a restrictor in the 5/8" section, he said it's like a pinhole.  (I'm guessing larger than that, but obviously not the full 5/8").

I asked them questions about where to tie in the lines, I was surprised how un-helpful they were.  Considering a Indmar is pretty common, he kept saying all engines are different and the instructions are meant to be vague.  A lot of help they were.

Edited by iliketoski
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36 minutes ago, iliketoski said:

I'll have to see if I can find that out.

We looked over the engine in detail on Sunday, for the life of me I can't figure out where the heater was ever connected, nothing capped or anything.  I'm still trying to figure out where to T off for the hotwater supply.  We decided to remove the shower since it will never be used, the hotwater feed for that comes off the side of the block.  While you could go from there, seems like a small supply.

That's the block drain.  You won't get water in your heater that way.  Assuming it's a GM 5.7L, there should be a fitting or a plug atop the manifold next to the thermostat.  That's the heater "out" location.  Heater "return" location is to a fitting on the side of the recirc pump.  With the heater Y adapter, that gets moved to the raw water intake line.  People like this for heat at idle.

I solved my heat at idle solution a different way.  Worked great this morning when it was 55F.  Felt like Florida in my drivers seat even with the engine off.

 

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11 minutes ago, UWSkier said:

That's the block drain.  You won't get water in your heater that way.  Assuming it's a GM 5.7L, there should be a fitting or a plug atop the manifold next to the thermostat.  That's the heater "out" location.  Heater "return" location is to a fitting on the side of the recirc pump.  With the heater Y adapter, that gets moved to the raw water intake line.  People like this for heat at idle.

I solved my heat at idle solution a different way.  Worked great this morning when it was 55F.  Felt like Florida in my drivers seat even with the engine off.

 

It is the 5.7.  I noticed on the right side of the thermostat is a sensor. then on the left side (same place) is a plug in the top of the manifold.  I kept looking for something that had been reinstalled or capped, since the heater is now disconnected.  The plug I found still has the original engine paint over it.  Is this what you are referring to?

I like your mod, I want to see how it will work without the "Y" or a pump, then decide which way to go, I need to get it hooked up first though. I didn't see the fitting on the recirc pump, (top, side, bottom?)

Thanks for your response.

 

Edited by iliketoski
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58 minutes ago, iliketoski said:

It is the 5.7.  I noticed on the right side of the thermostat is a sensor. then on the left side (same place) is a plug in the top of the manifold.  I kept looking for something that had been reinstalled or capped, since the heater is now disconnected.  The plug I found still has the original engine paint over it.  Is this what you are referring to?

I like your mod, I want to see how it will work without the "Y" or a pump, then decide which way to go, I need to get it hooked up first though. I didn't see the fitting on the recirc pump, (top, side, bottom?)

Thanks for your response.

 

Are you sure the engine is original?  If so, are you sure the heater was ever actually hooked up?  That painted plug is what you'd remove to install the heater feed.

If looking at the pump head on, it comes in around the 9:30 oclock position above the J hose.  Here's mine.

 

IMG_20191021_145312.jpg

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8 hours ago, iliketoski said:

The plug I found still has the original engine paint over it. 

No reason to believe that any paint you find on the engine is original.  I touched mine up after I installed closed cooling, riser gaskets, and the heater.  Pretty easy to match black paint.

I do recall having to bear down to get that plug to loosen because it was painted in place. 

I also installed the little electric pump that @UWSkier mentioned for better circulation and it always feels like Florida to me, too.  Oh, wait... I *am* in Florida!

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You know I'm beginning to wonder if it was ever hooked up at all.  I've located both plugs and neither one has any sign that it has ever been touched, (given the shape of the boat overall, I highly doubt they would ever touchup the paint on the plugs).

I have no reason to suspect the engine was ever replaced, the boat doesn't have a ton of hours on it (500), and the looks of things support that.

Any idea what size fittings I need (the hose is 5/8" ID?).  (Obviously, when I take the plugs out I'll know), I want to get them in advance if possible,  I'm thinking they are NPT with a 5/8" barb on the other end.

 

Edited by iliketoski
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