water pump to heater core flow direction?

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simon84
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water pump to heater core flow direction?

Post by simon84 »

I'm wanting to know if the coolant flow from the water pump to the heater core goes through the metal pipe that runs under the exhaust manifold then into the heater core, back out to the heater control valve and then back into the block. This seems like the logical pathway to me but I'm not 100% sure and I know someone on here will know this.
Reason I ask is that I am installing an inline circulating water heater and it seems to have a one way flow valve. I can only blow air through it one direction. It's an old unit and I can't find much at all on the internet about installing these things.
There's also not a lot of space to fit this thing in so I may end up cutting that metal pipe so that I can tuck the heater unit under the exhaust manifold. Will want to make sure it's not too close though or it may get cooked. I have the trans and exhaust out right now so that area is fairly accessible.

Thanks for any input on this.
Driver: 87 Tercel SR5, white, 4ac, weber carb (aka the Tercedes)
Road Tripper:95 Mitsubishi Delica L400 2.8L Turbo Diesel
Motorbike: 94 Kawasaki Ninja ZX6
Project Car:Red 68 Plymouth Sport Fury III
Previous Tercel:Orange 84 Tercel 4wd (aka the pumpkin)
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Petros
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Re: water pump to heater core flow direction?

Post by Petros »

the coolant flows out of the outlet on the back of the head, goes into the heater core, and gets sucked out the long tube that runs under the manifold and goes into the back of the water pump assembly. it is easy to remember this way: the back side, center of the pump is the low pressure (suction) side of the water pump (the perimeter is the high pressie side of the impeller in the pump), and the flow in the head is on the "pressure" side of the water pump.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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simon84
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Re: water pump to heater core flow direction?

Post by simon84 »

Ok, so I had it backwards. Thanks for the info and the explanation!
Kinda makes sense that the control valve is on the pipe coming from the back of the head.
This should actually make the in-line heater install a bit easier.
Driver: 87 Tercel SR5, white, 4ac, weber carb (aka the Tercedes)
Road Tripper:95 Mitsubishi Delica L400 2.8L Turbo Diesel
Motorbike: 94 Kawasaki Ninja ZX6
Project Car:Red 68 Plymouth Sport Fury III
Previous Tercel:Orange 84 Tercel 4wd (aka the pumpkin)
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irowiki
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Re: water pump to heater core flow direction?

Post by irowiki »

What is this inline water heater for?
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87 Corolla FX16, 105k
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splatterdog
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Re: water pump to heater core flow direction?

Post by splatterdog »

Put a block heater in instead. Cheap, easy, and more effective. Having a core plug out also allowed flushing debris trapped at the bottom of the water jacket that even a Gates flush gun couldn't remove previously.

I tried a heater hose heater on my first car and it didn't work well and somehow electrified the car. Got tickled by the metal door handle when grabbed with bare hands.
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simon84
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Re: water pump to heater core flow direction?

Post by simon84 »

I already have a block heater. I live in the great white north. aka Canada.
I have not had much interior heat. I've done coolant system clean outs & flushes and little improvement.
I recently installed a hotter thermostat (180 or 185, I think, can't remember exactly).
The main reason I added the inline heater is to have heat more quickly when I start up on cold mornings.
The car is on blocks right now getting some major upgrades. Trans failed so I've now got another ready to go in. While it's up, I'm also doing exhaust, struts, dropping cross member and trans 1/2 inch (it has 1 inch lift with spacers on top of struts and pathfinder springs in back). I'm making it manual instead of power steering. Thanks to member Xirneh for trans and steering conversion tips and youtube videos.
Also playing around with hood scoop for webber carb with the large air filter, some extra gauges and a couple other fixes. I'm also adding a winch inside the grill that will have the cable feeding out through the part where the Toyota 4wd emblem goes.
It's been up on blocks since last November! It sat for most of that thanks to life and parenting in the pandemic. It's coming along now though.
I'll be sure to report back on the heat situation and post some pics of what I've been up to.
Driver: 87 Tercel SR5, white, 4ac, weber carb (aka the Tercedes)
Road Tripper:95 Mitsubishi Delica L400 2.8L Turbo Diesel
Motorbike: 94 Kawasaki Ninja ZX6
Project Car:Red 68 Plymouth Sport Fury III
Previous Tercel:Orange 84 Tercel 4wd (aka the pumpkin)
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splatterdog
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Re: water pump to heater core flow direction?

Post by splatterdog »

You need to pay dlb a visit, if he still has a Gates flush gun. It's the next best thing to a new core.
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dlb
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Re: water pump to heater core flow direction?

Post by dlb »

splatterdog wrote: Mon Oct 19, 2020 10:53 am You need to pay dlb a visit, if he still has a Gates flush gun. It's the next best thing to a new core.
I do still have mine. Simon, the next time you drive it out here we can use it on the Tercedes. It's been a while but I remember it being stupid simple -- just disconnect the upper and lower rad hoses, drain the coolant, blast either of the hoses with the flush gun for a minute and see what comes out, reconnect stuff and put new coolant in. SD, please correct me if I'm missing a step there.
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splatterdog
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Re: water pump to heater core flow direction?

Post by splatterdog »

dlb wrote: Mon Oct 19, 2020 2:16 pm
splatterdog wrote: Mon Oct 19, 2020 10:53 am You need to pay dlb a visit, if he still has a Gates flush gun. It's the next best thing to a new core.
I do still have mine. Simon, the next time you drive it out here we can use it on the Tercedes. It's been a while but I remember it being stupid simple -- just disconnect the upper and lower rad hoses, drain the coolant, blast either of the hoses with the flush gun for a minute and see what comes out, reconnect stuff and put new coolant in. SD, please correct me if I'm missing a step there.
It is best to disconnect and isolate the flushing so debris isn't just moved around- core, engine, rad all individually. Just heater hoses if heat is the only objective. I also like to let it run a while for the old and/or nasty ones. I do reverse it at least a couple time also, but starting against regular flow.
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