Wondering if anyone has installed a heater control valve in the fiero? A valve to stop the flow of coolant through the heater core.

I have a non A/C car, though I think it still applies to an extent to A/C cars also. When I have my HVAC controls set to vent, I still have heat leaking out. I assume that the seals around the diverter door needs to be replaced. But even with that done there is still hot coolant running through the heater core. Since I don't have A/C I want to make sure all the air entering the car is as cool as it can be, and during the summer I have no need for the heater. It looks like a lot (most?) cars have a valve to cut the flow to the heater core. Some are vacuum controlled, some are cable, and some are electric.

Here's a picture of a retrofit kit for vintage cars:

ebay link
Could be fun to hook into the electronic and control the flow with a cabin thermostat. Sodo climate control.

I don't need anything quite as sophisticated as that. I'm going to browse the scrape yard and see what I can find out of another car. I'm going to be of course looking for an electric one. From looking around ebay and such it shouldn't be too difficult to find. There is always the option of just buying a 12v valve also, like this one.

Wondering if it has been done before.

The question is, can the Fiero cooling system deal with being "dead ended" with one of these valves, or would it cause problems... It would be like sticking a cork in the end of the supply / pressure hose. Some cars have "Y" type diverter valves, where the supply would come into the base of the Y, then it gets directed into either of the outputs depending on position. One output of the Y would go to the heater core, the other back to the return hose. Output of the heater core would go back to the return hose as well.

When the heater core Y output is "on", you get full heat. When the "loop" Y output is "on", you'd get no heat. In between = varying heat, but in the Fiero's case that wouldn't really be needed. No idea what cars to look for with that type of valve, but I have seen them. It may not matter, and just plugging the thing may work. But worth checking into on how the system flows first..

In the Fiero cooling system the heater loop is the only thermostat bypass, so there must be free flow at all times. A simple on/off valve will not work. What is needed is a two-way (four-port) valve to direct water flow either through the heater core or bypass the flow around it.

Otherwise, this is a good idea. I don't like a hot heater core during the summer, either.

[This message has been edited by Marvin McInnis (edited 06-15-2012).]

That valve will NOT work on most cars, inducing Fiero.

Car need bypass flow that heater provides.
The valve likely doesn't close all the way shut but also likely doesn't give bypass flow to engine enough to keep Fiero Tstart from collapsing. (See cave, t'stat in cooling section)

Many car came with a valve, similar to above, to kill heater but they also have pluming that deal with valve shut. They has a bypass for the valve and heater, just 1/4" pipe will do...

If Fiero's dampers work right... Heater shouldn't matter where set to cold air. Air is closed off from heater... If air feels hot:
Damper is not working
Intake Air is hot from outside... Sun and hot frame/body can heat air much more than people realizes. Can take awhile for part to cool down.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

[This message has been edited by theogre (edited 05-02-2011).]

FWIW, my old 1980 Porsche 928 had a vacuum-operated heater shutoff valve that closed whenever air conditioning was selected. The 928 engine compartment was tightly packaged, so summer heat management was a big issue. Unfortunately, the vacuum-operated valve was configured to open back up when the engine was stopped, allowing hot water to circulate through the heater core by convection and/or other residual pressure differentials in the system. The result was a seriously heat-soaked cabin whenever you restarted the car on a hot day. It didn't help that the (uninsulated/unshielded) refrigerant lines were routed within several inches of the right bank exhaust manifold.

[This message has been edited by Marvin McInnis (edited 05-03-2011).]

When I first bought my car, the heater core was bypassed. Apparently, it had been leaking, and coming from Florida, a good heater wasn't an issue. They had just put a length of hose between the two hoses under the car directly below where they feed up thru the front trunk. They just bent the hose into a horseshoe shape and stuck it on.

That could be a good place for a functional bypass system.

Jonathan

Yeah I had to bypass my heater core for the same reason (leaking) at one point. Its really easy to do in the front compartment.

As for it working by just plugging the system, I'm not surprised. That's what I had thought. My dad said that I could just block it off. I told him I couldn't because the heater core is the bypass for the thermostat. He wouldn't believe me so I figure I would ask here.

Its not that the air coming out the vents is hot/warm. Its the floor vents that have a very small amount of air coming out of them. But it not so much the very small amount of very hot air coming out of the floor vents, its the fact that the heater causes the the air ducts (not sure if there is a better term) to get hot. I would be interest it someone checking the temperature of the "hot ducts" ( floor ducts) with a perfect seals. I would assume that the actual duct work is hot, and just the radiating heat from that is unwanted heat. Keep in mind this is only true for non A/C cars.

Btw, like you (theogre) have mentioned in the cave if you have air flowing by the heater core slowly the air is heated more then if the air is moving by the heater core quickly. The very small amount of air that leaks past the heater core into to cabin is moving so slowly across the heater core that it makes the air very hot. You also say you haven't seen a non A/C car before, the way the doors work in the A/C cars is different from non A/C cars and it may not be as noticeable on the AC cars. Also keep in mind that non A/C cars can not have cold air vent through the floor vents, only hot air.

Basically like Marvin said above where the heat of the heater core heat soaks the cabin. Therefore causes unnecessary heat in the cabin.

Of course the easy way to bypass the heater core is just a piece of pipe. I am just looking for a little more sophisticated way. I would like to have the bypass electrically controlled out of convenience. In the spring and fall at night it gets cold so the heater does get used a bit during those seasons. Also I would like to be able turn the heat back on encase I need to defog the windshield.

The only thing I can thing of so far is a Y or a T connection with two valves. That might be the only way. A little more piping then I would have liked but might be the only way.

Or I forgot what riceburner mentioned above. If I can find a car with a Y diverter valve that would make it much easier, I think I have seen these on ebay, there is just not much description of the parts. I'll be headed to the scrap yard to see what I can find. If anyone has any idea on which cars to look for an electric Y diverter valve, or a place/website that could give me a little more info, please let me know.

[This message has been edited by bnevets27 (edited 05-02-2011).]

Just an update/FYI. I found this: http://www.ackits.com/merch...60027&Category_Code=

I'm working on ordering it. And will install in when I get it, and try and remember to come back to report the results.

they make a cheap 3 way valve that works on vac. , one of those and a tee could make a bypass loop. thats how my van does it. I think the valve was <$20. you'd have to figure out how to controll you vac source. Seems like it would make more sense to just fix the damper door seal for the work and mess involved...

quote Originally posted by gen2muchwork: they make a cheap 3 way valve that works on vac. , one of those and a tee could make a bypass loop. thats how my van does it. I think the valve was <$20. you'd have to figure out how to controll you vac source. Seems like it would make more sense to just fix the damper door seal for the work and mess involved...

Yeah I found those on rock auto for about $20 and yea they work off vacuum. But then you need a solenoid to control the vacuum also and I wasn't able to find one for cheap, as far as I remember $20-30. So Now I'm at $50-60 and more work... So I just decided on the one above. Fixing the door seal (I really don't think is that bad) doesn't stop the heater core from heat soaking the cabin. Also this will allow me to blow "cold" outside air at my feet.

My '86 GT had a leaking heater core so I temporarily bypassed it connecting the in and out hoses to each other. The connector I used had too small of an opening in it which greatly reduced the flow. This was the result...



Lesson learned.

There are a lot of Dodge cars that have a 4 port heater valve that will bypass the heater.
autozone part number 74701


Patrick,
I have seen that happen to many fieros, I haven't came up with a cause/fix for it yet.

That problem is becoming rampant for that style T-stat, but I don't believe it is caused by pressure or restriction, but rather inferior part quality, they are too tall for the housing and they either smash on install, or after some time the arm just gives out.

I also found that Thermostats that rest IN FLOWING coolant behave FAR more consistently, and accurately. This is the reason the heater core is used as a bypass. NOT for pressure reasons, but so that the coolant is able to travel around the engine then near the thermostat. Otherwise the water around the cylinders would boil, while the thermostat is still sitting in cold non flowing water.



This design failed to function properly with a Fiero's thermostat until I put the 3.4 DOHC's thermostat in its factory place on the intake and removed the one I had in the filler neck. I've never had a single issue with it since.

quote Originally posted by buddycraigg: There are a lot of Dodge cars that have a 4 port heater valve that will bypass the heater. autozone part number 74701 Patrick, I have seen that happen to many fieros, I haven't came up with a cause/fix for it yet.

Yup that's the one I saw. Again tho, need a vac hose and a solenoid to get the same functionally. No harm with that, I just wanted to go with a slightly easier approach.

And I do have a fix for that. I made it myself so it's not something you can go out and buy. And I know I'll get flamed about pressures and whatnot. But I don't care it works well and I don't have to keep buying thermostats that keep collapsing. I'm pretty sure I don't have a pic, so I would have to pull it out of the car I'm currently driving. I'll see if I remember/get around to it. I basically remade the arms or whatever you call them stronger so they don't collapsing. Its a separate piece but that's the idea.

quote Originally posted by buddycraigg: There are a lot of Dodge cars that have a 4 port heater valve that will bypass the heater. autozone part number 74701 Patrick, I have seen that happen to many fieros, I haven't came up with a cause/fix for it yet.

what dodge models/years.. nice to know for thy junkyard crawls

I asked and was told by a Fiero veteran /expert that the cars that did not come with AC will blow somewhat warmer than ambient air even when the sliding selector is set to cool. My 1st 86 basecoupe car was this way. I went to Lowes and got two T fittings, and some shut off ball valves. I got some heater hose and clamps from the auto parts store. I made my own shut off and bypass. I did it under the hood by the jack. I don't think I have any pics and no longer own the car. It worked great.

[This message has been edited by 2.5 (edited 06-07-2012).]

quote Originally posted by 2.5: It worked great.

Awesome! Finally someone confirmed my thoughts. Probably be a little while to get it and install it but should have it done this summer. That's where I plan to put it, with a switch inside so I can switch between bypass and heater core on the fly

[This message has been edited by bnevets27 (edited 06-07-2012).]

I have a 3800 s/c. I put a shutoff on my heater core feed right at the lower intake manifold under the supercharger. It came from a bulldozer lol and threaded into the hole I had tapped to 1/2" NPT. It works great. The cabin is noticeably cooler. I have since installed a/c and I find it still makes quite a difference. My setup didn't have a T-stat bypass to begin with and it did give my some problems so i did the unthinkable and drilled 2 small holes in the T-stat. It does take a while to get the car up to operating temp but once it gets there it holds a nice 190-195*.

DF

quote Originally posted by buddycraigg: Patrick, I have seen that happen to many fieros, I haven't came up with a cause/fix for it yet.

quote Originally posted by Fierobsessed: That problem is becoming rampant for that style T-stat, but I don't believe it is caused by pressure or restriction, but rather inferior part quality, they are too tall for the housing and they either smash on install, or after some time the arm just gives out.

All I can say is that in my own experience, the only time it's ever happened to me (during 14 years of owning several Fieros) was the one time when I greatly restricted the coolant flow through my heater hoses with an unsuitable temporary by-pass connector.

It never happened before and it's never happened since. However, I suspect in some situations that people have had the "arms" bend through improper installation of the thermostat.

Just for future reference, if anyone is interested. ackits.com would not sell to me because I'm Canadian. Action-AC was willing to ship to Canada: http://www.action-ac.com/AC-Part/31-60027.html Also Thermotion will also sell the valve and ship it to Canada. They don't really have a sales website but if you email sales@thermotion.com they will set you up with one. I also assume that they are the actual manufacture of the valve and other companies just put there name on it, seeing as they have the spec sheets. Here's the main page for the valve: http://www.thermotion.com/t...t-control-valve.aspx

Not sure when a thread gets put into archive so I'll make sure I bump this now. I have the valve in hand and plan to have it installed by the time I get the fiero on the road this summer.

...install the 84 vent assembly openings if you need more cool air coming in...I was going to do this to my 86 before I sold it.

[This message has been edited by Mickey_Moose (edited 04-23-2013).]

quote Originally posted by bnevets27: ..., I still have heat leaking out. I assume that the seals around the diverter door needs to be replaced.

i wouldn't worry - the system is designed to "leak" air around the doors inside the big black plastic enclosure.

i like the idea of a heater core diverter, but wonder if the heater core would corrode while coolant flow is blocked off and coolant just sits in there stagnant (?)

quote Originally posted by Mickey_Moose: ...install the 84 vent assembly openings if you need more cool air coming in...I was going to do this to my 86 before I sold it.

Interesting....I'll have to find some more info on that if I can. If for the very least to feed my curiosity as I don't know the difference in the 84 vent assembly openings vs all other years. Though at the end of the day I don't really need more air, lucky to have a sunroof car. Biggest problem is turning the blower on caused a little more heat to find its way into the cabin with the cold air. Well not exactly with the cold air really, I would get hot air ever so slightly leaking out on the foot well vents. Wondered for the longest time why my feet always got hot...

quote Originally posted by PaulJK: i wouldn't worry - the system is designed to "leak" air around the doors inside the big black plastic enclosure. i like the idea of a heater core diverter, but wonder if the heater core would corrode while coolant flow is blocked off and coolant just sits in there stagnant (?)

Was never too worried it was leaking hot air past. If I wasn't putting the diverter on then maybe I would pull it out an investigate but I don't have much reason to now.

Well there's a good chance the diverter is going to be turn on and off relatively often. The nights still get cool for a good portion of the summer up here. So I'll probably will be switching back and forth pretty frequently, add the fact if the window is fogging up I'll want the heat for that too. This is why I wanted it be controllable inside the car, comfort and "safety"

quote Originally posted by PaulJK: i wouldn't worry - the system is designed to "leak" air around the doors inside the big black plastic enclosure. i like the idea of a heater core diverter, but wonder if the heater core would corrode while coolant flow is blocked off and coolant just sits in there stagnant (?)

Under the dash - there are cut outs already there in all the cars, just the 84's had the vents installed with a pull cable just under the steering column to open and close them. GM just deleted the hardware in the later years and capped the stamped out holes in the front 'firewall'.

They are located just inside of where the front speakers are located.

Edit: here is a link, and BTW these are ONLY found on the 84 NON A/C cars.

https://www.fiero.nl/forum/A...120111-1-083259.html

[This message has been edited by Mickey_Moose (edited 04-24-2013).]

quote Originally posted by Mickey_Moose: Under the dash - there are cut outs already there in all the cars, just the 84's had the vents installed with a pull cable just under the steering column to open and close them. GM just deleted the hardware in the later years and capped the stamped out holes in the front 'firewall'. They are located just inside of where the front speakers are located. Edit: here is a link, and BTW these are ONLY found on the 84 NON A/C cars. https://www.fiero.nl/forum/A...120111-1-083259.html

Wow, ok. That's really cool/neat!. I would actually love that, from the sounds of it, it directs the air from the outside down to my feet. Now I have to find a set! Next question though, would I have to remove my dash to install them? I wonder if having aftermarket speakers will prevent them from fitting also, I'm using the adapter to have 5.25" round speakers.

[This message has been edited by bnevets27 (edited 04-25-2013).]

quote Originally posted by bnevets27: Wow, ok. That's really cool/neat!. I would actually love that, from the sounds of it, it directs the air from the outside down to my feet. Now I have to find a set! Next question though, would I have to remove my dash to install them?

...to make it easy yes - but if you are really patient you "might" be able to do it without and only removing the speaker - but that is a really BIG might...

Doesn't take much to remove the dash, I am sure there are threads on here on how to do it.