Hello all,

I am looking at putting my heater core constantly into the loop and not using the bypass valve. So a hose from radiator to heater core, then from the heater core right into the engine. Any downside to this other than losing the AC option? I do not have that right now so its a moot point at the moment. Also, the heater core has been disconnected for some time, with both openings exposed....if I just hook up one hose then run water through by gravity through the hose should that wash out anything of issue?

Thanks guys...

 

Did you dissconnect the heater core your self?
If not it could have been by passed because it was leaking.
As long you are running some kind of coolant by pass you will be all set.
Try washing the heater core out with a garden hose so you get all the dirt.

 

Only downside to not having the Heater Diverter Valve aka "bypass" is that you'll have warm coolant circulating through the heater core (and thus through the cabin) at all times, which will warm up the interior slightly when you least want it (like July). But if your A/C isn't working anyway, in July you're running your 2.2.60 A/C anyway (2 windows down, 2 t-tops out, 60mph), and you'll never notice. Mine's been out for over 3 years now.

Like mentioned, I wouldn't hook up the heater core though without replacing it FIRST - the only reason anyone disconnects it is because it's leaking, making a mess in the passenger floorboard and overheatig the car!

 

No I didn't disconnect it myself, but the previous owner was turning the car into a drag racer and took out the entire HVAC console and stuff, so I am sure that's why he bypassed it. However I am ware the core could be bad, but one step at a time right?

And I am actually asking if I can do it without a coolant bypass at all, essentially constantly running coolant in the heater core., solid line from radiator to core, then core to engine, is there a reason this would not work? I know the core could crack from sudden temp changes but I would assume they will be gradual in general as it will be same temp of coolant that the engine is using since its in a system.

 

Hmm, for the 28 bucks maybe I will just preemptively if nothing else....thanks.

 

according to the great people here. the only time the valve diverts coolant is when the a/c is on. other than then it always flows coolant. i am about to remove mine.

 

If you think the heater core is good, then test it with water like mentioned - spray the garden hose into it and check the pass floorboards for leaks - at least then a leak found is only water. Replacing it isn't expensive, it is a PITA though - you can do it from underneath the pass dash, but there's one or two little screwheads that you can't see, and you can barely feel - so you need a 1/4 rachet, some extensions, maybe a swivel, a 7mm socket, and ALOT of patience, but it didn't take me more than 2 hours to do it the first time, and that was mostly spent resting my arms from the cramps I got from being in weird positions trying to get those last screws!

 

Yes you can run the heater core hot all the time.
I do, but I have a Heat and AC system where it uses a little door to block air flow to the heater core.

 

Thanks guys, since its 26 years old I think I will just replace it, and deal with the hassle now. For 28 bucks I can't complain too much.

 

I did something similar with my car that you might want to consider. I dont have the factory diverter valve but in it's place I have a standard brass valve that I can open and close manually. That way in the summer I can take the heater core out of loop and leave it in the rest of the year. This valve is also conveninent if your heater core happens to spring a leak while you are driving thus dripping hot antifreeze all over your feet (Don't ask). But you are right, it is definately worth the cost to go ahead and replace the core now. Hope this helps.

 

I also did not have a diverter valve like 88gta_hiflyer, so also installed manual shutoff valve(s). I put a shutoff in each hose. Then in the summer, I turn them off to stop hot antifreeze from going thru the heater core. But then I pull the hoses off the valves and hook them end to end using a 5/8 to 3/4 hose adaptor I picked up at Parts America. This keeps more antifreeze flowing for cooling. When you stop, then heater core does pick up heat from the engine but it will go away after a few miles of driving and the heat in the summer is gone.

 

Hey hiflyer, I am looking to do the same thing to my 88. It has an engine swap to carb and the heater core is disconnected. I already bought a new core and am getting ready to put it in. The intake manifold just has a plug in it where the connector for the heater hose should be. The inlet on the radiator is capped.

1. Can I buy a shut off valve that will fit directly into my intake manifold (what size threads?) or do I need to get the standard type connector from an autoparts store and get a shutoff valve that will splice into the hose?

2. Do I need shutoff valves for both the feed and return lines of the heater core?

3. Can you post a picture of your setup?

Thanks for your help.

 

I can't remeber exactly how it's set up right now but I'll check it out when I get home from work tonight. I've never posted pics on here before but I'll definately give it a shot. As far as the valve coming directly out of the manifold the only problem I can see is clearance issues. There isn't much room there (at least with a stock setup) and that hose has to make a relatively short 90 degree turn.

 

For me I have plenty of room. They do have 90 degree brass fittings too if I need one. Uploading a pic is easy. After clicking reply, then click Go Advanced button, then Manage Attachments, then Browse to select the pic from your computer, then upload. Do you have shutoffs for both hoses?

 

This is what I have now. The first pic is the intake manifold with a plug in it.

The second pic is a cap on the radiator return.

 

The first pic is the heater core with the feed port (I believe) with nothing attached. The return port goes to the metal piping that runs down the side (I don't know what it is called).

The second pic is the piping with nothing attached. It's kind of rusty so I will probably just run hose the whole length and remove the piping.

 

Alright here is what I've got. It works but it looks kind of bad. I actually just got a stock diverter valve from the junk yard that I will be swapping in.

 

I can see what you mean about having tons of room up front on your setup. It might work out well to put your valve in the line coming out of the intake manifold. As far as the thread size goes, I'd take the plug out and take it with you. One suggestion though, if you use brass valves like I've got spray them with some clear coat out of a rattle can. Otherwise they get that green corrosion on them quickly and they look like crap.

 

I was thinking more along the line of a small inline shutoff. I don't like the turning green part at all. I'm not so sure I want to go that route after seeing what it did on your car. Maybe I can find something in stainless. Thanks for the help.

 

Yeah I don't like the way it looks either. It took me forever to find a stock diverter valve but I finally got one and it's going in this week. The stock valve is the best looking option I've seen but I'd be curious to see what you come up with.

 

I'll let you know. If I can't find a good solution I will be looking for the stock valve also. I would have to run new vacuum lines to use it though.

 

Downside is your interior is going to be hotter.

 

Hey hiflyer, this is what I ended up with.

Pic 1 shows line from intake manifold.

Pic 2 shows shutoff valve in winter position. It hidden pretty good.

 

And pics showing valve in summer position.

 

That looks good. You did a good job hiding the valves. I just installed my stock diverter valve a couple days ago. With the emmissions stuff gone it actually looks pretty clean and is out of the way. I had to re-route some vac lines but it works perfectly.