Vacuum leaks

[James Morse]

Holding vacuum is another test you can do without special tools. With selector to OFF, (engine on) the door is activated; when I turn off the engine it takes 45 seconds before it starts to move. That's the point there's not enough vacuum to keep it open. Then over the next 30 seconds it gradually closes (or opens depending how you look at it).
At least on this model, all you have to do is open up the glove box all the way to test that. Actually it's pretty nice the way they made much of it readily accessible.

That's with the white to the heater valve plugged of course per above. Until I get that done. When it's good, test should act the same.

 

[James Morse]

I got the part from PlumCrazy and it's good. The old one had cracks in it so it was leaking, once I had it out I could see.
I may have an issue with the connector sealing inside (at the firewall under the glove box) but I bypassed that for the moment by running short tubes between them. The heater valve activates properly. But the heater core hoses get hot and they shouldn't.
In its relaxed position the valve should be normally open. It only closes on Off or Max AC. All that works fine as to it being actuated properly.
Heater Control Valve operation and testing - YouTube this vid shows a valve, looks the same, but it's normally closed which would be the opposite of what this one should be.
But I get tons of heat so it couldn't be normally closed either. It there any possibility it's in wrong? It doesn't make sense.

 

[ericbphoto]

Rather than thinking of it as closed or open, think of it as “heat” or “bypass”.


The valve in one position (heat) sends hot coolant through the heater core. In the other position (bypass) it bypasses the heater core. The bypass position would be for “off” or “max A/C.

Coolant always passes through the valve following one path or the other.

 

[James Morse]

I feel kind of dumb, but, I think it's working. I see it being actuated properly in those two settings as you say. I think there's probably a little bit still coming through when it's on bypass.

In the pic the right hand hose from the engine has to be the "in" side. When it's on "heat" it's allowing coolant to the right hand heater core hose, as you look at the pic.

When the engine is pretty warm with a thermometer I measure 155F on the outside of the hose from the engine, and about 125-130 at both the heater hose so that's quite a differential. If I set it to heater the core hose rapidly gets to 155 and with the fan on you see a significant differential for the "out" side of the core and at the return hose for the engine.

So that just seems like everything is working as well as it's supposed to work and I think there's just a little heat that still gets to the core but if you were driving and/or had air going through it for A/C it probably would be a pretty insiginifican't amount of heat actually getting in there.

Will chase connectors at firewall another time. Since everything works properly afaik if there's any possible issues that's the last place.

 

[ericbphoto]

Sounds like it’s working fine. Good job.