Dr ZEE

Guys, from what I see as it's on my '96 ... that valve is "CLOSED" if upper lever of the climate control is in "OFF" position or if the lower lever (Temperature Control) is all the way left to COOL. If I move the temperature lever to the right to about 3rd-4th blue square (dot) ...- the valve OPENS.
So, I gues.... if the valve is removed and the hoses from the pump and to the thermostat are directly connected to the core , then the "coldest" air I could have would be the same as I get now at 4th blue square Well it's not really cold, but not hot either... it's kind of "room temperature" I'd say. However, on the hot day this may be a problem...I don't know. To me this would be really the last option.
Having "normally" leaking a bit here and a bit there valve is unacceptable to me ...heh heh ...so I gotta get to the bottom of this, I hope.
So far - second day no leak here.
Also I dusted-off around the water pump and now I see for sure that I have red RTV gasket there. Attaching picture. So I guess that's where the pieces in the coolant came from.

Dr ZEE

OK, guys, here's an important "update" ....
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So this morning I've started engine (the valve was "closed" / upper lever of the climate control was "OFF") ,.
I opened the hood right away, checked - no leak. I went back quickly and turned the controll to "HEAT and temperature to "HOT", got out - looked at the valve - it's open (lever "UP") and here we go again - LEAKS!!!!
Now it was not leaking too badly, I'd say somewhat 4-5 drops, then slowed down and actually stopped leaking, and then as the engine was warming up it did not leak at all.
Well, so one thing is that it proves my previous "theory" wrong. So I guess restriction of flow in the core does not play role here. Also , then I've got a simple "idea" to sort of "test" that "theory"..while the engine running and coolant is flowing through the core (valve is open) , I simply sqeezed one and then the other hoses between valve and the core , so this should "immulate" clugged core - and this did not make the valve leak, not a drop.
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So I had to come out with a diffrent "theory" here arghhhhhh , I guess.
Well, I don't have any theory really, except that since the leak is minor/temporary and it seems to happen when the valve/hoses/coolant are cold, so I though that what ever "seal" design is inside of that valve/lever - it does not provide good seal untill it warms up a bit and so (theoretically) inside parts and the housing do expand and then it seals well and so stops leaking.

So first I've decided to simply get the valve out again, and take a look at it (how it is constructed inside), I thought if I brake it - then I'll get new one.
BUT! apparently, you can actually disassemble the unit and get the seal o-ring out. There are pair of screws on the unit, those are mounting the vacuum actuator part. If you remove the screw, you can remove the actuator and then you can remove the washer and the rubber o-ring, that is under the washer.

So while I was doing all this I've took my cam and made some photos, and it's much easier to put together series of pics with comments, that describing all this stuff.
So I am going to post all the pics I've made and that will tell the story and I will show what exactly I did, that I (STILL!!) hope maybe will "fix" the problem.
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will post the pictures and comment in a few minutes...

Dr ZEE

first remove the screw and remove the actuator

Dr ZEE

next
remove the washer and then the o-ring.

Dr ZEE

here are close up photos
as you see that o-ring has speacual shape (not like regular kind).
also here's the photo of the original washer and the second washer that I've found (almost the same size), and I am going to add that second washer on top of the original, to provide extra pressure down onto the o-ring, so I hope this will expand the o-ring a bit and provide better seal.

Dr ZEE

in addition I've decided to stuff in some sort of sealant. Well, I really have no clue what could be used for this, so I am just experimenting here and will see how it goes. I had a can of plumber multi-purpose thread sealant, and that's what I used (it's a nasty sticky stuff, that I believe never dries ).

Dr ZEE

Next I 've put some nice amount of lithium grease on the o-ring, placed it on and pressed it down.
Next placed the original washer and on top of it the second washer.

Dr ZEE

Placed the actuator and tighten the screws.
Now with this extra washer, the actuator mount actually presses down onto the o-ring, and you can see a bit of arch (see pic). (note, you don't want to have too thick washer, as I'd imagine, that plastic may crack as you tighten the screws.

Mike1998XJ

Just out of curiosity... How does the coolant in the system look? Does the coolant in the overflow look good? Where I'm going is... could the valve have sediment getting into it that causes it to leak? Maybe it slows the flow through the valve and the fluid seeks the path of least resistance.
Sorry if you already may have said this in a previous thread.
How many psi cap do you have?
Mike

Dr ZEE

OK, to illustrate what I was hopong to achieve here I've made this diagram, that hopefully makes sense ...heh heh
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I have to see how it will perform over the time again. If it'll fail - well...what'cha gonna do - sing blues , what else ?
So far - looks good, but I've been there before, have not I?

I'll post update later if any news.

Mike1998XJ

When I look at yhe new setup I can't help but think that maybe a .010" or .015" shim might be more in order. Nice test and nice sketch though.

I just wonder if we are treating the symptom and not correcting the root cause?
Mike

Dr ZEE

The cap is 16psi. I've just replaced the radiator (manth ago or so), but when I did it, I didn't care to flush the core, so some stuff was still there, some particles may still be in the engine as well , I assume. Now I think I've washed the most of crap out of the heater core.
The coolant in the reservoir is clean, well, except for few micro crumbs of dark stuff there to be exact.

Mike1998XJ

The process to flush the core out is to do it from the longer hose first then back flush through the shorter hose. I went through this process 3 times with my 99'. I'd get good heat for awhile then nothing...
For some reason the particles liked to be trapped in there. Do you suppose the particles could lead to the leak?

Is the domed "look" of the housing due to the extra washer?

Mike

Dr ZEE

Mike, when I flushed the core, I did it one way then the other and then actually one more time both ways. I didn't really have too much crap in there. The water first was a bit grayish, then got clear and I had few red gasket pieces as I've showed.
That what I thought first. I thought that maybe a bit too much pressure due to clugged core makes the valve's seal fail, but from what I experince here it does not look like it. Again, while the engine running and coolant running through the valve/core/valve/to engine I sqeezed and held the core hoses tight and this did not make the valve's seal to fail. Maybe I don't understand something here.
As for now, I think that the reason why it leaks is simply because it's not "perfect" design. That o-ring is not too tight there. But then again, the lever should be turning, so it can't be too tight.
So as for this last experiment, I hope that the combination of a bit "extra pressure" on the o-ring and extra sealant inside will do the trick to prevent the coolant from leaking through when the valve is cold.
Also, keep in mind, that this is the NEW valve I am dealing here with. I'd imagine that an old valve in addition may have that o-ring in bad shape.
I also think that a different o-ring can be used...maybe.

I'll report about how it goes over the time.

Mike1998XJ

Sounds good.
Mike