OT auto repair OT

[Tony Hwang]

Tank is full? Try new rad. cap with proper pressure rating.

[Mr.E]

Try removing the heater hoses from their system connections and flush GENTLY in the reverse direction to normal in/out. I had a similar problem on a Mazda and a large piece of cloth flushed out of the supply hose. It would not go past the on/off valve so the reverse flush pushed it out the hose.

[makolber]

that does seem to indicate a water flow problem through the core.

did you flush the core in the __reverse__ direction?

does a bunch of crud come out? you may have a really plugged core

is there a bypass path where the water can flow "around the core"

Ford Taurus had such a system and even a small restriction in the core would casue the majority of the water to flow through the bypass..

Mark

[DerbyDad03]

Here's an interesting factoid that most people will never need, but it might make an interesting (not really) automotive trivia question:

How can you tell that the cabin air filter in a 1999-2004 Honda Odyssey has *never* been changed?

I don't know if this is true for any other vehicles, but on the 2nd generation Honda Odyssey, there is a plastic support bar that has to literally be *cut* out of the vehicle in order to change the cabin air filter the first time.

In order to keep the dash from flexing during installation at the factory, there is a plastic support bar that connects the right hand side of the dash to the center. The bar is only there to make it easier to install the dash. However, once the dash is installed, this bar blocks access to the panel that covers the cabin air filter housing.

The neatest way to remove the support is with a Dremel, but people have used diagonal cutters, utility knifes, etc.

[Stormin Mormon]

I'm all aquivver. I'm so excited, I can't sit still.

[clare]

Not sure about your year, but many earlier 4-runners had a problem with the water control valve. The control shaft pulled out of the "spool valve" that controls the water flow - moving the shaft opens a roughly 1/4 inch hole instead of the 5/8" hole it is supposed to open.

I replaced a few dozen of those (and on some other Toyotas as well) Remove the valve and check it carefully.

[Terry Coombs]

Valve has been removed and checked , I get full range of motion and it stays put on the shaft . On the blend door thing , I'm observing the levers and stuff on the top of the heater outlet , all seems to be working properly . I can actually hear the doors inside moving when I move the control lever .

[Terry Coombs]

Answered above (or below) , the hoses are both very hot when it works right , in is hot and out is not as hot when it's malfunctioning . That indicates to me that there is not enough flow thru the core .

[Terry Coombs]

I've flushed the core both directions , good flow and no indication of any obsbtruction .

[Terry Coombs]

Flushed both directions , only thing that came out was a little rust in the water . No chunks or particles of any kind were flushed out - also flushed the engine block , same result , some rusty coolant then clear .

[DerbyDad03]

Plan B:

[Terry Coombs]

That's spelled "last resort" ... not plan B .

[dpb]

On 10/30/2015 2:31 PM, Terry Coombs wrote: ...

But you say this is intermittent--works sometimes but not others?

[Terry Coombs]

It will work fine sometimes for a few minutes or a couple of hours and maybe even a whole day or two after I fiddle with it . It did seem to come back when we were driving around town today , but who knows , it's warm enough without heat today .

[dpb]

Makes me suspect a loose obstruction hanging up or perhaps the controls are intermittent themselves?

That was a biggie with one of the series of Chebby pickumups in '97 or thereabouts...the dampers are electric motors and combined with their tendency to lock up and then burnout the motor the actual control circuitry was subject to a service bulletin that wasn't a recall but if the customer complained they'd swap it out...

[clare]

Whatever is happening is intermittent. I HAVE seen the heater valves appear to be good when looked at, when the heat is working. The trick is to remove the valve when the heat is NOT working and confirm.

[Ed Pawlowski]

Could be a piece of crud floating around? Partly blocks the water, then floats a bit and opens the passage for good flow?

[Terry Coombs]

That's about the only explanation I can come up with too . I just can't figure out where/what it is and how to get it out .

[Tony Hwang]

Flushed the system proper B4 filling up?

[bob haller]

its best to run water both directions thru the heater core, and pulse compressed air thru the heater core at the same time, replacing all the coolant with plain water, then drain, and replace all the coolant with a 50 /50 mixture of NEW coolant