SPHELL

Just last night my multipoint EA sprung a leak in the heater hose on the inlet side of the heater core. I was around at a mate's place when it happened and he also owns an EA so we checked out his car and found that he was missing a few bits and pieces. His car was missing the water valve and the second hose that connects to the inlet side of the heater core. All he had was a straight hose running out of the thermostat housing straight into the heater core. The inline water valve was missing and the vaccume line that normally connects to the water valve was just sitting there loose.

We ended up fixing my car the same way as his (just ran a straight pipe with no water valve). Everything seems to be ok, the heater still works fine. But I can't help wondering why the water valve was there if it serves no specific purpose. What is it for exactly and do I really need it?

The only thing I can think of is that it keeps the coolant out of the heater core until the heater is switched on????

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Yeah, that is what it does. Also, the water tap is controlled by either a heat switch ( normal a/c system) or the climate control coolant sensor. These will not allow the water tap to open until the engine has reached normal opearting temperature.

If you remove this valve the engine might take a little longer to heat up. It shouldn't really damage the engine in any way though.

Actually, having fresh coolant running through the heater core might be a good thing, because these heater cores tend to start leaking due to the build up of corrosion from not being used enough. I try to run my heater at least once a week to open up the water tap and let coolant run through it for a while.

galapogos01

it also effects the performance of your AC because theres 95degree water sitting a few cm away from the evaporator..

Cobra188

Yeah it's good in winter but you will kill your A/C in summer - put a new tap on before then.