Need a lot more heat.

[Jack M]

HI All,

Well it’s 40 degrees in Los Angeles and I need some heat. I have an ‘86 560. Would some one give me a run through of how the mono valve works and what triggers it to open. And where does the hot water go?

How can this system be tested? Or diagnosed to what may not be working.

Thanks, Jack

[Gilly]

Let me give you a quick tip.
Assuming you see the water valve, disconnect the wire and remove the 4 slotted screws (make sure pressure is relieved, either a cold engine or remove the pressure cap from the tank),
Then pull up the valve "guts" (by the shiny part inthe center), you will see the rubber diaphragm, make sure it isn't ripped. I will try to find a picture online of what it looks like if it's ripped.
If it is you buy a repair kit.

Link to thread here showing bad diaphragms (whole thread worthy of your review):
Damaged mono valve pictures please

[Jack M]

Hi Gilly
I have a spare water valve. When I look in the opening and view the Monovalve when I apply 12vdc the valve moves up about 1/8 to 3/16 of an inch. Is this enough?

If the monovalve has deteriorated and water flows through it, does that hot water go to the heater core and give you heat. ( meaning that you would get heat all the time?

If the valve is down (good monovalve) then you get no hot water which means that the AC would not be fighting the heat ?
When should it be running?

Thanks, Jack