Is there an easy way to turn the heat off?

[Junkman]

I pulled the push button part of the climate control in both cars and forgot that the default is to full heat. My spouse drives the car (84 & 85SD) and reminded me that it is getting warm and that she'd prefer to have the heat off.

Is there an easy fix that won't take time away from the other projects? I suppose that I could look up the routing and plug or reroute the hose to the heater core. Is there anything easier?

[vstech]

get a hose pinch tool, and pinch the heater hose.

[sleepstar]

use a jumper wire to ground the monovalve

[funola]

Originally Posted by sleepstar

use a jumper wire to ground the monovalve

That may not work since +12 to the monovalve is supplied by the PBU. You can unplug the connector and supply +12 and ground to the monovalve.

[BillGrissom]

I 2nd block the hose off. Where it comes out of the rear head, beside the oil filter is the easiest place on my 300D's. You can also re-route the hoses to bypass the heater core fairly easy, which is a temp fix for a leaking heater core.

[sleepstar]

Originally Posted by funola

That may not work since +12 to the monovalve is supplied by the PBU. You can unplug the connector and supply +12 and ground to the monovalve.

ah you're right, you'd probably need to do both. which i think is still easier than rerouting hoses or plugging things up

[Dan Stokes]

If you have a set of Vise-Grip sheet metal pliers (they have about 3" flat jaws) just clamp a hose - done. The flat jaws won't hurt the hose and are wide enough to fully squeeze the hose shut - piece o' cake. I use mine all the time for that - and they double as a mini sheet metal brake when needed.

Dan

[97 SL320]

On many cars I've used:

3/8" pipe thread brass ball valve ( the 1/4 turn lever type )

6" to 7" long black 3/8" pipe

Cut pipe in half, thread into valve ( use pipe sealer ) Cut supply side of heater hose, install valve. The 3/8" pipe is a tight fit on 5/8" hose and clamps can squeeze 3/4" hose down a bit. For metric you are on your own.

On a MB, the heater valve defaults to open when the engine is off, this lets hot water thermo siphon into the heater core causing the cabin to heat up. Adding a valve would reduce hot soak.

Some other brands of cars don't have a heater valve and rely on air duct flaps to keep the heat out. This cause a problem since the flaps always leak air and the hot heater core in the car will radiate heat. Adding a valve to a non valve car is the next best thing to having AC.

[Dan Stokes]

Originally Posted by 97 SL320

On many cars I've used:

3/8" pipe thread brass ball valve ( the 1/4 turn lever type )

6" to 7" long black 3/8" pipe

Cut pipe in half, thread into valve ( use pipe sealer ) Cut supply side of heater hose, install valve. The 3/8" pipe is a tight fit on 5/8" hose and clamps can squeeze 3/4" hose down a bit. For metric you are on your own.

.

I agree but didn't suggest this as he was asking for something quick and dirty so I gave him the "quick valve" option. Either will get the job done.

Dan

[MB300Dave]

Good advice, brought home an 83 SD that has this heat on problem, thanks, Dave