My 300D will shut off sometimes after a long ride and running after the key is off for several minutes if it decides to shutdown at all.
Also it has no warm air in below freezing temps.
It is my daily driver and I run it 140 miles daily.
Is it a mono valve problem or is vacuum connected to the no heat problem?
I am freezing and tired of popping the hood.
Were do I start?

Shut off is almost certainly vacuum related. Will it shut off if you turn the climate control off by pushing the far right button? If so, it tells you you have a vacuum leak in the climate control system. Also try unplugging your monovalve. No 12volts=full heat.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Excluding blower and blend door/vent output.

Rule of thumb no heat:
89% of the time it is the mono valve diaphragm...
9% it is low coolant.
2% it is other issues...

0008350644 MONO VALVE REPAIR KIT, SPECIAL

To begin the vacuum/shutdown diagnosis:

#1. Disconnect and cap off everything except the BROWN vacuum line from the bulkhead/fire wall to the barbs on the large black plastic line. Note: The large black plastic line goes from the vacuum pump to the brake booster.

#2. Start the engine, and try turning it off = does it shut off fast? if yes go to step #4.

#3. If it is still slow = bad Shut Off Valve - At Injection Pump, vacuum shutoff valve at steering lock/key, vacuum pump, and/or brake booster.

#4. If the shutdown is FAST = for further diagnosis you need a vacuum pump.

Here is a cheap one.
http://www.harborfreight.com/brake-bleeder-and-vacuum-pump-kit-92474.html

FYI: Free vacuum pump for testing.
http://www.peachparts.com/shopforum/showthread.php?t=88008

You need to isolate each system = work exclusively on one system at a time.

* You need to disconnect the central locking, and plug it off = the large yellow three way valve at the fire wall.

* Disconnect and cap off the Climate control vacuum feed = the GREEN vacuum line entering the bulkhead/fire wall.

* Disconnect and cap off the egr.

* Disconnect and cap off the transmission modulator supply line.

For more system diagnostic data look through these links.

Climate Control:
http://www.peachparts.com/shopforum/showthread.php?t=142408

"Hen's tooth" 1985 300D vacuum filter dark black
http://www.peachparts.com/shopforum/showthread.php?t=163455

Vacuum Diagrams
http://www.peachparts.com/shopforum/showthread.php?t=105297



.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

you need a vacuum tester or else you need to take it to the shop. its got at least 1 leak, probly more.

__________________
1984 300TD "MAX" 303K+ still going...
fast '70 Chevelle 200k+
home built Shovelhead chopper