Is the valve supposed to bleed off vacuum after actuating for shutoff? The new switch in our '79 does this, and works properly, but I can't remember if it did that when I put it in last year. I discovered this chasing an intermittent no shut off problem. Fixed that with a new piece of vacuum connector hose on the shutoff valve side of the ignition switch.

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k

It should bleed off vacuum when the ignition switch is turned to 'on' I think.

__________________
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

What kerry said. A tight system will hold vacuum for days or until you turn the key. The shutoff actuator should hold vacuum indefinitely. With the key in the off position, the system should hold vacuum all the way to the fitting on the brake booster vacuum line.

Sixto
87 300D

Thanks you, gents! I think that confirms the second part of the diagnosis, that the ignition switch is leaking. As noted by the oil I found on it today, along with one weak vacuum connector on the line going to the shutoff valve.

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k

I hate to be the bearer of bad news but...

If your ignition switch is leaking oil then your vacuum pump needs attention. Oil is getting into the vacuum system from a leak in the vacuum pump.

The oil eats diaphragms in the actuators. You most likely have oil all up in your door lock and climate control system as well (and you have the evil servo in your '79 which makes it worse). And your power brake booster too. Yuck.

When you get it all fixed many people install a clear mini fuel filter (like for a weed whacker) in the small vacuum line going from the engine to the accessories so that if the oil problem comes back you know about it.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I would think oil in the key switch comes from a leaky shutoff actuator. A leaky vacuum pump would have to turn into a pressure pump to push oil all the way to the key switch.

Sixto
87 300D

Could also be a hole in the vacuum shutoff diaphragm.

__________________
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

Yes I wasn't thinking right on that. The oil could well be coming from the shutoff.

However it does not hurt to inspect the vp on that old of an engine anyway...

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Good points, I didn't want the less than one year old shutoff valve be the culprit, but I do believe it's holed, as it won't hold vacuum for but 2 seconds when isolated and tested. The switch won't either, but the rest of the system is tight. The evil servo had been bypassed with the crude but effective cable by the previous owner. I haven't had the desire to dig into that at all.

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k

Those shut off valves are a bit on the pricy side for what they are.
If you use a Mity-Vac or decide to suck on a Vac Hose connected to the shut off nipple, be sure to use a piece of clear tubing. this way you will see if there is oil in the valve, and keep the oil out of your mouth of vac pump.

Once removed, pushing in the lever in and holding your finger on the nipple, it should hold the lever in. If it starts to work it`s way back out, then it is bad.

Note: Be sure to hold the Nipple away from your body incase the valve is full of oil when pushing in on the lever. I pulled one at PNP and it shot oil 4ft.


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Thanks Charlie, and they are way expensive for what they are. I found them cheaper, but still pricey somewhere on the wide wide world of web. I have it posted in another thread, but it was $55 or $60, and mis-named as a shutoff solenoid.

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k

Yes, the prices for a shut off actuator have sky rocketed.

The actuator itself is the problem, not the vac pump.

__________________
83 SD

84 CD

When you are in PNP be sure to remove them. 4 10mm bolts, and it is yours. I found a couple that were new.

Sucks when I finally get one off and it blows oil.

I think some of those $50 and $60 etc... one`s are Chicom one`s. saw ne that was a MTC brand for cheap. the Bosch one`s are around $167 + -.
you are right........they are pricy for what they are.


Be nice if it was made to add a Choke Cable. My Datsun Diesel had a rod and electric motor to kill the engine. thing crapped out, and is/was pricy, so added a Choke Cable, works everytime.


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

The cheaper one I found on fcp's site was made in India. Here's the link:

http://www.peachparts.com/shopforum/diesel-discussion/317246-w123-fuel-shutoff-valve-source.html

Unless there's some sort of counterfeiting going on there.

Edit: The price on that site is $110 as of today, twice what it was.

__________________
1985 300D-189k The 'UD', Ivory and Pinkamino
1979 300D-211k Dark Gray, Parchment
A 1980 Harley-~166k and
A 1994 Ford diesel pickup-349k and
A 1990 gasser Volvo wagon-145k

FCP lists that MTC one on 2 different pages, one for $60.60, and one for $110.95, and the Bosch for $167.95.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works