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  #1  
Old 09-27-2003, 06:48 PM
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Where does the oil in the vaccum line come from?

i posted this in the tech help section also, maybey its only a diesel problem, i am new to this.
1980 300 td with a later model engine and turbo, i think it said 617. somthing on the block
after doing many searches i could not find the answer
so here is the problem, oil in all ACC vacuum lines, oil in vaccum line at the ignition, but not at the fuel shut off valve, no oil in brake booster line, locks just recently stoped working, engine shuts off slowly( but i by passed the ignition and it shuts off quick) no suction to the black line that turns on the heater valve. wher does this oil come from and what do i need to do to fix it?
i inspected the vacuum pump and could only find one line coming out of it, it is on the top about 1/4 inch and metal, i figure this line does the suction, so if the pump is bad where does the oil come from.
any help or suggestions on what to look for would be great. thanks
lc

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Old 09-28-2003, 12:19 AM
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Don't quote me on this but I'm pretty sure when the oil starts feeding back into the system that your vacuum pump is nearly failed (when it does completely it could possibly take the motor with it!). One popular upgrade is sticking an inline fuel filter in the vacuum line before the vacuum system going into the passenger compartment because it can get nasty if to much oil gets in there, also it lets you know if the oil is trying to get in so you know that you need to get working on the vacuum pump ASAP. Yes that metal line is the vacuum line, it goes to the commonly brittle plastic hose that the lines feed off of as well as the brake booster. Have you checked how much vacuum it is pulling? I believe it should be in the vicinity of 17-22"hg.
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  #3  
Old 09-28-2003, 02:02 PM
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A bad diaphragm in the vacuum pump would lead to the symptoms you describe. Another indicator of a faulty diaphragm is the appearance of oil in the air filter housing as well as in the hose that runs from the vacuum pump to the air filter housing.

It’s an easy job to replace the diaphragm once you get the pump out. Unfortunately, it’s a mojor PITA to get the pump out. Good luck.
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Old 09-28-2003, 02:25 PM
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thank you for all of the help, here is the thing, i dont have a line going to the air filter housing, i have the piston style pump with one suction line coming from the top, i just bought a mighty vac this morning and the vacuum pulls 20 and the mercurey scale. let me give some back ground, i bought this car from a mechanic on a lean sale, they put in a "rebuilt engine" and a new factory rebuilt transmission, i trusted the engine had been rebuilt because the transmission was spotless, not one spec of road grime, you know the look that can only be acheived by soaking the case in solvent. any way here is my thought, the old vac pump was bad sucked oil into all of the lines, after they put the new engine in it sat for a while letting all of teh oil in the lines settle and now it is being sucked into the vacuum. what do you think?
thank you for you time, this is great to know people are willing to help
william
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  #5  
Old 09-28-2003, 03:29 PM
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Two possibilities here:

1: Bad vac pump AND bad check valves. Allows oil into the pump, where it gets sucked into the main vac line due to bad check valve.

2: Busted diaphram in the shutoff servo -- oil from the IP is dragged back through the keyswitch and into everything else.

I'd suspect a bad vac pump, but the way to check is to get a MitiVac and see what kind of vacuum you get. You can also use the MitiVac to check the integrity of the rest of the vac system.

you need to get the oil out if you can, it eats rubber parts.

Peter
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  #6  
Old 09-28-2003, 05:07 PM
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injection pump is good, tested with line straight fom vac pump, and there was no oil in the line, also checked vacuum at the pump it read about 20 Hg
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  #7  
Old 09-28-2003, 05:08 PM
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sorry i meant shut off servo is good instead of injection pump
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Old 09-28-2003, 05:42 PM
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PO rebuilt pump or replaced servo, and the oil has been migrating around since.

Peter
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1988 300E 200,012
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1985 Volvo 740 GLE Turobodiesel 218,000
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  #9  
Old 09-28-2003, 07:49 PM
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i was hoping some one would say that! that is kinda good news right? this means i can suck some kind of cleaner( soapy water?) through all the vacuum lines and try to clean it.
do you think that is a good idea?
thanks to all
william
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  #10  
Old 09-28-2003, 08:12 PM
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Brake parts cleaner will work better. Replace all the softened rubber connnectors while you're at it.

Peter
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1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
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  #11  
Old 09-29-2003, 11:04 AM
Charlie Mitchel
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Vacume:

By the reading you gave from the pump "you have good vacume." I suspect as you, the damage was done before motor swap out.
I would not try and do a soap rinse. I would replace all rubber lines and connectors. Problem with the soap or brake cleaner, great for cleaning line but when it get's into componets it may screw them up.
If it was me I would start under the hood and replace rubber line's. The plastic lines use the brake cleaner but make sure it is dry before blowing into system.
There is a plastic fuel filter attached that does into the car and is connected to nothing. This is a vent.
You will also see some little blue and black or yellow and black plastic connectors. These are "one way valves." Make sure they work and are in the correct direction.
If you have a digital camera shoot picture other wise make a "good" diagram of all lines before.
There is a ton off vacume on these cars.
Charlie
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  #12  
Old 09-29-2003, 02:34 PM
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well i already started with the brake cleaner on the ignition line, i hooked up a can and squirted it through the brown line and some black gooy stuf came out the other line that goes to the shut off valve and then just the brake cleaner. then i sprayed compressed air through ( since i dont have a compressor i used computer key board duster) and dried it out, hooked it back up voila! it shut right down, did it a couple times and it still works. now i just need to start on the rest.but i would like to replace All of the rubber conectors. i looked on fastlane and could not find them. is ther some type of kit i can buy that will have all the parts neccesarry?
thanks
william
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  #13  
Old 09-29-2003, 04:03 PM
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All the lines and fittings are available through the dealer. Although its a challange to find them all a good parts person can do this if motivated.

I replaced every hard line/soft fitting on my 300SD last year. Along with this process I placed two fuel filters into the system. One goes in-line with the vacuum shutoff at the IP and the other goes in-line with the vacuum takeoff on the brake booster hose. The see-through filters let you visually inspect for oil crawling around the vacuum system. Anyway those hard lines get brittle with age and soft fittings crack. It's not to expensive to replace them as a PM activity.

art

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