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Old 03-16-2001, 09:55 AM
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Join Date: Dec 2000
Location: Boston area
Posts: 31
Are the '85's different??

I've got an '85 wagon that has the same issue as above, a little oil in the bottom of the airfilter. The only connection to the airfilter housing is a single vent from the valve cover housing. I am the original ownwer and have religiously had it on a 5k mile oil change and valves adjusted every 15k. I have never had to add oil between changes and it is never down half a quart at change time. I do use redline from November until April and have no starting problems. I'd use it year round but it's hard to find in the northeast and fastlane never seems to have any.

Although everything runs good, I only get 13" of vacuum and know that this is on the low side. what could I expect from a vacuum pump rebuild in terms of added performance?


PS: My breather hose is a one piece slightly flat (not round) hose directly from the valve cover to the aircleaner housing. Anyone know the correct part # for this and are the '85's different from other years. (part # 617 010 03 70
is the round hose)
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Old 03-16-2001, 11:53 AM
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Join Date: Feb 2001
Location: Midwest, USA
Posts: 171
81-85 300TDT

Here is what I found out about the 617.95 breather system in the 81-85 300TDT:

The engine blow-by gases and cylinder crankcase vapors are routed to the air cleaner through that hose, but they end up in the air cleaner at the cyclonic oil separator which is inside the air cleaner. From the oil separator the oily gases/fumes/vapors are routed through the large intake line in front of compression and together with the intake air into the combustion chambers.

The oil separated in the cyclonic oil separator flows through a return line and check valve installed in the upper half of oil pan. The check valve prevents that the vacuum in intake system will draw oil vapors out of the oil pan.

So, you can see that the air filter is supposed to have oil in it. It should drain back down to the oil pan. You will see two tubes below the air cleaner and turbo which carry oil back to the pan. This is how you know if you have a cyclonic oil separator in the air cleaner. The other tube is the oil return line for the turbo cooling.

Both of these lines are prone to oil leaks, and I would suggest checking that check valve so you don't have oily gases being drawn into the air cleaner or turbo.

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Old 03-17-2001, 12:01 AM
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Join Date: Jan 2001
Location: Tucson, Arizona
Posts: 758
Wrong Hose Guys

Greetings Fellow Oil Burners,

The line I was referring to that goes to the air filter housing comes directly off of the vacuum pump to the top of the filter lid. The valve cover oil vapor hose comes off the top of the valve cover on mine, to the intake manifold. I think '81 and newer used the oil seperator especially after they added the turbo to the engine. Mine just sucks normal air, not compressed from a turbo.

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Old 03-17-2001, 08:22 PM
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Join Date: Jan 2001
Location: Tucson, Arizona
Posts: 758
It's fixed

Greetings All,

I appreciate all the input that was provided as well as additional conversations. I got the baby fixed today, vacuum pump repair kit that is. Mine was a single diaphragm that is part number 586 41 43 from Parts Shop, and I must admit they got it to me quick and the part was accurate, Thanks Guys. If your vacuum pump has two lines coming off of it, one black going to the brake booster, and one clear going to the air filter lid, then this repair kit is what you need to get things back into order, vacuum wise. What happens when you get a small tear in your diaphragm is that it will start sucking oil from the engine mounting seal and with a vacuum applied to it, it's pretty easy to do. You may or may not see the oil travel through the clear tube to the filter housing, but if you remove it from the lid, it will surely puff oily fumes and start dripping oil after it's warmed up. The volume of air is actually more if it's leaking because it's not appling the proper vacuum to the system as it should. You also need not remove the entire pump for this repair, if you have agile or smaller hands that is. You can remove the outer bell where the diaphragm is located and replace it from there. An offset screwdriver is almost a must though if you choose this route. I'm pleased with how it all came off and went back together without any hitches. Don't forget to pull the old spacer washers off the old diaphragm and put on the new. They may be hard to get off but they aren't threaded, so just pull on them to release them from the old diaphragm rubber. Entire job can be done in less than an hour. The poppet valves that hold the vacuum as well as act as check vales can be cleaned an reused, they're made out of teflon or plastic, so wear isn't a real big factor.

Thanks Guys,


Good weather permitting, the valve seals get replaced tommorrow.

[Edited by can-do on 03-17-2001 at 08:31 PM]
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Old 03-18-2001, 10:27 AM
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Join Date: Feb 2001
Location: Midwest, USA
Posts: 171
Great Job Charles!!!

Your old pal, Patsy
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