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Old 02-13-2014, 08:52 AM
Diesel911's Avatar
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Location: Long Beach,CA
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Originally Posted by iceman104 View Post
Help. I have a 85 300sd. And when I bought it I didn't relise many oil leaks at all really. A few not a. Lot or large amounts because alot of gaske been replaced. But now the air filter breather box is leaking oil out of the bottom of it. Is this a blow by issue? Do I need new rings. Could a valve adjustment help? Its leaking a faily large amout. Thanks in advance to all who can help.

If your Air Filter Housing is similar to the 300D Air filter Housings there is a nipple on the bottom rear of the Housing that has an O-ring on it. There is a Drain Tube that goes over that nipple and that Tube passes between and below the Manifolds and behind a Bracket a Bracket that us under the Turbo and Manifolds.

The Air Filter Breather Drain ends at another Nipple with O-ring behind the Turbo Charger Drain.

What happens is there is a single Bolt or stud that holds that drain to the mentioned Bracket and that Bolt gets loose or the welded on piece of metal or Clamp on the Breather Drain Tube breaks off. Without the Tube well attached if does not say on the Nipples.

Along with the above if the Breather itself is plugged or the Breather Drain Tubing and that one way Breather Valve in the Crankcase is not opening it would fill with Oil.

Look in the DIY Repair Links there is a bunch of info on blow-by.
DIY Repair Links

A Valve Adjustment may or may not help but should be done anyway if it is overdue. Late Valve Timing due to Timing Chain Stretch does not help either and the same for late Fuel Injection Pump Timing.

But, the main 2 places Blow-by can come from is past the Piston and Cylinder walls and around the Valve Stems of the Exhaust Valves.

I don't know for sure if this is possible but I think if the Seal on the Exhaust side of the Turbo is no good it is possible for Exhaust Gasses go get past that seal.

Also in the Repair Links there is soaking the Cylinders in something like Marvel Mystery Oil to free up sticking Piston Rings or switching to Synthetic Oil and Driving a few 100 Miles; people claim that also frees up sticking Piston Rings. But, that only works if your Rungs are sticking.

84 300D, 82 Volvo 244Gl Diesel
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Old 02-13-2014, 04:42 PM
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Join Date: Dec 2009
Location: Bedfordshire UK
Posts: 534
Gummed up rings from WVO causing blowby , below is a cure
Wall paper stripper steam cleaning

A search on the above forum will find lots of information about steam injection cleaning gummed rings.

There is a thread titled ' water injection has cured my blowby 'but when I try to currently access it I get forum is down for maintenance.One thread (possibly the one I cannot access) mentions monitoring blowby with a pressure guage on the dipstick tube and how the pressure drops and by how much and how quick as the water injection is carried out over the course of some driving with the water being sprayed into engine (not steam this time but just a fine mist of water).

But it works and will save most engines and then after say a month or so of veg use then run it again to keep it clean.

Last edited by Murkybenz; 02-13-2014 at 05:07 PM.
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Old 02-16-2014, 06:02 PM
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Join Date: Jan 2014
Posts: 44
The oil leak seems to be worse when starting up. There is a small hole in the passenger side breather box on the bottom. It looks factory like just to drain anything that would get in it. Its dripping oil strait down. The only way I know it could get in there is from the blow by tube from top of engine to breather box. Is this normal. Anything I can do to fix or slow it down ?
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Old 02-19-2014, 02:06 AM
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Join Date: Jan 2014
Posts: 44
Diesel911 thanks for your help. But idk where to find this drain tube. Where does it lead to the oil pan? And what is a good way to clean it?

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