Probably behind the wall between the sink and the clean out port. You should be able run a snake in thru the trap and then see it at the clean out port if they are on the same line and they probably are.

__________________
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

Visit your local tool rental store and see if they have what is called a Kinetic Water Ram. It is an air cylinder that can be pumped up or charged from an air compressor that then administers a charge of air to the drain, which should be full of water. It creates a movement of the water column which is analagous to hitting the obstruction with a hammer. Only 10% of the force is exerted on the wall of the pipes. Be sure to follow all the instructions!

Air or water pressure on the blockage will only work if the blockage is upstream of the vent. If it is downstream of the vent, all the pressure will go up the vent and not against the clog.

__________________
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

Underground.
If you have a crawl space, you can see where things, all drains, come together. The clean out port is quite a handy opening to clean out the sewer to your house. I lived in a house where you had to dig down to the connection to run an auger.
This is between the house and street.
The kitchen drain and all the other drains connect to a single sewer drain and must be lower in elevation. All drains have a vent too. Newer homes have a single vent through the roof, they connect in the attic. Older homes have one at every drain, kitchen, bath, washer.
MTI, I've already had one!

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83 SD

84 CD

I trick or treated the neighbors for an auger and they all said to use the device toomany MBZ suggested.

I'm trying to estimate the backflow from such a device so I can be ready for it. What used to be a backyard is now a covered patio The cleanout branch is a simple tee into the drain pipe. It's not angled to facilitate pressure cleaning. What's to keep the pressure from blowing out the kitchen drain which tees in above the cleanout port (thanks, Kerry) and up the vent?

There's no basement or crawl space. The house sits on a slab.

Sixto
87 300D

Home Depot sells a Zep product that is a mixture of lye (sodium hydroxide) and bleach (sodium hypochlorite). It's worked on my wife's bathroom sink many times. I usually try chemicals before mechanical stuff...

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

On slab, after potato peelings run through the garbage disposal clogged my drain, downline of the cleanout access - I took the drain apart under the kitchen sink and proceeded to stick my high water pressure gardeen hose in a foot or so, then sealed around it best I could. I turned it on full blast, and after 30 seconds water was shooting out of the gas vent on the roof! What a sight! I called in the professional at that point, and haven't tried running potato peeling down the disposal - ever again. Shrimp shells can stop up your pipes too, btw.

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'06 E320 CDI
'17 Corvette Stingray Vert

I've heard of people forcing compressed air through the vent pipe; just be sure to cover the sink drains with a rag or else a mess will very likely blow out of the drain...
Also take care not to use mechanical methods with any amount of drain cleaners stuck in the drain...

__________________
Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

I sent 25 feet of 1/4" auger down the cleanout port. There were some sticky spots but nothing a little back and forth didn't push through. The d@mn right angle at the cleanout port prevents me from fitting a pressure bladder. I guess I'll call a plumber in the morning

Sixto
87 300D

Is there water from the sink running by the clean out port? Sometimes the plug is just accumulated sludgy goo that is not felt as a 'plug' by the snake. But the snake loosens the goo and the hot water drives it downstream to a larger pipe.

__________________
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

I can see what drains from the kitchen sink flow down the cleanout port. I'm convinced the line is clear from the sink to that point.

The last thing to go down the kitchen sink before the clog was two oranges worth of peels through the garbage disposer.

Sixto
87 300D

I wonder if a plunger would help...

__________________
Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic

Is the water backing up to the cleanout port? How close is the sink to a large main line? Sometimes kitchen sinks can be a ways away from a larger pipe. If you can see where the sink drain empties into a larger main line or make an educated guess and measure this distance, that's the distance your snake needs to go into the pipe since it's unlikely that main line is clogged.
If your clog was the goo I mentioned and the snake has gone thru it, it is sometimes necessary to fill the sink with very hot water to get the pressure necessary to push that sludge down the sink line to the main drain.

By the way, this kind of problem is why I remove garbage disposals every chance I get. That, and the fact that it seems irrational to me to grind up food, put it in the water, only to have the wastewater plant remove it.

__________________
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

It didn't

I considered a plunger with a CO2 cartridge but I've spent enough on false hope.

Sixto
87 300D

The cleanout port is along the vent line. The kitchen sink feeds just above the cleanout port from 2-3 feet away. There's no plumbing above the kitchen.

As water runs in the kitchen sink, I see it flush down the cleanout port. Then it backs up and overflows. I didn't take a precise measurement but it recedes in the inches per minute range.

I don't know the plumbing is laid out under the floor. None of the other drains in the house are backed up. Either the clog is upstream of where this line meets the city pipe or there are multiple routes to the city line.

With the advances in nanobot technology, you'd think drain clearing millibots would be available at Harbor Freight.

Sixto
87 300D