On a w123 of the 3 metal lines going to tank which one is the supply and which one is return?

seems to me the supply comes out lower on the tank, but if you climb under it you can figure it out.

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1984 300TD "MAX" 303K+ still going...
fast '70 Chevelle 200k+
home built Shovelhead chopper

The fuel line the clear plastic primer filter connects to is the supply.

The line the Fat Black "Cigar" hose connects to, is the return line.

Charlie

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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

Why would the return line need that cigar hose ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

the official answer is the cigar hose flexes and quiets the return pulses from the Injectors...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Are those return pulses under pressure ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Yes. Without it there will be a thumping noise in the cabin. Like water hammer.

It works like an absorption muffler, letting the pressure waves expand, slow and dissipate energy.

I understand and agree with that...
but what ' obstruction' puts that fuel at that point under pressure ?

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Some where in the FSM is the answer.

The Cigar hose is still the return.

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 same it does with water hammer, inertia of the fluid and pressure waves.

On the sedan tank - the only one I know - you'll find a single line on the right hand side of the car that is separate from the other two lines. (Right hand side is taken as though you are sitting in the car looking out the front)

This one has the course mesh fuel filter (in the tank) and it is the supply line that goes to the small clear (or should be clear) filter next to the injector pump - just as Charlie says.

The other two lines are more on the left hand side of the car and they are the return line and the vent. You can easily trace the vent back from a little rubber mouth piece that is situated just in front of the subframe on the left hand side.

The return line with the nice bit of flexible rubber - that reduces vibration due to the pressure pulses of the injectors - come off of the larger assembly with the spin on / off fuel filter.

Disclaimer:- this is correct for a 123.130 chassis!

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!