Well I think its time to replace my fuel lines. The car smells of diesel all the time so I looked under the hood and the return lines appear to be spilling diesel on the engine and on top of the primary fuel filter.

I am looking to get the lines fixed asap and I was wondering if Autozone Diesel fuel hose would work until I bought the OEM stuff from the dealer later this week, also is there anything else I should check while doing this.

One last thing is it normal for the fuel to smoke a little when spilled on a hot engine, I noticed this when the car was running with the hood up. It was a very small amount of smoke.

Thanks for all the advice in advance,

-Dan

You are describing two different hoses, I think. The ones leaking on the engine are jumper lines between the injectors and from the secondary pump, get OEM stuff, no clamps, it's sold by the meter. I've heard some folks use weed eater fuel line in a pinch.
The line to the primary, the inline clear, fuel filter can use 5/16 inch stuff, use a clamp.
And, it wouldn't surprise me for the fuel to smoke, we're referring to fuel oil, which has a high ignition temperature, so you won't get a flash flame as you will with gasoline.

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83 SD

84 CD

Thanks for the reply, I just wanted some reassurance. Also I think I failed to describe one of the leaks properly. I think the leak is coming from a braided line that leads to the top of the spin on fuel filter, just a small amount puddles on top of the filter and the braided hose feels damp, I intend to replace this with the OEM fuel lines once I get them.

Please let me know if you think another line may be causing the issue.

-Dan

I use poly fuel line from a ATV/Motorcycle shop for my return (braided) lines. Pretty sure it is 3/16". They work fine.

The leak you describe could be either caused by the hose itself or the banjo bolt/washer on top of the filter being loose. Check the tightness of the bolt first.

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2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

the banjo bolt also generally has an o-ring which may need to be replaced, 85' models have two o-rings on the banjo bolt.

sounds like a leaky mess, guess fuel prices have not had you down until now.

Okay, that's the same hose as the jumper lines. The stuff gets old and fails, a routine replacement item.
That is the secondary filter.
My CD does not have a washer on the secondary filter banjo bolt, but the SD does, I use a composite washer from the hardware store, a #30 cap thread gasket.

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83 SD

84 CD

Well I did a diesel purge and everything was great until a few days later when my car always smelled like Diesel. Not a hit with the ladies. Then I noticed all of the fuel smoldering under the hood. So I am sure the new hose and o-rings will fix my problem.

Thanks guys,

-Dan

Release the pressure first by taking off the fuel cap, or you'll have fuel shooting out everywhere.

^ Only if you have a clogged vent line, but a simple precaution.
The purge may have hurried the failure of the lines, replace those and try without the 'o' rings, that is not causing the leak, maybe a crush washer, but new lines first for sure.

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83 SD

84 CD

For those who might not have a Mercedes Dealership near buy; NAPA (National Auto Parts) and the VW Dealer (for the old Diesel VW Rabbits) also sells the Fuel Return/Jumper lines.

Things I have tried:
3/16 Vacuum Hose- it lasted about 1 week and started leaking. The Diesel Fuel ate through it. However, it could get you buy until you get the real thing.

3/16 Silicone Hose- Worked great and never leaked. Except that 1 and 1/2 years later when I wanted to remove it I found it was rock hard and ounce pulled off could not be used again.

Since the price of Fuel has gone up I keep some Fuel Return Line/Hose in my trunk. No point in leaking away my money.

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84 300D, 82 Volvo 244Gl Diesel

Well I called the dealer today and asked for a quote before I swung by and picked it up. The parts guy said it was out of stock and that it would cost $57 a meter!!!! How absurd. I went on e-bay and found a kit of pre cut OEM hose for my engine for $21 shipped. I sure do hope that tech guy was confused because if MB sells stuff like this for prices like that then I have lost a little respect for them as a company.

-Dan

I would go with a viton hose to resist bio diesel and not use the oem original.

Did you buy it from ebay?
How did that work out?
Who was the seller?

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83 300TD (need rear wiper assembly dead or alive)
84 300SD Daily driver
85 300TD almost 400k miles and driven daily.
98 E300D *sold
86 300SDL *sold and made flawless 10 hour journey to new home.

I'm in the process of repairing weeps (not actual leaks). LOL.. The line going to the Primary filter (small clear plastic one) is weeping (moist). Picked up 5/16 Fuel injector line with the appropriate clamps.
Then I'll tackle the IP (injector pump). Top of that is wet. Ordered the special spline socket. That should take care of the diesel smell somewhat.

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92 300D 2.5L OM602 OBK #59

Really good fuel line that is compatible with WVO, Biodiesel, and Diesel is
SAE30R9 and can be had at most good parts supply houses. I got Viton return from the injectors line from a company I do not want to promote.

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Gary
OBK #37

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=190342654876&viewitem=&sspagename=ADME%3AB%3AEOIBSA%3AUS%3A1123

Theres link to where I bought it on E-Bay, ill let you know how it works out when I get it.


-Dan