massive fuel leak '86 300SDL
 

See attached picture, suddenly from the top of the fuel distributor, I'm losing at least a tablespoon a minute? Any ideas? Everything seems tight?












'86 300SDL 202,000
'91 560SEL 88,000
'94 SL500 22,800

I'd have to see more than that. The pic is actually the top of the fuel injection pump. I would be surprised if it "suddenly" started coming from the tubing fittings that are shown. You need to look deeper in there and try to ascertain exactly where it is coming from.

How does it run...rough, normal or what? Are the fuel return lines (between the injectors) in good shape? Is there any fuel leakage evident near the injectors themselves? Need more info to help ya.

Spray some brake cleaner or something alike, to clean that pump up. Then start the engine and see where exactly it is leaking from. Diesel is really a thin oil, and like oil, spreads. So you could have small leak that spread.

There was some minor leakage from the fuel return lines, so I replaced all of them. The wet areas surrounding the fuel injectors are now dry. Vehicle runs and operates normally. I will clean up the area tommorrow and see if I can see where the flood of fuel is coming from, it really is a huge leak, the side of the engine is saturated with fuel.

If anything, look at it as a rust preventing measure for your engine block. All kidding aside, that mess looks worse than it probably is. Here is the upshot to a diesel leak, no chance of an explosion/fire like it would be with gas.

in all probablity the injector lines have cracked at the junction. Common on the 602/603 engines which have (relative to the 617 motors) flimsy fuel lines.
This is probably a result of bad motor mounts

I cleaned the entire area, and dried it. Inspected the fuel lines they appear to be fine no leakage at all. I start the car and within a second going from left to right 1, 3 and 5, are saturated (see attached new picture), and pouring huge amounts of fuel. I checked exiting fuel lines and they are dry, just the wet areas in the photo are soaked. The only thing keeping this from being a major fire hazard is the fact that fuel delivery is on the drivers side and the exhaust is on the passenger side.

Could possibly be one or more bad delivery valve seals too.....

It doesn't matter any more what was leaking. Apparently at highway speeds the fuel leak was adequate to travel to the exhaust where it resulted in a massive fire, there's nothing left to the car, even the tires were reduced to ash in minutes. It's just a cooked piece of metal. Thanks anyway.

This is one of those posts that you read and are simply too shocked to respond.

I realize that nothing can make you feel any better about the situation but, I trust that nobody was injured, which is the most important thing.

I never would have believed that a leak that you described could be severe enough to reach the exhaust.

My heartfelt condolonces on the loss of the vehicle.

good God! I feel badly, this is cause for a wake.
I would never have guessed the words massive were indeed massive, but that must have been a realistic choice of words, in which case you should have - - - Oh forget it it a lesson for the rest of us.
:sad3: :sad3: :sad3: :sad3: :sad3: :sad3: :sad2: :sad2: :sad2:

Injector leak
 

I have replaced the o-rings (seals) on the above. Not a hard thing to do. It solved the proble. Here in CA we have a low sufler fuel and it does not work with older seals. Change them and I bet your problem is solved.
R. Ragno

But Ron, read the thread, man! His car is history!!!!!
I sure hope insurance covers it!

Man, I really feel bad. I know you don't want to ehar this but the o-rings and seals that need replaced on your acr are under $9.

David

I am sure everyone here shares your loss. Another one of these magnificient machines has gone.
I hope that no one was injured in the fire.

Would you care to share the event with us? Perhaps we may learn from your loss.

Tony

Leak
 

Can you tell us about any recent work that was done? Any symptoms or did the leak start all of a sudden?

im quite surprised to hear that the diesel ignited by contact with the hot exhaust.i wonder if the combination of diesel and brake cleaner may have been responsible for changing the ignition characteristics.if thats the case BEWARE :confused:

Possibly the brake cleaner was involved, I was just thinking about my experience with a 123 that blew the plug on the last return line (#5 injector nozzle). I was driving the long boring Hwy 5 about 20 miles north of Bakersfield. I had filled up there so that's probably when it blew (I think it was one of the rubber caps they supplied for this purpose for a while, those were replaced by the metal plug that fits a short piece of return hose and is much better! Hint - anyone having those little rubber caps? Throw them OUT! :eek:
I was smelling diesel and stopped to see what it might be, only to discover diesel fuel running down the firewall and all over the rear drivers side of the engine. It was spurting from the open end of the last injector. I scrounged up a small screw, cut off a section of hose that could be srpared (luckily the long run between filter cannister and first injector was longer then it needed to be) and stuck a screw into one end then put it on the open nozzle and took off down the highway at 70+ MPH. After a while I noticed a car following me pretty closely then he turned on his w/s wipers and backed waaaaay off. It was a clear day, so I figured I was trailing diesel because I still smelled it a lot! I pulled over to see and sure nuff, the screw was gone, I guess it was too small. I said the heck with it and got back on the road. I must have left a trail of fuel all the way to San Francisco, approx 250 miles. I stopped at a DIY carwash as I got close to "humanity" and used the pressure spray to remove as much fuel as I could. I looked under the car and saw it had coated everything back to the center muffler (the exhaust line crosses over to the drivers side) and I thought I was lucky it didn't catch fire. In restrospect I was pretty stupid, but I really enjoyed seeing that tailgater back off. A diesel coated windshield is probably becomes a streaky mess when one hits the w/s wiper button!

O-rings, leaking fuel
 

Oops, did not read the whole list. I will do better the next time.
Thanks,
Ron

OK no problem, Ron I too sometimes jum in before getting "calibrated" on a subject.
BTW I wonder if the 126 undercover might have factored in somehow, accumulating the fluids?
The 123 is wide open so fuel will drip to the ground, except at high speeds it gets blown back against the firewall as I have seen firsthand

Still, I hope insurance covered the loss. We may never hear from jcciem on this thread anymore, I see he owns two Benz gassers though.

Fuel leak
 

The engine noise shield could have contributed to it. I wonder if he ever looked under the hood before? I, think he would have noticed the smell long before the fire. Shows, no substitute for good PM.
Ron

Major bummer.........Luckily that has never happened to me..........as close as I got was a Fiat 500 I sold to a guy I worked with went up in flames 2 weeks after I sold it.

Typical Italian engineering Carborettor being directly above an ignition sourse. The distributer.........Warned the guy to keep an eye on it...one day I saw it along the road roasted to a crisp........He felt it run rough looked back and saw smoke and flames out the back window. Lucky nobody was hurt.

Cars can be replaced....not true with people.

Very sorry to hear about your misfortune. I must say too, that this is the first time I have ever heard of a fire igniting from diesel fuel, but I do not think any car should be driven with a fuel leak, or any leak for that matter.

How soon did you start driving the car after you cleaned the engine? Did you clean the entire engine compartment? Perhaps something got wet that should not have and caused and electrical fire? Did the car stop running before you knew it was on fire?

That is another reason why it is very important to carry a fire extinguisher in all cars, at all times. Never know when you, or someone else may need it. It may have made a difference if the blaze was detected early.

Good luck to you.....