leaking injectors. 1984 300CD
 

I recently degreased my engine compartment with gunk degreaser and a power washer prior to valve adjustment. I now have 4 of 5 injectors leaking at the base of each, return lines are all dry. Could something in the Gunk have dissolved a seal or o-ring??


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No. It is all metal-metal seals, no rubber anywhere. Does the "base" mean at the joint between the upper and lower halves? If "bubbling up" there, you would have to remove them to clean the interface. However, they would have been leaking for a long time. Blow out the liquid with air, or w/ paper towels, so it is perfectly dry. It could just be the Gunk is sitting in the crack and not a diesel leak at all. If it is a leak, more likely it is where the tube attaches at the top and is dribbling down the side and collecting in the groove. The tubes often get a crack on the ferrule, from vibration.

leaking injectors
 

Bill:
I cleaned the area around the injector base with detergent and blew everything off with compressed air until dry. Started her up and watched the diesel bubble out at base/ threads.

What is the condition of the return hoses (aka leak oil hose)? If they are weakened, then fuel can dribble down from the leaky hose and look like it is weeping out of the injector itself.

Weed wacker fuel hose will work in a pinch but it will only last about a year. The proper return hose is available from the dealer or the buy parts link at the top.

If that's the case then you have a compression leak around the injector..Either someone reused the heat shields,forgot to put them in,put them in upside down or didn't torque the injector to spec when installing them....

If you are speaking of where the Injector screws into the Cylinder Head (actually into the Prechamber ring) there is some space between the Injector and the the Prechamber Ring that can fill with Oil or other Fluids.

When that happens those bubbles appear. I believe the bubbles due to the shock of the Fuel Injection and maybe even combustion.

Spray Brake Cleaner around that area and the idea is to mix what is in that cavity with the Brake Claner and have it float to the top where you can soak it up with some Rags.
Eventually you sould get enough of the Oil out that there is no bubbles and the Brake Cleaner will evaporate.

The pale orange area in the pic is were fluid can pool.

definitely not saying it cant happen to be a leak from the injector, but you'll swear up and down its not the hose leaking but it really will be. if the injector return nipples are nicked or chipped it will exacerbate the problem. the cloth braided hoses will look totally fine but if you go to pull them off they'll just disintegrate.

Hmm
 

Even in 70° F or warmer weather, it takes many hours of driving to boil off water / fluids trapped under the pre-chamber torque ring.

IMO it is risky using a power washer near the cotton braided looped fuel return hoses, under normal operation they become seriously delicate = don't like bending near the injector barb, and fail prematurely.

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^ Agreed.

Inspect the fuel jumper lines.

Leaking injectors
 

I'm ordering some fuel return line and will try that first. If that doesn't work is the next step to remove injectors and re-seat?

Until your proper return line arrives, you can go to the Home Big Box and get some weed wacker fuel line as a temporary replacement.

If you pull the injectors, you will need to replace the heat shields beneath the injector. They are one use items.

I used some degreaser on the motor and my injectors look the same, wet around where the injector screws into the prechamber, all fuel return lines are new, everything from the top down on the injectors are dry.

what ever became of this? was it just water that finely evaporated?

^ Did you have the injectors out?

Didi it leak before?

There was a lot of fuel and oil around them before I cleaned the motor. Only one looks like it is wet now.