Crankcase Full Of Fuel. 1991 350SDL - Page 2 - PeachParts Mercedes-Benz Forum

DeliveryValve · #16 01-08-2015, 12:28 PM

Once you get it running, you'll need to watch for oil consumption. If it indeed hydrolocked while running, you can certainly bend a rod and an increase of oil consumption would follow after a few thousands of miles.

funola · #17 01-08-2015, 12:44 PM

I do not understand how one combustion chamber got filled with diesel purge. As you crank the engine, even if the injector was peeing, excessive diesel purge would get blown out of the exhaust valve. I don't think that a bad injector could pee while sitting and fill up a combustion chamber before you start cranking. Something else is going on.

It sounds like you did a lot of work to the fuel system over a long period of time without starting the engine. Think back if there was something you did that may have filled the combustion chamber.

Squiggle Dog · #18 01-08-2015, 02:31 PM

I put the injectors back in and cranked the engine with the hard lines disconnected to prevent hydrolocking.

I cranked and cranked and cranked the engine, but only a tiny bit of fuel was coming out of the #5 and #6 hard lines. The rest were dry. The pump was sucking fuel out of the can, but not much of anything was coming out of the hard lines.

The stop lever was down nearly in the shutoff position and didn't want to stay up. I pulled the vacuum hose off of the shutoff valve and the lever popped up. Related?

Then I noticed that fluid was overflowing out of the engine oil dipstick tube. I opened the oil filler cap on the valve cover and there was standing fuel draining down into the crankcase. The fluid on the dipstick is the same color, consistency, and smell of diesel purge, with a slight hint of biodiesel. If it were coolant, would it not be a milky color?

The previous owner had apparently bypassed the lift pump (picture below shows how he had it routed). He had an electric pump installed. I wonder if it was bad before, and was the reason it was bypassed. It may be dumping fuel into the crankcase.

I made sure that all cylinders were empty before I installed the injectors the first time. I cranked the engine over to make sure. So far the engine has consumed the biodiesel that was in the spin-on filter, and one and a half cans of diesel purge.

Squiggle Dog · #19 01-08-2015, 03:08 PM

Could this be an issue? I noticed that the bore of the banjo bolt where the pump and injector return lines connect was plugged with a piece of metal.

funola · #20 01-08-2015, 03:14 PM

Quote:

Originally Posted by Squiggle Dog

Could this be an issue? I noticed that the bore of the banjo bolt where the pump and injector return lines connect was plugged with a piece of metal.

That was done by the PO to convert it to run it on a 2 tank VO system, in order not to mix up the 2 fuels. You want to remove the plug if you want to run it on diesel only. How much diesel purge did you use? I can't imagine you used so much that it's coming out of the dipstick tube and valve cover oil filler. There must be something else getting in there. Time for the PO to chime in.

Dan Stokes · #21 01-08-2015, 05:42 PM

It just hit me that you ought to send off an oil sample for analysis. I'll wager there's engine oil, fuel, and Diesel purge - or maybe coolant. Anyhow, you need to actually KNOW what you're dealing with. Just Google for labs that do this. The last time I had a "General assay" as Ethyl labs called it, it was about $25 but that was some time ago. Mine was on a gasser and turned out to be fuel - bad engine-driven fuel pump. I thought that might have been the issue but the pump appeared to be new and I couldn't be sure.

Dan

Onetoomany · #22 01-08-2015, 08:49 PM

There are also some places in the IP that can mix diesel and oil. If you remove an injection pump, about a coffee cup of oil and a shot glass of diesel are in it at any given time. The engine feeds the IP its oil.

Going into an IP on your own is not a good idea - that's shop work. I don't know what your budget is, but I got a good used IP to my door for $250, swapped it, and my car has never run better.

Ditto on oil analysis. They can be done for $15~ online.

The fact that you are filling crankcase with diesel purge, AND you aren't getting fuel at hard lines sounds like my last IP that took a poo.

Pop the BACK plate off the IP and use a flashlight and a mirror. When they go, they go. Mine had bearing/metal/oil stew coming out the back as soon as I opened.

dude99 · #23 01-08-2015, 09:27 PM

Hopefully a rod didn't bend from hydro-locking... Good to see you back though, I've missed reading about your W116

whunter · #24 01-09-2015, 03:09 AM

Quote:

Originally Posted by Squiggle Dog

My friend was in need of a car since his was wearing out and had no air conditioning (in Phoenix, Arizona, land of 120F degree Summers). GregMN donated his 1991 350SDL to the cause.

The engine wasn't idling well and had no power for the first several seconds of acceleration. I felt a refurbishment of the fuel system was in order. I have spent almost all of my free time for the past few months replacing all the hoses, filters, and O-rings. I also removed and cleaned the intake manifold, replaced the glow plugs, straightened the hard lines and installed new clips... I've done a lot of work to it.

Today was going to be the day I would reap the fruits of my labors. I put some diesel purge in a can and cranked over the engine. It took lots and lots of cranking until finally the fuel started leaking down the tops of the injectors. I tightened up the hard lines and then cranked over the engine.

It sputtered a bit and finally started to run. Then it sputtered again and the engine locked up. It seems to be seized. The shutoff lever was pushed down nearly in the off position and required some force to push it back up, but then it would spring back down.

I saw dark fluid running out from underneath the car, but all of the hoses were dry. Odd. It appears the fluid is coming from the front crank seal, gasket on the side of the oil pan, the exhaust pipe clamps, and between where the injection pump meets the block.

Then I checked the dipstick. It was extremely overfull with a very thin liquid. It smells like diesel purge. What the heck happened?

It appears that the crankcase is extremely overfull with diesel purge, yet less than half a can actually was sucked up.

I have a feeling that the engine is done for. I am feeling really sick right now. I don't know how my friend is going to react.

YES, a bad lift pump can fill the crankcase with fuel.

Before you (panic) waste energy.

Drain the crankcase, replace the filter, and put in fresh OIL.

Then assemble everything, and try starting from your purge bottle.

A solid step by step diagnostic will save time and money.

.

Squiggle Dog · #25 01-09-2015, 07:03 AM

It seems obvious that the fluid in the crankcase is diesel purge with a little biodiesel (water would make it milky, plus the coolant level is still up where it was months ago).

I did notice before I even took the parts off, that the crankcase was a bit over the MAX mark on the dipstick and the oil seemed thin. I thought it was just from it being parked for so long and every drop of oil draining into the oil pan, plus maybe being a light weight oil since the car was used in Minnesota.

I noticed that right before it was parked, that it would barely idle, and when I would push the accelerator pedal to the floor, the throttle would not respond at all until several seconds later, then it would slowly build up speed and then take off. I thought that perhaps it was just air entering the leaking fuel hoses. The previous owner cited this problem, but only when cold. It got to the point where the symptoms stayed even when hot.

My plan for right now is to drain the crankcase into an open container for inspection. Also, to remove the lift pump to inspect and rebuild it. Then it will at least rule out this part.

I'll put in the cheapest 15W40 diesel oil I can get and will then try to run the engine again after the lift pump rebuild to see if the oil level keeps rising. If there is still fuel getting into the oil, then I'll open up the back plate on the injection pump to see if I can see fuel mixing with oil inside.

It seems like the lift pump has been slowly failing and then finally gave out completely, but hopefully I'll be able to determine this later today. Hopefully there was no damage to the engine from it hydrolocking. Or maybe it will become a rod-bender, after all.

Squiggle Dog · #26 01-09-2015, 07:09 AM

Also, I didn't know there was a back plate. I guess it's below the solenoid. I knew about the side plate.

I'm still driving my W116 but haven't done a whole lot of work on it lately. I've been working up to 70 hours a week and have been spending almost all of my spare time trying to get the 350SDL going for my friend. If I figured out how many hours I have into this car and what my time is worth, I'd probably be rich if I was charging for it.

Squiggle Dog · #27 01-09-2015, 07:18 AM

Speaking on injectors, I sent in a set of 1967 W110 200D injectors to fuelinjectioncenter.com to be rebuilt with Monark nozzles. I also sent in my pump to have the diaphragm replaced and the pump calibrated. The price was very reasonable.

Later on, I sent in the injectors from my 1980 W116 300SD to be rebuilt with Monark nozzles. When I installed them, they were leaking where the two halves of the bodies met. So then I took them SouthWest Diesel, a local Bosch shop. But, some of them still leaked. So I took the leaky ones back and one of them still leaked after that. So I took it back again and finally got them to not leak.

I plan to have the injectors and pump serviced at SouthWest Diesel if needed, but it worries me that it took 4 tries to get the injectors to not leak. I really don't want to go through that ordeal again.

funola · #28 01-09-2015, 09:54 AM

I would not go back to a shop that took 4 tries before stopping leaks in the injector halfs.

Did you get the car with the 2 tank system removed and returned to stock? If not and the purge was on, you could have pumped a lot of WVO into the diesel tank. That would not explain why you are filling up the crankcase with fuel. IMO, the most likely culprit that can put so much fuel into the crankcase is the lift pump. Can you take an IP internal fuel pressure reading? The engine will not run with zero internal IP pressure and very poorly with low pressure. Internal fuel pressure is supplied by the lift pump and regulated by the fuel pressure regulator banjo bolt on the IP. You may want to pull that banjo bolt to have a look also. For diagnostic purposes it may be useful to do the fuel pressure test before removing the lift pump for inspection/ rebuild.

But a bad lift pump still does not explain how a combustion chamber was filled with fuel to the point of hydro locking. Too many mysteries going on here.

Mxfrank · #29 01-09-2015, 10:11 AM

Quote:

Originally Posted by Squiggle Dog

Could this be an issue? I noticed that the bore of the banjo bolt where the pump and injector return lines connect was plugged with a piece of metal.

I don't understand why this was done, but I think the result would be higher pressures in the injection pump.

If this car was converted to some sort of two tank bio system, I'd rip out anything that wasn't stock.

funola · #30 01-09-2015, 10:16 AM

The stock bolt has an orifice to allow continuous bleeding of air in the secondary filter back to the tank. This orifice is plugged when converted to a 2 tank system to prevent the 2 fuels from contaminating each other.