Volvo MD22L-B fuel dripping from air intake
- Thread starter Rich Stidger
- Start date
Getting there. In this life I only have problems with things that have keyboards, engines, and long hair......
I think those bolts attach the exhaust manifold/HX to the block.
And while you are looking at this great picture of the engine, puzzle me this- How can fuel get to the bottom of the bell housing from the engine block and oil pan? All of the fuel lines and connections are forward of the bell housing on the other side of the engine. So leaking fuel would have to travel along the block to the bell housing and then down the front edge and gather at the bottom. But I have searched extensively and cannot find a leak, never-mind a wet path to the bell housing. See your picture of the other side of the engine in post #13. The starter is completely dry as well as the secondary filter above it.
The wettest part of the engine is the bell housing bottom edge. From there the fuel could easily run fore and aft to form pools. So if the bell housing is the drip-off point, how does fuel arrive there?
Well the injector pump connections you show are dry, and the drip point you show is the crankcase not the bell housing.
Possible pinhole leak on the fuel filter shown in the picture above?. Or one of the washers on the banjo fitting?
Well I wrapped the entire filter in a paper towel. After a couple days there was no trace of a leak. So it doesn't seem to be the filter or its connections.
The fuel tank is 6 feet away with no path to the sump under the engine. The supply and return hoses are completely dry, so fuel can't be running along them.
Ok that means the fuel lines are still under pressure.
Then a line slowly drips for a few days.
This Line would be suspect at the fittings. aka Aft cylinder fuel
Jim...
That is the hardest injector to reach. I will see if I can wrap that area with tissue to detect a leak there.
No I haven't. The leak seems to have either stopped or slowed. I have purposely left the drippings in the engine compartment pan for the last couple of weeks because it seemed pointless to keep cleaning it only to have more drips the next day without finding any source. So I have just returned from our Maine cruise and have topped off my fuel tank. I will clean everything up at this point and start anew.
The only spots where I can feel fuel dampness is on the injector fuel return connections. But there are no drips, just wetness if I rub my finger across the bolt. That doesn't seem like a source that would put a small pool of fuel in the compartment pan. And if they are the source, I can't find a drip trail down the side of the engine. The under edge of the bell housing is also damp, but just enough to wet my fingers, and I can't find a path from the return lines to the edge of the bell housing.
I am planning on ordering a set of copper sealing washers for the fuel return lines. But I am hesitant to actually replace them if I can't be sure that they are leaking and leaking enough to qualify as my leak. I am always hesitant to take stuff apart if I am not certain that I will make it better. Too many times I have disassembled something and either not fixed the problem or created a new problem.
UPDATE:
Finally! I believe that I have found the source of the leak. After leaving the boat with a full tank of fuel for 25 days, I returned to find 21 ounces of diesel in the pan below the engine. The pan has valleys and peaks in the surface, so the fuel can drip in one spot and easily run to the other end of the engine. This doesn't help when you are trying to locate the source.
The only spot that I could find that was wet with fuel was at a TEE that connects the fuel return lines from cyl 1&3 and 2&4 and then connects to the injection pump and then from the pump there is a rubber hose to the tank. Wrapping a paper towel under that TEE showed that it became soaked with fuel after just an hour.
From this leak the fuel dripped onto a black vinyl tube that contained wiring and then followed the tube to the transmission end of the engine. This was key, because I could not figure out how the bell housing was wet with fuel when there was no fuel connections in that area. The pictures below show the vinyl wiring tube under the leaking TEE and then the path of the fuel to the starter pinion gear bump and the bell housing.
But finding the leak is just the first step in the fix. The TEE uses compression fittings (ferrule and nut) to attach the return lines. My experience tells me that just tightening doesn't often work (I tried, and it didn't help) , and since the ferrule is compressed into the tubing, you can't just put on a new ferrule. There isn't enough length of the return pipe to cut off the bad part and re-make the compression fitting, so I am at a quandary to figure out a proper repair. BTW, replacement return pipes are $200 each!
As a stop-gap temporary repair, I wrapped the TEE with Rubbaweld tape. It is an amalgamating tape that when tightly wrapped will bond to itself. Intended for wrapping rigging, it can also be used for temporary repairs to stop water hose leaks. There is no claim for fuel lines, but I figured I had nothing to lose by trying.
So far after 3 days the leak has stopped.
So for those of you that have read this far, if you have any ideas on a quality repair, please share.
@smokey73 suggested cutting the return line back to a straight section and then splicing in a new line made in the shape of the part removed with new compression fittings on all ends. Other than the difficulty in cutting the return line on the engine due to poor access, that sounds like the best solution I have heard.
Are all of the hoses you mentioned here fuel return hoses ?
The reason I ask is that I just replaced all of the return fuel lines on my Yanmar 2GM20F and they are/were rubber, marine grade 1/4" fuel supply hoses with barbed fittings. I am wondering why yours are pressure rated steel.
The reason I ask is that I just replaced all of the return fuel lines on my Yanmar 2GM20F and they are/were rubber, marine grade 1/4" fuel supply hoses with barbed fittings. I am wondering why yours are pressure rated steel.
The return lines on the engine that connect to the injectors and the injection pump are all steel. At the injection pump is a barbed fitting that connects to a rubber fuel hose and then connects to the tank.
I have always heard that Volvo was REALLY proud of their parts but $200 for a small return line?!?!? WOW! Makes me glad my engine is a different color. I can get a full overhaul kit for my M25XP for $450 that includes everything from the paper gaskets to the cylinder sleeves.
My best suggestion would be to take the tube to a hydraulic shop and see if they can fabricate a replacement. I would contact them first and show them photos of the offender from different angles to find one that would do it before removing the current one.
My best suggestion would be to take the tube to a hydraulic shop and see if they can fabricate a replacement. I would contact them first and show them photos of the offender from different angles to find one that would do it before removing the current one.