2007 DF140 Corrosion...What next?

[Loosewire]

I've been reading this site all week after finding water in my DF140 engine oil when I went to change it last week. I confirmed my oil cooler needed to be changed as it is completely blocked, so I don't see how water could get from it into the oil. I also had corrosion around the steel exhaust plug which ended up being the reason for the tear-down.

My question is this...when we were removing the long bolts from the engine holder to the block, one broke off flush with the block. All the other bolts came out with no issues. Due to the corrosion around this bolt, I'm unsure if there is a fix for this. Based on the picture, does it look like this block is worth repairing? If so, what can be done to fix it?

What about the surface between the exhaust and the oil? It is very rough...possibly a couple thousands of an inch in corrosion pitting.

Is it possible this is where water was entering my crankcase? Or possibly a head gasket, or worse...corrosion farther up in the block?

The engine is a 2007 with 350 hours used only in Salt and Brackish water, flushed after every trip and stored in a garage. Compression test yielded 180-185 across all four cylinders last week, which seems low to me based on what others have reported.

I hate to sink a couple grand into this engine in parts, gaskets and machine shop fees when I'd really like a new DF150 for this boat IF I'm chasing a ghost here.

[jHydroman]

The broken bolt shouldn't be a game breaker. There a couple options to remove the broken bolt.

1. Soak broken bolt with Kroil (penetrating oil) and apply heat to area around several times (allow to cool after each application) Use quality left hand drill ( starting with smallest size available) progress to larger diameter drill bits. Hopefully at some point one of the drill bits will grab the broken bolt. If this doesn't work, enlarge hole and install Heli Coil.

2, Center washer over broken bolt and weld to broken bolt. Then weld nut to washer, you then be able the remove the broken bolt. make sure you apply penetrating oil after attaching nut.

Depending on degree of corrosion on mating surfaces, if it is not too deep you could have the surface machines is it is only a few thousands.

Jim

[artdf175]

agree the bolt should not be a big problem
the heat and penatraing oil works and there are cheap extraction bits you can get at anyplace that sells drill bits
they have a left handed bit on one end and a tapered extractor on the other
if the gasket was not sealing well and allowed corrosion to form I would think that could be an obvious source of where water was getting in and head gaskets are the other
your compression readings look to me to be in the normal range
Your service manual will tell you what the range is for you model
seems you have already done all the hard work getting to this point
Art

[jHydroman]

When it comes to tapered extractors, I have has better luck with the ones with straight tapered flutes vs spiral flutes.

You can drive the strait ones in and they seem to bite and don't expand the broken bolt as much preventing the additional fiction between the internal and external threads.

I have found welding the washer/nut works the best if you have the skills and proper access.

Jim

[Loosewire]

OK, thanks for the feedback. I will get some of the extractors and work on getting this bolt out. I'm assuming as for machining the surface, I would have to remove all the gears, oil pump and timing chain. That sounds like the worst part of this....timing issues and all.

[Ole Joe]

I have a pair of 2003 DF140s over 2,000 hours on them, one of which was getting water in the crankcase oil. It was not a lot, but it was apparent after about 100 hrs. I was pretty sure that salt water corrosion had gone through the block or head because of age. I learned that others had found the source of the leak to be the oil cooler. I had planned to replace the cooler, but before I did I wanted to make sure that it was the problem, not the block or head.

I pulled the cooler and found that portions of the internal o-ring surfaces were corroded. After rebuilding the surfaces with "Metalset" and installing new oil rings, the problem was cured. I ran the engines all of last season without a trace of water in the oil. New coolers are now ordered for both engines.

[jHydroman]

I would clean the block surface to determine actual condition, I have had success with Devcon and Belzona products on gasket surfaces on large machinery, Also use a quality gasket sealer during reassembly on both sides of the gasket.

Machining the surface without removing the components that you mention could probably be performed with a CNC machine with a end cutter. You want to make sure you don't contaminate the parts with metal chips when machining. Also must make sure that you don't machine to much that causes contact with gears and chains.

Jim

[catacom225]

I Just disconnected the water hoses and joined them together , I would bet more than half of those oil cooler are blocked, once you see how small the inlet and outlets are you will agree, a few grains of sand or salt is all that is needed to stop the flow

[Loosewire]

I Just disconnected the water hoses and joined them together , I would bet more than half of those oil cooler are blocked, once you see how small the inlet and outlets are you will agree, a few grains of sand or salt is all that is needed to stop the flow

I’m not sure why they even put them on there. I doubt they make much difference anyway.

Good news is I got the engine holder welded this week and a buddy is going to try to get the broken bolt out today. New oil cooler, bolt, o-rings and gaskets should be here Friday.