Diesel Fuel in the Oil

[JimHamlin]

Hey there, here's a puzzle I don't see mentioned on any of the TOW VEHICLES posts. My ford F350 is currently in the repair shop, having the sensor on the Horizontal Fuel Conditioner module replaced. Seems that previous owners didn't bother to replace the fuel filter on that unit, and over the years alot of crud built up inside the module itself. Here's the problem: the mechanic also stated that the oil level in the crankcase was at least 3 quarts HIGH. I had him drain & replace with new oil and he stated the old oil smelled like diesel fuel and was much too thin! A leak test on the injectors showed all in good shape. So the question is, what could be the other possible ways that fuel could find it's way into the crankcase? I understand that if you shut down the engine in the middle of a regen, this might cause excess fuel to "dump" where it shouldn't. Thanx in advance for any feedback from any of you experienced mechanics or engineers.

Jim

 

[JohnDar]

Piston rings

 

[Hastey]

Piston rings

Times two

 

[porthole]

3 quarts is a lot of fuel and sounds like an injector/s issue as well.

 

[RoadJunkie]

Do you spend a lot of time idleing? Diesels dont like to idle, it causes blowby, past the rings and into the crankcase. Google something like F350 making oil, there is a lot of discussion on forums on this topic. I added the fast idle to one of the upfitter switches to prevent low speed, extensive, idleing. May not be your problem, but worth the google.

 

[scottyb]

3 quarts is a lot of fuel and sounds like an injector/s issue as well.

That's usually the culprit on heavy equipment but he said they tested the injectors.

 

[JimHamlin]

That's usually the culprit on heavy equipment but he said they tested the injectors.

Thanx for all your comments so far. We now are scheduled to take her in to a Ford garage next week, since the place we were at serviced all makes/models and they confessed they were puzzled and couldn't figure out the water-in-fuel issue either - after cleaning out the fuel conditioner module, changing water filter (on the engine itself as well) & installing a new water sensor. I checked the oil level and it's right where it should be. Not an engineer, but I don't think it has to do with compression or rings, since I've never seen blue smoke out the exhaust. I'll update this thread as soon as the next shoe drops . . .

Jim

 

[JohnDar]

I would think you'd only see blue smoke if excessive oil was getting into the combustion mix at the top of the piston. Fuel dilution in the oil has only one way to get there and that's by going past the piston rings. Rare, but what may happen is the splits in the rings get aligned and you have a path for fuel to get blown past the piston into the crankcase. Or the rings/piston cylinder wall are worn.

Water/coolant in the oil is another matter and a different route of entry. Spent a lot of time analyzing engine oil samples back in the '80's for a new engine design that went south when it left development and into production.

 

[TXTiger]

What year is your F-350? Is it a 6.0, 6.4 or 6.7. I understand that the 6.0 and 6.4 models had injector problems.

 

[MCTalley]

If it's a 7.3, probably injector o-rings. However, by your earlier comments, it sounds like you have a 6.0 or newer.

 

[JanAndBill]

The likelihood of excessive unburned fuel getting past the piston rings is pretty slim. It would require excessive piston ring wear and an injector failure, both of which would show up in the exhaust or performance. As Malcom pointed out injector top O-ring failure could be a problem, as could some other things. You don't mention which engine you have and unfortunately each have some unique problems. The latest I've read about is excessive regen.

 

[JimHamlin]

What year is your F-350? Is it a 6.0, 6.4 or 6.7. I understand that the 6.0 and 6.4 models had injector problems.

Sorry to leave this out . . it's a 2008 6.4 diesel dually. Checked the oil again today after running around in town yesterday, and it's right where it should be. I even "short sticked" it to be sure. If this happened once, I'm sure it'll happen again, but intermittent problems like this are the hardest to find. On the "water in separator" issue, I'm inclined to think that I've either got an electrical ground problem with the fuel conditioner module itself - causing an invalid code, or possibly the lift-pump in the fuel tank not delivering fuel under the correct pressure. Have high hopes the Ford techs can sort it all out. I have over $4 grand into repairs since purchasing this mule in January. I'm gonna look to see if anyone offers a bumper-to-bumper warrantee on it, after it's squared away. Simply cannot afford continued and unexpected problems like this, since we're full-timers. If that doesn't pan out, we'll be doing a trade for sure!

 

[BHEWITTJR]

I am a mechanic for a school bus company that services around 350 busses, and roughly 90 of them have that motor in them. They were all new in 2009, since we put them in service they all have the same problem with fuel in the oil. going back and forth with International they have tried a variety of fixes and none of them seem to have worked. Yes we have wasted a couple of motors from it and IHC warranted them with remanufactured engines and they still do it, so their latest stab at it was just keep changing oil at specified intervals. This engine is the one that broke the relationship between Ford and International. Good luck with Ford and keep checking your oil.

 

[scottyb]

This engine is the one that broke the relationship between Ford and International.

Yes the 6.4L was the last engine Ford acquired from IH, but it was not the engine that was responsible for the lawsuit that was filed in 2007. The lawsuit was based on warranty claims for the 6.0L.

 

[JimHamlin]

Well we finally got the water/separator problem resolved by replacing the old fuel-conditioner unit with a new one. Seems that even 'tho two attempts were made to clean the old one out, there was too much crud that wouldn't let go of the inside of the casting. Still no explanation for possible fuel mixed with crankcase oil a couple of weeks ago, so I'll just have to keep an eye on the oil level. As someone mentioned earlier, the only way this could happen is via the injectors - since there's good compression on all cylinders - but no corresponding codes have been thrown to-date. Many thanx again for all of you who took the time to respond . . nice to know you're not totally alone when something like this goes afoul!

Jim

 

[Jim.Allison]

They know how the diesel get into the crankcase. Amsoil postponed the introduction of synthetic oil in the ford diesel because of this. During the regen process the ford inject diesel in the number 7 and 8 cylinders. It is supposed to burn the soot out of the exhaust filter but in some cases it finds its way to the crankcase. Anyone that tells you that they don't know why this happened is FOS because we have been making diesels for about 100 years now. And in mass production for the last 50 years. They know!!!! You are not the only one........