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fuel in oil on 4-53 Detroit???

Started by danbuendgen, June 05, 2016, 04:11:04 PM

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danbuendgen

Lately when checking my oil on my 1978 240 TJ with a 4-53 DD non-turbo, I know its getting fuel in the oil somehow. If I smell the dip stick, it smells like its got some fuel in it, also, I typically have to add some oil here and there, and lately I don't have too. The oil is also thin, and the oil pressure is poor. When warmed up it barely holds over 0. When wide open its just 25-35. I always run 40 wt oil and change it out at 100 hours. Its dew for a oil change now, I plan to test the oil to be sure I am not crazy.... but I know there is fuel in the oil, I just need to find out why.

The skidder starts instantly and runs good, with plenty of power. Its smokes some, but its a old DD so I dont think thats a big deal. But, there is nasty black goo in the exhaust pipe and seeping out the exhaust manifold. Is this related?

I have done some research on this, and have already checked the jumper lines to and from the injectors for cracks, I know the fuel pump can leak into the crankcase, how do I test it? Or should I just throw a new pump on it? Where is the weep hole on the pump? I would like to check it to make sure its not blocked up with skidder grime. I know the injectors can go bad, but if it starts up and runs good, I don't think this is the issue. Or could I be wrong? Can I pressurize the fuel system with my air compressor, where the fuel line goes into the block, and plug the return line to find the leak? What would be a good pressure to set the regulator on my air compressor at?

Could it simply be wet stacking from too much idling? I let it idle when I cut up my hitches, sometimes it takes 10 to 15 minuets, and I warm it up in the winter for a bit also. Just sold a machine, so I am running this one again, just noticing the issue now, and have not run it much sense the winter, except moving it around the landing.

Any help would be great, I was going to talk to my skidder mechanic, but I figured I would start here first.
THANKS!!!
Husqvarna ~ TimberJack ~ Dodge Cummins

Spartan

The fuel pump should have a weep hole on the bottom side about a half inch to inch out from the mounting surface.  It is actually between 2 oil seals.

Mine has threads so it can be plugged, make sure yours is not.  Simple to remove the pump to check condition.  I would say if the weep hole is open and not leaking, look elsewhere.

Those jumper lines can be quite finicky.  Did you run it with the valve cover off? (maybe you already have)  But I wouldn't go just by inspection.  I had to replace one and tighten a few others. Spray some cleaner on the line connections Or wipe them down, then let her scream.  Messy but you will see if they are leaking.    The flares may not be seating properly either, and it may have nothing to do with a crack.

Cracked fuel galley in head or bad rings could be other culprits but not near as likely.  I think a leaky injector would show up in a poor running condition like you said.

Maybe others will chime in.

danbuendgen

Thanks for the reply. When I had the cover off, I did check all the jumper lines, and they were tight. I wondered if I could have the cover off and start it up....but chose not to. I figures it would get oil all over, and I didnt want to have some dirt or crap drop in. We are having rain on and off all week, I will remover the cover, and try running it and see what happens. By "let it scream", do you mean to run it wide open with the cover off???
Husqvarna ~ TimberJack ~ Dodge Cummins

Spartan

It will not spray as bad as you think.  But yes you will get oil on stuff.  Not going to hurt it to rap it up in rpm.  Just grab the rack and turn it with your hand, and you can shut it off that way too.  I wouldn't write the jumper lines off until you run it with the cover off.  Most of the cracks in the lines I have seen are at the flange on the flare surface (under the nut).  You can tighten them all you want and it will not help, just make it worse.   Just my 2 cents. 

danbuendgen

I will give running it a try with the cover off, when I know it wont rain. I will try it tomorrow and report back. Good thing is if its a jumper, those are only 3 or 4 bucks, and my local TJ guy should have plenty of them.
Husqvarna ~ TimberJack ~ Dodge Cummins

treeslayer2003

almost every time that is a injector line leak. can also be one of the fittings in injector or head. wipe it all off and run with out the cover to find it.

lewis

you can pressure the system up with a cat type hand prime pump this is how I check fuel jumpers in a Detroit,most likely that is your problem,they usually leak around the top of the flair nut

danbuendgen

Husqvarna ~ TimberJack ~ Dodge Cummins

cuznguido

When you find the leaky line and replace it, resist the temptation to over-tighten the new one.  That is almost always the reason for the crack.  They require very little torque to seal.  I would highly recommend using a torque wrench with an extension and crow foot socket/wrench.  Don't recall the torque but it is not much.

danbuendgen

So we ran it with the cover off, and did not see anything obvious. After running for 5 plus minutes, some of them started to show a tiny bit of moisture. I thinks its fuel, not oil. Because it was not black it was clear. Some of them just looked "damp". There was no fuel coming off the top of the injector line. It seemed to seep out from the threaded ends.... I changed all the lines to be safe. They were only $4 each.

I also checked the weep hole on the pump and it is not blocked and it is dry.

I hope the lines do the trick. My skidder mechanic feels sure that is the issue. He did say on a very rare occasion an injector can crack, and those are harder to see, as they are covered in oil.

I also asked him if this could be from wet stacking from more winter idling, and he didn't seem to think so. When he used to log with old timberjacks, he said they never shut the skidders off until the end of the day, and only once in all the years did a motor get fuel in the oil from wet stacking, because a new guy was running the machine and lugging it down and pulling hitched at 1/4 to 1/2 throttle. He said with a DD run em wide open. Which I do anyways...

I am changing the oil tomorrow, and will keep an extra close eye on the oil level. Thanks for all the help!
Husqvarna ~ TimberJack ~ Dodge Cummins

Spartan

Quote from: cuznguido on June 06, 2016, 08:00:52 AM
When you find the leaky line and replace it, resist the temptation to over-tighten the new one.  That is almost always the reason for the crack.  They require very little torque to seal.  I would highly recommend using a torque wrench with an extension and crow foot socket/wrench.  Don't recall the torque but it is not much.
I had the opposite experience.  Put a different line on to fix a leaky one and snugged it up.  Had more fuel in the crank case after the fix than before.  Pulled the cover again and the line that I put on was leaking on the other side.  Had to reef on it to stop the leak. 
Go figure...

BargeMonkey

 It's uncommon but I've seen a hole in the injector body which dribbled fuel into a cylinder. Had issues with a 671 a few months ago with 2 leaky jumpers, 90% of the time that's your issue.

danbuendgen

Thanks for all the help. I will keep close eye on the oil level. How long would it take to have engine damage with fuel in the oil? I hope this has not taxed the motor to hard...
Husqvarna ~ TimberJack ~ Dodge Cummins

Spartan

Detroits are pretty dang tough.  We have a Pacer grader with a 4-71 that has a crack in the head.  Always has fuel in the oil.  For years.  We don't use it every day but it's still screaming.
I wouldn't worry too much about it.  I would think you would have to run it that way a long time to do serious damage.  You seem like a meticulous guy so I would think you are ok.

ohiowoodchuck

I saw a injector body crack on a duramax before and it filled the crankcase full until diesel fuel was dripping out of the oil dipstick and after fixing the problem and changing the oil it was fine. If it was antifreeze, it could be a concern but small amounts of fuel, I wouldn't worry.
Education is the best defense against the media.

danbuendgen

Ok good to know.
Just changed the oil and we will see if I have it figured out. Oil pressure was much better with good fuel free oil. A lot of guys hate the old DDs, but I like it more then the 4bta Cummins, I had a Cummins in a Franklin Forwarder, it was ok. But the DD started, ran, and pulled better. And never gelled up. The DD warms up the fuel, in winter the winter the fuel tank would melt off snow and ice. The Cummins fuel tank would be all snow and would gel up all the time, with the same fuel as the DD. Thanks for the replies!
Husqvarna ~ TimberJack ~ Dodge Cummins

danbuendgen

So far so good, been checking oil like crazy and have put some time on it, and no fuel that I can tell yet in the oil.
Husqvarna ~ TimberJack ~ Dodge Cummins

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