Heavy Equipment Forums Heavy Equipment Community

Detroit Diesel fuel in crankcase oil

Tom Spivak ยท 2008-02-19 17:15

I'm getting lots of diesel in my crankcase oil on a 3-53 detroit diesel. Injector lines are not leaking, pump seals are good, no coolant in oil, no oil in coolant. About 4 quarts every hour of run time. I shut fuel off at night. Any ideas, leaking injectors maybe? how do I test them?

Replies20
  1. #1Underdog2008-02-19 19:32

    That much fuel I would think it would have to be a injector fuel line or fitting on top of the head. Maybe a crack in the head fuel line gallery. good luck.

  2. #2dayexco2008-02-19 19:35

    detroits are a 2 stroke engine, do you have ring wear/busted ring/scored piston/cylinder wall?

  3. #3surfer-joe2008-02-19 20:58

    I hazard that you may have a bad injector assembly, maybe all three if you are getting that much overage in crankcase. Detroit injector jumper lines are also notorious for leaking, I'd take them all off and look at the flares closely for a crack, also something more common than not. Look closely at the lines just above the flares, and also right at the top of the nut, both good spots for cracks. One other possibility is the fuel transfer pump. So far as I know, all Detroit fuel pumps have a bleeder drain hole in the housing so that if the seals let go, the fuel runs to the outside, but I've seen some that had the holes blocked with dirt and baked-in crud, so fuel went the other way into the crankcase. This is one instance where you would get a lot of fuel in the wrong place in a hurry. All this said, if you had bad injectors, you likely would be getting quite a bit of blue smoke and slobber from excess fuel in combustion chamber. If one or more injector jumper lines were leaking, you might see some stuttering or see a loss of power from lack of fuel. A heat gun would tell you quickly if this were the case, point it at the exhaust manifold directly above each exhaust port. The fuel pump leaking most likely would indicate the same way, loss of power. In my experience, a cracked head into the fuel galley is quite rare though I have seen it, usually on bigger engines. The 353 is a tough little b*****d normally and I've never had much head trouble of any kind with them. If you are close to a diesel tech school Tom, take the injectors into the shop and see if the fuel systems instructor will test them for you for free, or maybe he will have one of his students do it. Most all diesel colleges have a little pop-tester on hand. Lacking that, find a diesel injection shop or rebuilder close by and get them tested there. They may have exchange units on hand to sell too. You can do a rough test by hand with the injector in a sturdy vise. Place the injector in the vise in an upright position. (try not to let any fuel drain out of the injector from removal from engine to vise) Then use your hand and press down on the top of the injector. If fuel starts dribbling out of the nozzle, you got a bad one. The fuel shouldn't come out till it hits the pop pressure, then will spray. But if the spray is ragged or globby, then you still have a bad unit. This is sort of a shade-tree method of testing, but it does give you an idea sometimes of what shape the things are in. Lastly, you may have a cracked injector body. This is very rare and about the only way to find it is to remove and test the injector on a test bench. I've seen a couple that were visible to the naked eye, most times they are not. Last resort is a Detroit dealer, more costly, but very competent. Good Luck!

  4. #4Tom Spivak2008-02-19 21:49

    The problems started with a loose hold down bolt for the clamp on the injector, I had hard starting and loss of power, then I noticed a rattle and went straight into the shop. Took the valve cover off and the bolt was completely unscrewed with the injector up abit. The sleeve was up about a sixteenth of an inch and suspecting that some special tool would be needed to reseat it and since it would not budge with farmer methods I opted for putting it back together and retorqueing the bolts. I think it may never have been in correctly.I checked valve adjustments and replaced all lines, lacking a manual or injector timing tool I restarted the engine and checked for leaking lines, with all well in that regard I changed out the oil and filters and away I went. 1 1/2 hours later I had an extra 2 quarts in the crank case. ( revised from my original post as my son has pointed out that I drained extra oil out) . Wanting to recheck this I drained it down an added two bottles of Lucas and some 40 w to get the viscosity back up, checked the fuel pump seals under pressure, and tried again with same result. I have now parked it as I am on my 3 rd oil change and it's starting to get costly not to mention the fear of further damage. I know the injector now fits loose in the sleeve but don't know what relationship that could have to fuel in oil if any, although it must be out of time somewhat it starts excellent in very cold weather and runs well. It does hesitate when under load now and previous to this never burned any oil, any loss I could atribute to drips. HOWEVER- my son says that he always thought the oil was a bit over filled. I have had this machine about 3 months and put maybe 6 hours a week on it for snow removal. I will try your injector bench test as it's the best info I have had yet on checking them. There are no schools here and we are damn short of Diesel mechanics and even our local tractor guy, who I respect, says there are no Detroit Diesel mechanics around here. Last resort is call someone in, but I'm a good mechanic and feel if I get the tools I can get a handle on this, just need to know what I'm looking for. Thanks loads, and I will report my result if a few days.

  5. #5Tom Spivak2008-02-19 21:58

    Could you give a further explaination of the heat gun test, motor running or off, what am I looking for?

  6. #6Construct'O2008-02-19 22:01

    Search out a few over the road truckers in the area and also ask them about some local truck mechanic. I'm sure there is some older truck mechanics around that could help you out.Good luck:usa

  7. #7Eric2008-02-19 22:06

    A friend of mine is having the same problem with his 60 series in his Pete. Still clueless as to the culprit.

  8. #8surfer-joe2008-02-19 22:29

    If your Detroit is running well on all cylinders, the exhaust temperatures per cylinder will all be roughly equal. This can be measured somewhat roughly with an infra-red gun by pointing it at each cylinders exhaust port area where it dumps into the exhaust manifold. If you have a cylinder running hotter or colder than the average of the others, you got a problem in that cylinder and it is likely fuel related. I knew a Detroit dealer serviceman in West Virginia that also tested this with his fingers, a practice I do not recommend, but he was from West Virginia -- what can I say?

  9. #9surfer-joe2008-02-19 22:36

    Eric, I'm not so up on the 60 series. But as they also use unit injectors with a common rail fuel galley, it's likely the problems are nearly the same as for the two stroke models. The 60 series is one tough engine. Saw one in Albuquerque one time that pulled all the way in to town from the Texas panhandle with a hole through both sides of the block and one rod busted down to nothing. No Detroit dealers in eastern New Mexico or the western panhandle and the driver said he wasn't going to stop and pay a tow truck to come get him all the way from Albuquerque. That rod just missed the CPU on the left side of the engine by about an inch.

  10. #10Eric2008-02-19 23:05

    Holy smokes that is tough!

  11. #11NW Crawler2008-02-20 02:05

    I've got a big crate of surplus detroit parts taking up space in my warehouse. If you guys figure out what you need let me know and I can check the crate. It's all new surplus stock. I know some of it is 60 series but there could be other series stuff in there as well.

  12. #12Tom Spivak2008-02-20 07:48

    I'll likely be taking you up on that offer, if you have series 53 parts. Tom

  13. #13Tom Spivak2008-02-20 08:27

    I guess the first thing I would need would be three of N45 injectors for a 3-53 Detroit and the copper sleeve kits as well. Head gasket set? Thanks Tom

  14. #14Squizzy246B2008-02-20 13:46

    Tom, Joe is on the money re the lift pump. I have come across this several times. The other thing is fuel dilution of greater than 5% runs the serious risk of a crankcase explosion. Please don't run it unless you absolutley have to.

  15. #15Tom Spivak2008-02-20 15:37

    We know for sure it's not the pump. And have just checked the return line. The saga continues.

  16. #16Ray Welsh2008-02-20 15:44

    Try running it with the rocker cover removed. It could be a hairline crack in the fuel lines which you should be able to see during operation. As Squizzy said; Avoid operation with much fuel in oil. A sump of oil is cheaper than a wrecked engine........C ya.........Ray

  17. #17Tom Spivak2008-02-20 17:18

    Thanks Ray, we already did the no valve cover thing and there are no leaks and all lines have been replaced. We're watching the oil dilution as well. Currently we are swaying toward a injector leak problem.

  18. #18Underdog2008-02-20 19:59

    I am betting it is a leaky injector. I have never heard of a Detroit blowing up from too much diesel in the crankcase. burning up but not exploding. I've run old worn out Detroit's that I swear had close to 100% diesel in the sump!

  19. #19Squizzy246B2008-02-21 04:19

    I don't know of any 53's or 71's suffering a crancase explosion but there has been some 92 and 149 series. A 149 that I investigated blew a crancase door fitting off which smashed the knee of the oiler, permanently disabling him. Google for "fuel dilution" and separatley for "crankcase explosion". Diesel talk has some good stuff too. Relatively rare in small diesel....but never take excessive fuel dilution as the norm...it aint right.

  20. #20Tom Spivak2008-02-23 13:34

    Leak has Been Found I pressurized the system and found that the injector was leaking badly in it's fit in the sleeve, now I need to know how to replace the sleeve. Thanks to everyone for their input into this tricky problem!