Oil in Exhaust

Discussion in 'Diesel Tech' started by cphmr8604, Jan 11, 2020.


  1. cphmr8604

    cphmr8604 Farmall Cub

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    So it's been a while since I've posted about my SD33 diesel on here. Life got in the way the past 6-7 years of ownership and the Scout has sat in my dad's shop unfinished in that time period, but it still drives. A couple months ago I got the Scout going and drove it up to my shop to get it finished and back on the road.

    Long story short, I was about to change the intake/exhaust gasket because it was leaking (you could see smoke blowing out the manifold area) and when I pulled the intake off, there was a lot of soot buildup and oil. I was like "That can't be right." Pulled the exhaust manifold and it was worse. There was a lot of oil on the valves. Plus, the oil is really thick and tacky. I did change the oil back when I bought it and used Rotella T 15w40. I'm hoping it's just from sitting for so long and will come out of it once the Scout is finished and gets driven more. What do you guys think?
     
  2. Joe S

    Joe S Farmall Cub

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    Soot in the intake is from the EGR and is normal. Oil not so much. There's no PCV system that might put oil vapor into the intake so the other possible source would be the TC compressor seal or maybe valve seals. Exhaust valve seals sound bad too If the oil is in the manifold before the TC.
     
  3. cphmr8604

    cphmr8604 Farmall Cub

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    Mine is a NA diesel but there's definitely oil in the exhaust manifold.
     
  4. Dana Strong

    Dana Strong Lives in an IH Dealership

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    Maybe it's largely a mixture of unburned and partially burned diesel that's oxidized, polymerized and been acted upon by microorganisms while sitting for long spells? Do you remember the engine's history/behavior before it was parked? Did it use much engine oil then? How hard is it to check turbocharger seals?
    If you add/mix in some acetone, does the pooled old oil get softer, thinner and easier to clean out?
    Have you checked the manifold and block surfaces to see if any warpage caused the gaskets to not seal well?
     
  5. cphmr8604

    cphmr8604 Farmall Cub

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    I added some diesel fuel biocide a few years ago to prevent that from happening. Plus the tank already had really old fuel in it (different story) when I got it but I purged most of it out with compressed air and put fresh fuel in since then.

    The previous owner used this Scout as a daily driver and when I got it, it had seen better days. He used ether to start it and I have installed new glow plugs because I don't like using ether.

    It would emit blue smoke at normal operating temp, which was not much above 140 because the thermostat was stuck open until I changed it to a 180. Hard telling how long it was like that.

    It has no turbo. This is a '77 Scout.

    Haven't tried that. You can add that to the crankcase without damaging the engine? Would that loosen up sludge?

    I was surprised to find the nuts weren't really tight, but I looked up the torque specs and IIRC, they said 27 ft/lbs. I'd have to look at the service manual again, but I didn't look for warpage or even thought of it. I just proceeded to clean the surfaces really good. I remember back when I got the Scout, I took my dad for a little ride in it and saw the temp rose above 230. We weren't further than a mile from home so I drove it back right quick. The radiator that was in it at the time leaked and all I saw the owner do was add faucet water to it and I was thinking he probably did that all the time which is something I frown on, but whatever. I gave less than $1000 for the Scout. However I hope he added antifreeze in the winter. Surely he knew better because it was August when I got it. But say he didn't, would a cracked block be the problem?
     
  6. scout2000

    scout2000 Dreams of Cub Cadets

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    Ouch, never good to hear both diesel, and long term use of ether together.
     
  7. Dana Strong

    Dana Strong Lives in an IH Dealership

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    Not to the crankcase, to the gooey stuff you found in the manifolds. That is, not unless you're cleaning the insides after pulling the whole engine apart and then using the solvent. Specifically ... Not running or cranking the engine with it mixed in the oil.
     
  8. cphmr8604

    cphmr8604 Farmall Cub

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    I forgot to mention the engine ran really good when I got it and it starts right up to this day. Just the inherent rough starts though. I have to plug it after it starts until it smooths out. Hardly any white smoke at all. There was a lot of white smoke when using ether but like I said, I DON'T use ether in it anymore. But if I stood on the accelerator in 3rd or 4th gear, it would blow black with a little bluish-white smoke if I recall correctly.

    When I test drove it I noticed he DID use diesel oil because there was Valvoline Blue and Rotella T containers behind the seat. He didn't say it used a lot of oil and I didn't drive it enough to really tell.
     
  9. cphmr8604

    cphmr8604 Farmall Cub

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    Ok. That clears things up. I wish I was more mechanically inclined to take the engine apart to at least get the valve guides replaced and have the ports polished. I wonder how much it'd cost to have it rebuilt because this is honestly the furthest I've ever gotten with taking an engine apart. And would it be worth it? It has to be north of $2000 easy.
     
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  10. cphmr8604

    cphmr8604 Farmall Cub

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    I was at work all weekend so I was finally able to go back to look at the intake manifold and found it was mostly coated in soot instead of oil.

    One thing I also didn't mention was at some point the oil filter housing was changed over to a spin-on type (now uses NAPA oil filter 1794 which is a pretty good sized filter) and I remember having to put 11-12 quarts in until it read full. To me that's a big capacity for a small engine. I'm reading in the service manual that it calls for somewhere around 2 gallons and I put in an extra gallon to bring it up to the full mark??? Is it because of the bigger filter??? If not, could it be why there's oil in the exhaust???
     
  11. cphmr8604

    cphmr8604 Farmall Cub

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    For anyone who comes back to read this thread may find this helpful. I talked to Super Scout Specialists and told them the symptoms and they said the thick, tacky and black "oil" in the exhaust is unburnt fuel. It makes sense because every time I've ever had it running in the past 5 years it was only idling and hardly revved up. So they said it should clean itself up once it gets driven more often. Thanks for the replies!
     
  12. Dana Strong

    Dana Strong Lives in an IH Dealership

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    So I was essentially correct above? I assume it wouldn't hurt to clean it out manually if the manifolds are already open.​
     
  13. cphmr8604

    cphmr8604 Farmall Cub

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    Yes sir you were correct. And yes for the time being I'm leaving the manifolds off because I'm trying to get the alternator lined out, but that's a completely different issue. The guy who had this before me jury-rigged so many things on it it's ridiculous. I agree the manifolds need cleaned. Clean all the soot out of the intake and get a little better performance anyway.
     

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