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Excessive oil consumption

Discussion in '6.9L IH & 7.3L IDI Diesels' started by aofarrell2, Oct 7, 2019.

  1. aofarrell2

    aofarrell2 Turbo Desirous

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    Sooo... Been burning a LOT of oil in my '92 7.3 IDI (non-turbo). I'm going through a gallon of oil every 250-300 miles, sometimes more. But it's not really smoking blue at all, and it isn't leaking more than a drop or two. Truck starts and runs decent. I've got to figure this out because it's my daily driver and I put a LOT of miles on it. The oil consumption is driving me nuts!

    Any ideas??

    I've seen some mentions of the CDR valve being a possible culprit, but could it really cause it to use this much oil?
     
  2. franklin2

    franklin2 Full Access Member

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    What type of oil are you using? I would not use any type of synthetic or synthetic blend.
     
  3. D_Fresh361

    D_Fresh361 Supporting Member Supporting Member

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    :eek:
     
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  4. Clb

    Clb Another old truck Supporting Member

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    Idi's like to drink rotella and non rated dino...
    Post more info about truck and conditions so we can help..​
     
  5. Kevin 007

    Kevin 007 Full-floater

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    I would certainly try to clean out the cdr valve or replace it. Doesnt' cost much either way and is pretty easy. Failing that, you could try a heavy dose of AutoRX or Seafoam or Marvel Mystery Oil in the crankcase and hope that helps
     
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  6. aofarrell2

    aofarrell2 Turbo Desirous

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    I run 15w40 Delo or Northland conventional oil, both are CK-4 rated oils.

    As far as conditions, oil consumption increases with engine speed. Interstate driving vs highway is noticeably different for consumption.

    Never heard of this AutoRX stuff. Where do you guys get it?
     
  7. Robert wood

    Robert wood Registered User

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    My '89 is right there with your truck in oil consumption. I go through about 1 gallon every 300-350 miles or so and it *totally* is burning it lol. I dont have mosquitoes (Michigan's state bird) anywhere near my house. I ended up having to relocate my CDR valve from behind the air filter housing to somewhere up by the fender and then let it vent into a catch can, then let that vent any pressure build-up through a jenky k&n valve cover breather/filter. Its convoluted. And smells terrible. A new motorcraft cdr valve can be had from Amazon for about $50 if I remember right, or you can go to O'Reilly's and nab one for a GM 6.2 because for whatever reason they dont carry the Ford part. Bastards.
    If you're getting oil into the intake it would be very noticeable, there would literally be an oily mess under the cdr inlet in the manifold itself.

    Sent from my LG-LS993 using Tapatalk
     
  8. chris142

    chris142 Full Access Member

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    Pull your oil fill cap off with it running. Is it puffing smoke?
     
  9. franklin2

    franklin2 Full Access Member

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    You guys are putting too much stake into the CDR valve and it's function. I am trying to remember a old post on here, I think there are several threads on it. How the CDR has only one real function, and it's not to control continuous blow-by or oil consumption or have any affect on oil consumption during normal operation.

    Someone will correct me if I am wrong, but I believe the only function of the CDR was to prevent engine run away if the intake pressure went too negative and started pulling oil and oil mist from the crankcase. Otherwise that is just a wide open hole where the blow-by from the engine just drifts into the intake stream. The CDR really can't cause more or less oil consumption.
     
  10. david85

    david85 Full Access Member

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    As far as I always heard, the CDR does affect oil consumption. It was a long time ago that I rebuilt my 6.9, but I can say that half a gallon of oil per fuelup was not unusual. The valve stem seals were cracked and dried out but otherwise, the engine pushed over 400PSI on all cylinders before the overhaul. No idea what it is now, but oil consumption is so low I hardly check it anymore. I've been running 100% synthetic for the last two changes, mostly because of the short daily commute I now have.
     
  11. 79jasper

    79jasper Chickenhawk

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    I could agree to an extent, but many have seen reduced consumption by replacing it.

    Sent from my SM-N960U using Tapatalk
     
  12. Chief

    Chief Registered User

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    I have the same issue with my ‘93 IDIT. Been through all the possible fixes including getting her hot to unstick oil rings. She’s currently parked waiting on a rebuild as soon as I have time. With that kind of consumption, it’s probably further inside the engine. Have you checked compression? Solvents probably won’t work because they won’t stay in the engine long enough to do their job. And the CDR is not likely to fix anything. Been there too. Worst case, rebuild it. Nothing like tearing into an engine and rebuilding it. At least then you know what kind of workmanship went into it.
     
  13. chris142

    chris142 Full Access Member

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    Different oil brands and weights do change the consumption in these engines. Mine has always used a at every 700 miles. I put rotella synthetic 5w-40 in it once and that was a mistake. It burned that oil so fast that I could not keep up with it. I was buying whatever oil the gas stations had every time I got fuel. Then the rear main started dumping and ruined my clutch.

    I have found that Valvoline causes the least amount of oil burning in mine.
     
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  14. Robert wood

    Robert wood Registered User

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    What weight oil have you been using, my dude? I had considered the same thing but didn't want to upset any voodoo that had been holding my truck together. 20-50w conventional?

    Sent from my LG-LS993 using Tapatalk
     
  15. nelstomlinson

    nelstomlinson Full Access Member

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    My '87 and my '94 will each burn a gallon in 200 miles.

    On the '87, I thought there might be a problem with the CDR, so I took the hose off it (it's the Banks relocated version) and just turned the hose into a downpipe. Now the engine stinks a bit more when it's running, but the oil consumption is exactly the same. Your CDR might be a cause of your oil burning, but mine definitely wasn't any part of my problem.
     
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