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Addressing 6.2L Oil leak(s)

Discussion in '1982-Present GM Diesel' started by B.barket, Dec 30, 2016.

  1. diesel4me

    diesel4me 1 ton status Premium Member

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    I'm tempted to put a quart of Lucal "oil stop leak" goop in my engine,or the plain Lucas oil treatment--but I'm afraid it'll be like mud in sub-freezing temps--it has a hard enough time cranking over with just straight 15W-40 in it..especially with the two batteries that have been in it 13 years and are now failing..

    Last year I was losing enough oil from the leaky pan and wherever else ,that I was adding a quart every 50 miles or so...

    I began using oil drained from cars out of my friends used oil barrels at his shop,I couldn't see spending 5 bucks a quart daily,just to piss it on the ground..--most of the cars he does oil changes on used synthetics (BMW's,Mercedes,etc)..the oil was a mixture of all different viscosity,like 5W-30,10W-30,and probably more synthetic than conventional...
    My oil pressure was lower running it on that stuff-in fact, in hot summer weather the gauge showed only 10-15 psi at idle when I'd normally see 25-30 psi-but it started a lot easier in the winter,being thinner,and the engine seemed a lot quieter too...as soon as I got the leaks to a minimum I changed the oil back to 15W-40 and it now cranks over like its grease in the crankcase first thing on a frigid morning again..and sounds like every moving part is too small for the holes they fit into for a good 10 minutes or so..:eek:..

    I'm going to have to leave the battery charger on the truck this weekend--lows near 10 degrees and 25 by day,with 6-12" of snow expected Saturday night--getting 2-4" as I type this now...looks like I'll have to go put the plow on it later..:(...hate snow!..:mad:..
     
  2. B.barket

    B.barket Registered Member Premium Member

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    ^^ I hear ya' on hating the cold!.. As I get older my tolerance and patience for it is less and less.. I love to play in the snow on my terms.. Skiing, sledding, even just bein' outside on a snowy day can be enjoyable.. But working and living your day to day life in it certainly can be a challenge at times.. Heck, I'm dying to tear into this little valve cover project but its just to damn cold right now.. My shop isn't insulated whatsoever so warming it up really ain't an option.. Does the Lucas "oil stop leak" and products like it really work?.. I don't think I'd use any as I won't be driving the truck again until spring.. Just curious about how well they work since you mentioned it..
     
  3. campfire

    campfire Adventure is out there! Premium Member

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    Bob, my Suburban popped off at 10 degrees this week after sitting for months. That's running 1 quart of standard Lucas oil treatment in the pan. The leaks slowed and the oil did thicken. On my TinyCar I have taken it too far, running 30 and 40 wt. in the summer and not swapping it out fast enough in the winter. Slow cranks and a couple second wait for oil pressure on a bitter cold morning. So you can overdo it if you're running sludge. For this first oil change, I'm running normal 10w30 in the Blazer, and it is quite happy in the cold compared to the 10w40 trucks. Don't remember if I put Lucas in there or not.
     
  4. campfire

    campfire Adventure is out there! Premium Member

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    FWIW, adding Lucas to my little Saturn slowed my leak rate from one quart every 1000 miles to one quart every 2500 miles. Not eliminated, but slower than it had been. Later the 30 and 40 wt. oils got really cheap and it made more sense to let it leak at a medium rate with the super cheap stuff. YMMV.
     
  5. longbedder

    longbedder 1/2 ton status Premium Member

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    I have a truck that liked to mark its territory. While I'm fine with establishing a little dominance, it got annoying cleaning the driveway when I went to sell our house. A pressure washer is no match for a couple years of used Delo 400 :deal:

    Anywho, over the years I discovered the following:
    -An injection pump leaking out the throttle shaft will send diesel fuel into the valley, which will then flow down and collect crud from the engine and bellhousing then drip - it looks, feels, and smells just like an engine oil leak. It also really means it's time to rebuild your IP :doah:
    -The rear main seal for the 6.2 is an old-school hemp-rope type, and it will leak. Replace it with a Fel-Pro neoprene seal (PN: BS40529).
    -When you replace your rear main seal, ditch the oil pan gasket and just use The Right Stuff to seal both the rear main seal to engine block, as well as to seal the pan itself. Put a new oil pump while you're in there because [Why Not?]
    It'll also give you the opportunity to see if your block has the infamous main bearing web cracking.
    -Oh, and while you've got the pan off, you may as well pull the front covers and put a new timing set, water pump, and crank seal on also...amiright?

    [​IMG]

    Did all that a few years ago and not a drop since.
     
    tRustyK5 likes this.
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    My 6.2 failed to start last Sunday,after we got about 14" of snow with deeper drifts--it cranked over and "almost" fired up,then the batteries started dying and it wouldn't crank fast enough to get it started..

    I didn't bother taking the snow or the tarp I draped over it off,figured it was futile to try jump starting it with two other half junk batteries I keep around for starting my garden tractors..ended up using a tractor with a snowblower to clear the entire 110 x 30 foot "Y" shaped driveway--which took 5 hours,in the 5 degree cold with gusty wind chills..

    Yesterday when I awoke at 6 am,the driveway was BARE,and it was 55 degrees all day--and it is 60 here now!..wasted all that effort and a 20 dollar V-belt for the snowblower,just to have it melt 3 days later--but if I had left it,you can bet more would have fallen..

    Before I'd do all that to stop the leaks on my 6.2--replace the oil pan,the valve cover gaskets--put in an oil pump "while I'm in there",and fix all its other things about to fail,(and God forbid I'd ever need to mess with the injector pump,etc !)----I'd just put a gas engine back in it--be cheaper and I'd like the truck a lot more...then it might start with no hassles in the cold..and not leak..

    This diesel has been put thru hell even before I got it,(was a salvage yard replacement of unknown mileage or vintage)--and I'd hate to spend a nickel fixing it when it may well have cracks,or other big problems brewing inside it..I'm just going to keep it full of oil,run it,and hope it holds together awhile longer..

    My driveway has been ruined in a few spots due to leaking oil and ATF,gear oil, .from several vehicles.

    I used a 3500 psi pressure washer once to try and wash the oil off,and the top layer of asphalt blew off with it...some spots went right down to gravel!.:eek:..would have been better off to either left it alone,or poured gas on it and lit it up,and let it burn...I tried that in other spots and it worked better than I thought!..
     
  7. B.barket

    B.barket Registered Member Premium Member

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    Thanks for this post.. That's a simple and very comprehensive list of what to do to go after the leaks plus a few other things to consider dealing with while you're at it!
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I did most of that with great success. I also took some time up top. I added a rebuilt IP and rebuilt injectors. This necessitated intake removal, which led to gasket matching the intake with a die grinder, and bead blasting the rest. The casting accuracy on these intakes is terrible, FYI. Then I did valve covers.

    The thing is, you're opening a can of worms. Where do you stop? Ideally you pull the engine and transmission, power wash the whole thing, then dis-assemble and reseal everything, then re-install. :dunno:
     

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