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GM 8.1L using up too much engine oil

woneilwoneil Posts: 8
edited March 2014 in Chevrolet
have a gm 8.1L engine that uses too much engine oil

1st 5,000 miles 1 quart of oil, 2nd 5,000 miles 1 1/2 quarts of oil, 3rd 5,000 miles 2 quarts of oil

gm answer so far is that that is acceptable

dealer admits it is a problem but hands are tied until gm comes up with an answer

last oil change switched from 10-30 to 5-30 hoping to lower oil pressure

any idea's or solutions would be great



  • vidtechvidtech Posts: 212
    i believe your change to lighter oil will cause MORE oil consumption.1 quart for every 2500 miles is not that bad.i would be concerned about the downward trend though.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    bears watching but I wouldn't be particularly concerned either. Well within specs for that engine.
  • thanks for the input
  • zueslewiszueslewis Posts: 2,353
    one quart every 3,000 is acceptable. I wouldn't worry. Now, if you owned a VW Golf, Jetta or Beetle, you'd probably be in the 1 quart per 750 club!
  • Well, my 8.l just burned a 1 1/2 quarts at 1500 miles. Also, a co-worker burned a quart at 1600 miles. This is NOT normal. My 350 engine never burned oil in my Camaro and my Extended Cab. Well, this oil consumption adds to the list of problems I had with this truck. I've had the truck 4 months and this is what went wrong with it: front 4wd came apart (unsafe to drive), heater blower motor has been replaced, passenger side seatbelt locks up (been replaced), what next! Let me know what kind of problems you all have had.

  • zueslewiszueslewis Posts: 2,353
    What state do you live in?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    There's no ONE normal number. "Normal" is a range of consumption for the highest percentage of engines of that particular type. It's like a heat gauge...."normal" is somewhere in the green, not 183.5 degrees.
  • I live in Anchorage, Alaska.
  • elderdog1elderdog1 Posts: 10
    i now have17000 plus miles on my 8.1 gmc, oil use about 1 qt 4000/5000 miles ,i changed to full syn mobil one at 2500 miles , have not had the first prob of any kind , i tow a 14,000 5th wheel, love this truck
  • woneilwoneil Posts: 8
    have not had any problems with my 8.1 other than my oil consumption, really love the truck, getting about 11 mpg around town

    like i said before i switched from 10-30 to 5-30 weight oil to see if i use less oil but only 500 miles sense i changed over so too soon to tell

    will get back to you after a few more miles

  • dinu01dinu01 Posts: 2,586
    "really love the truck, getting about 11 mpg around town" What truck is this 8.1L engine for? I'm really curious to find out. I hope it's a BIG truck, not a GMC Savana type. Let me know. 11mpg>that's not something to brag about BTW.

  • burdawgburdawg Posts: 1,524
    The 8.1 replaces the venerable but dated 7.4. It's available on 1 ton chassis (3500) GMC and chev. trucks. It's completely appropriate for the type of duty these trucks can do.
  • jgmilbergjgmilberg Posts: 872
    The 8.1L engine does replace the dated 7.4, but in reality it is still the same old big block engine with a new intake and electronically operated throttle.

    The engine is available as an OPTION in the 2500 regular duty and heavy duty Silverado/Sierra pickups, the 2500 Suburban/Yukon XL, and the 2500 Express/Savana vans.

    I am not sure if this is the base engine in the one ton trucks, but I know it's not in the vans, they still have the 5.7L as the base engine.
  • jgmilbergjgmilberg Posts: 872
    GM actually has a TSB for the oil burning issue for the 6.0L and it might help out on the 8.1L, it simply states to change the PCV valve. It's a cheap enough fix for those of you that don't want to fight with the dealer over it.

    There is also an informational bulliten from GM but the dealer has to call it in to get the full details, here is the number and description of the bulliten, you will need it if you are going to talk to the dealer, they WILL NOT offer up this info, and might not even know about it.

  • burdawgburdawg Posts: 1,524
    After jgmilberg's post I rechecked. The 8.1 is available on those models along with the 3500 series.
    As a sidenote, the 8.1 is also being used as a marine engine. I don't have any first hand knowledge of it, but I hear from other boat owners that it's considered a "throw away" engine, meaning that once the cylinder walls are worn out it can't be bored and rebuilt. Evidently the bore is already maxed out for the block.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 64,490
    There are quite a few "throw away" engines these days (from the 90s on up). You'd be surprised to see the list. If you look at engine rebuilders websites, they will often use an asterisk on certain years and models of car/truck, where they do not recommend a rebuild.
  • woneilwoneil Posts: 8
    the 8.1 does not have a pcv valve so replacing it wont work (bummer)

    not too worried about rebuilding the engine, i will have bought another truck by then, but it would be nice if i did not have to check the oil all the time

    2000 miles have gone by sense i changed the oil and i am down a quart

    this time i am not going to add any oil and see if the oil stays at the add line on the dip stick

    by leaving the oil at 5.5 quarts and lowering the oil pressure it might not use any more oil, will see (has worked on other vehicles in the past)

    and yes i will check it at every full up
  • I have a new 8.1 liter Vortec, less then 6k miles and I've had 2 oil changes (long story) and used--make that BURNED 8 quarts of oil. I have no leaks. The dealer has told me (I have it in writing) that GM Techs (factory) states that the engine will normally use 1 Quart for every 100 gallons of gas. That equates to 1 quart/1000 miles which means I'm putting in 3 quarts between oil changes????? I have a 95 Dodge Dakota(318) with 210K miles on it that uses NO OIL.
  • woneilwoneil Posts: 8
    the dealer is right

    that is what gm and the shop manual state

    1 quart every 100 gallons of gas

    if you have used 8 quarts in 6000 miles then your truck engine is considered to be using excessive oil and gm will have to do something about it

    first they will test oil level for 1000 miles and go from there

    let me know what happens if anything

This discussion has been closed.