[NA]Car engine oil

Discussion in 'Hangar Talk' started by Let'sgoflying!, Feb 1, 2020.

  1. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    I have notes from a past mech, for my (2003, 240K mi) Tundra to use non-synthetic oil.
    NAPA-dude wants to sell me synthetic-blend, says that’s as close to non-synthetic you’re gonna get.
     
  2. SoonerAviator

    SoonerAviator Final Approach PoA Supporter

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    #1. I can’t imagine why your mechanic would want you to use only conventional oil over synthetic. They both have to meet a spec for viscosity and such, so I doubt the engine would notice as long as it’s the proper weight/viscosity. The primary difference is that the synthetics don’t break down as quickly as conventional which means longer oil change intervals and typically less chance of deposit buildups.

    #2. Has the shop guy never heard of Castrol GTX or any number of other conventional oil brands?
     
  3. SCCutler

    SCCutler Administrator Management Council Member PoA Supporter

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    I believe in using exclusively full synthetic oil in my car engines.

    What does the manufacturer say?

    Castrol 5-30 synthetic, 5 quarts for $25.00 shipped, Amazon.
     
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  4. Huckster79

    Huckster79 Cleared for Takeoff

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    I use full synthetic as well but on a high mile engine that doesn't require synthetic you are likely to get less leaks with conventional is my understanding of it...
     
  5. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Mobil says on their site to use caution switching from conventional to synthetic (reduced change interval for a while).
     
  6. Let'sgoflying!

    Let'sgoflying! Touchdown! Greaser! PoA Supporter

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    Edge or Magnatec? ($25 v $18)
    or maybe their "High Mileage"?
     
  7. -KLB-

    -KLB- Pre-takeoff checklist

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    There are generally more/stronger detergents in synthetics, so a badly sludged motor will get that crud broken up and into suspension. Better to change more often while that is happening.
     
  8. Tom-D

    Tom-D Taxi to Parking PoA Supporter

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    My new Jeep calls for a full synthetic.
     
  9. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

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    Use mobile 1 extended performance in all the cars. $28/5qt jug at wally world
     
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  10. Ravioli

    Ravioli Final Approach

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    Speaking of car oil and oil changes...

    For those of you who change your own AIRCRAFT oil, you cut the filter to check for metal, send off a sample for analysis, right?

    Do you do that with the car as well?

    [Note: I don't change the car or airplane oil myself]
     
  11. 455 Bravo Uniform

    455 Bravo Uniform En-Route

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    Not sure if it’s the detergents, but the result is correct.

    I took a 110k turbo V6 Buick that had conventional oil all its life, switched to synthetic and changed oil 3 times over a 3k mile period, because I kept opening the engine to make tweaks (oil pan gasket replacement, valve spring replacement, and oil pump mods). First oil change after synthetic was nasty. Last time I opened the engine, it was spotless, zero sludge, no exaggeration. Mobil 1. 1999-2001.
     
  12. 455 Bravo Uniform

    455 Bravo Uniform En-Route

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    Yes.
    No.
     
  13. cowman

    cowman En-Route

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    Sometimes on a higher mileage engines I’ve seen higher consumption rates with synthetic but normal/none for conventional. Usually the higher consumption happens between when you’d change conventional oil but synthetic isn’t due yet.

    My suspicion is it’s a combination of oil getting older and thinner plus the synthetic being more uniform in weight vs conventional but that’s mostly speculation. I have observed the result pretty reliably though.

    I say use the blend, check the level frequently, and if it’s fine then go with it.
     
  14. Radar Contact

    Radar Contact Pattern Altitude

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    Yes
    No. If my truck has a catastrophic engine failure, I coast to the shoulder and make a phone call.
    *Additionally, my trucks motor is a Duramax...not Continental/Lycoming
     
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  15. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    I’d just run conventional. It’s perfectly available and clearly has been working fine if you have 240k on that engine.
     
  16. Sac Arrow

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    Big bore truck engines seem to be less critical on oil than small, high revving car engines. Your Cummins 5.9 L diesel will probably go half a million miles on conventional oil, so synthetic is kind of overkill. On a small, high revving car or motorcycle engine? Makes a big difference in life. If you're the kind of person that gets rid of a vehicle after it's a couple years old, I guess it doesn't matter. If you run them in to the ground like I do, use synthetic.

    Edit: Agree with @Ted DuPuis
     
  17. Let'sgoflying!

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    I'm not convinced a clean engine is good or necessary. I've been presented with no evidence that clean engines live longer or work better etc.

    Also, the transition from 'sludged'....(sounds bad, but it's just goo in the recesses of the case)....to 'clean' seems to carry some risk.
     
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  18. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    The real need for synthetic oil comes on engines that have high localized stresses (pressures) and temperatures, which break down the oil. So for example my 3000GT VR4, BMW 740iL, and both the E55 and GL550 need synthetic. They’re engines that ask a lot of the oil and conventional breaks down too fast. Incidentally a similar concept applies at the turbine engine level - Mobil Jet II was fine on older engines but Shell 2380 is way better and doesn’t coke up as much. It just costs more.

    I run conventional in the Ram, Rotella 15W-40. Like Sac said, should go half a million miles like that just fine. But I do 10k mile intervals instead of the 15k recommended.
     
  19. G-Man

    G-Man Line Up and Wait

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    Shell's Rotella has always been recommended as a good high-detergent oil. Especially valuable for the first couple of shorter-interval oil changes on a new-t-me older used car.
    Plus, of course, the old trick of 'warm it up really well, add a quart of cheap ATF and let it idle for 10-20 minutes, then change the oil right away."
    I'm definitely neither chemist nor engineer, so your mileage may vary. (Get it? Mileage may vary!)
     
  20. FORANE

    FORANE Pattern Altitude

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    My Duramax runs low oil pressure at idle when using synthetic. Even trips the low oil pressure alarm occasionally on synthetic. Doesn't do it with conventional so I use conventional in it.
     
  21. Zeldman

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    My 2005 Duramax, the oil pressure is just fine at idle. I switched it to synthetic at 500 miles. How many miles on your truck?
     
  22. FORANE

    FORANE Pattern Altitude

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    05 truck with 235k but changed motor about 15k ago for a topkick Duramax motor. Not really sure how many miles on the motor but it is a beast.
     
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  23. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    That sounds like worn bearings or a worn oil pump.
     
  24. Zeldman

    Zeldman Touchdown! Greaser!

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    I gotta agree with Ted. Or possibly something not right with the sending unit.

    What is the oil pressure at normal driving speeds?
     
  25. SCCutler

    SCCutler Administrator Management Council Member PoA Supporter

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    I'm using the "High Mileage" goo.
     
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  26. pigpenracing

    pigpenracing Pattern Altitude

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    My 2002 Suburban ran conventional and never leaked a drop of oil. I put in Synthetic and it started leaving a puddle of oil under it. Two days later I put conventional back in and it has never stopped leaking. I was warned of that on older vehicles.
    That was 5 years ago and it still leaks.
     
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  27. -KLB-

    -KLB- Pre-takeoff checklist

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    In older vehicles, the natural rubber and fiber seals swelled by absorbing some of the oil, and synthetic isn’t absorbed as much in those materials, rendering a loose fit. But by 2000, that shouldn’t be a thing. It is also possible that a shaft seal had built up a layer of varnish on the shaft that the seal was riding on, and that the higher detergents took that shaft coating away, resulting in a loose fit. That could explain why switching back didn’t fix it. My 05 F150 has been on Mobil 1 since about 20,000 miles, and just within the last year has developed a rear main seal leak. Other than that, it seldom took any oil between extended oil change intervals. Not looking forward to dealing with that one. Debating actually paying someone to do it rather than deal with it myself.
     
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  28. Craig

    Craig Line Up and Wait

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    My 7.3 with HEUI injection prefers synthetic, especially in the cold. Just switched to Rotella T6, 5W-40 fr the winter and it makes a huge difference in crank times...
     
  29. FORANE

    FORANE Pattern Altitude

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    With full synthetic (5w40) after warmed up at idle it could dip to the orange line on the gauge, what is that maybe 10-15 or so? With synthetic blend or 15w40 conventional it never hits the orange line.
    When cold and when driving it is much higher, like 60.
    I have replaced the sending unit a couple of times. Just replacing the sending unit has fixed low readings on this truck before.
     
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  30. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    The 15W-40, being a hair thicker, will impact that idle reading and that makes sense. That said, I've never heard of having to replace an oil pressure sensor that many times to get a reading up. Might be a Duramax specific thing, but that does sound like worn bearings or a worn pump.
     
  31. Bill Jennings

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    I go with synthetic as two of the cars are modern turbo 4 cylinder engines. One is putting out 2hp/ci, the other 2.2hp/ci, far more than the old hot rodders goal of 1hp per cubic inch. As such, being turbo and high strung, I went synthetic at the 1st oil change.
     
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  32. kgruber

    kgruber En-Route

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    Costco now has "Kirkland" branded 5-30W synthetic oil. Something like $24 for 10 quarts
     
  33. SCCutler

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    That there is a seriously good price!
     
  34. Huckster79

    Huckster79 Cleared for Takeoff

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    I did same thing on my 04 burb but the transfer case- unknowingly. But turned out blessing in disguise. I didn’t know it had transfer case work done before and someone used the wrong sealant that worked for the 30 weight oil they put in it- I changed it not knowing they had done that and the T case fluid ate their seal!

    In splitting it to do new seal I found out about “pump tub” a real killer to that era T case - $30 fix if ya catch it before it’s too late.. check into it- pretty simple repair to a factory oversight...
     
  35. kgruber

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    Do you have a little more info on this? I have an 04' Sub, changed out the transfer case oil once, a long time ago.
     
  36. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

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    I'd love to know how good it is. Kirkland gas is Top Tier, we run it in our cars with no issues. Never hurts that the gas is far cheaper than any other top tier rated stations and and with the Costo Visa card you get 4% back on all gas purchased at Costco. That makes it even a better deal than the cheapest no name gas.
     
  37. Tom-D

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    my 2019 jeep has 8569 miles on it, the oil was changed at 5000 miles, the oil has not changed color, and still looks clear.
    should I still change it, or can continue to run it ?

    https://www.napaonline.com/en/p/NO_75521
     
  38. SoonerAviator

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    Why would you change it after 3569 miles? Are we just talking age limit since last oil change? I don't think I'd change it out unless you get to two years without getting to oil change mileage interval. I only change the oil in the boat every other year since it usually only sees 10-15 hours of run time per year; that's with conventional not synthetic.
     
  39. Tom-D

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    the plan was to change at 5k
     
  40. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

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    RTFM, what does it advise?