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Engine Oil - A slippery subject Part 2

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  • shiposhipo Member Posts: 9,148
    Ahhh, Hannibal Smith, my hero. ;)

    Best Regards,
    Shipo
  • jeffyscottjeffyscott Member Posts: 3,855
    40C is 104 F, that is about the hottest it has ever gotten here.

    But wouldn't it be obvious that viscosity of a 0W-40 and a 10W-30 have to cross? The OW means a lower viscoity than 5W at 0C, while the 40 means higher viscosity than 30 at 100C...so somewhere between 0 and 100C they would have to cross.
  • shiposhipo Member Posts: 9,148
    It seems obvious to me, however, the question is where?

    Best Regards,
    Shipo
  • wtd44wtd44 Member Posts: 1,208
    That's easy! The two curves always cross at 5252 rpms. Errrrrrrrrrrrr... whatever! :P
  • wlbrown9wlbrown9 Member Posts: 867
    40C is 104 F, that is about the hottest it has ever gotten here.

    I've seen it as high as 108 F here in Memphis, but my Trooper thermostat lets the coolant go up to maybe 195-210...I forget what the setting is :-). As long as I don't have to idle in traffic, it seems happy at that. I do remember one time it got cold enough that my old Datsun Z with weak coolant had some issues with getting up to temp until I refreshed the coolant.

    BTW, to add something worthwhile to the oil discussion, I had several scares this past fall of dropping oil pressure. At first I thought I was getting a little low, but not off the stick and would get drops down from the normal 80 psi indicated on my guage to maybe 20-30 psi range. I was running Valvoline 10-30 as per standard recommendation, usually change every 3-4K miles at Jiffy or VIOC. One note is that I was topping off with Phillips 10-30 synthetic blend (whatever they call it) instead of the Valvoline. I wonder if that has having some sort issue with mixing the 2 oils?

    It almost seemed at times it would drop to lower than normal pressure for a few minutes, then I would almost feel a little surge and it would pop back up to normal...might have been feeling things. Thought I was in for a dead engine, oil pump, whatever.

    I changed oil and filter going with Valvoline 10-40. About a week after that I took the Trooper on the annual golf trip to Destin area...500 miles hwy driving so it really got up to operating temp and stayed there for 6-8 hours each way. Since taking the trip and changing to 10-40 I have not had the pressure drop down nearly that low, idle looks to be at least 50 psi if my guage is accurate.

    So, I really don't know what has happened, but it is looking better so far. Wondering if I was getting some sludging (combination of synthetic blend and dino oil perhaps) and the extended trip at temp helped clear it out? Just glad I did not have to resort to major surgery or replacement as I was seriously considering. In some ways I would like a new vehicle, but I guess I'm wondering why to turn loose of $20-35K if I don't need to. The wife has a newer vacation capable vehicle that fits our needs and the Trooper gets me around to work, golf, etc.

    Anyway, I have felt the fear of dropping oil pressure and it is not fun.
  • blufz1blufz1 Member Posts: 2,045
    I think the higher oil pressure is just a reflection the thicker viscosity oil. (10-40 vs. 10-30).
  • lucas8lucas8 Member Posts: 15
    What dangers, if any, are there in switching from conventional to synthetic and back to conventional?
    Lucas.
  • shiposhipo Member Posts: 9,148
    No dangers what-so-ever. Switch away! ;-)
  • tedebeartedebear Member Posts: 832
    I've read stories where people said they started getting leaks if they ran synthetic for a long time and switched back.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    NAHHHHHHHH :P
  • shiposhipo Member Posts: 9,148
    "I've read stories where people said they started getting leaks if they ran synthetic for a long time and switched back."

    Old wives tails. ;)
  • lucas8lucas8 Member Posts: 15
    amazing how the same day I post the above inquiry, my buddy ostensibly floods to some degree his engine with motor oil. What do you guys think about this: My buddy checked his oil for no apparent reason, realized the dipstick read nothing, and so for some reason I can't comprehend, decided to add 3.5 qts to it, resulting in a read of about a qt over full. He drove it back 20 miles to town (against my advice, but the past is past), restarted it again to move it a few feet to a better lit place, and went to get some oil and filter to begin an oil change. We tried to start it again to get the oil flowing well for the change, but it wouldn't start. It turned over, but wouldn't catch, which leads me to believe that the spark plugs are oiled up (4 in the morning + stupid toyota valve cover without the necessary tools to take it off = no definitive diagnosis). We left the car for now and are not sure what the next course of action should be. Suggestions?
    For the record, he just got the car a week ago (2000 Avalon with 120k miles), and hasn't ever checked the oil. Nothing's coming out of the tailpipe, which leads me to believe that he's not burning anything he's not supposed to be. Also, he said that when he checked the dipstick before the whole adding oil fiasco, smoke (but probably steam, I imagine) was coming from the dipstick holder. Moreover, in the dark, the engine bay looks fine, but smaller cracks, if apparent, could easily have been missed.
    Lucas.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yeah just drain the oil and clean the spark plugs. I don't see how one quart over could really hurt anything. The "no start" might even be a co-incidence....unless he really put a LOT more than 1 quart over.
  • lucas8lucas8 Member Posts: 15
    thanks, mr, shiftright. It didn't seem to do any damage to his car after all.
  • rhmassrhmass Member Posts: 263
    Mr. Shiftright, I thought overfill by a quart of oil will actually damage the engine by whipping the extra oil into foaming, thus depriving the engine from being lubricated from what I read. Was that true or was it one of the old wife's story such as synthetics cause leaking due to the hardening of seal by the mineral oils previously used?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Oh you mean cavitation. Sure that can happen but you'd need a lot more oil than one quart overfill.
  • seltene531seltene531 Member Posts: 4
    It is fine to switch from conventional (organic) to synthetic oil. The oppsite of this will cause seepage of oil through the engine oil seals.

    Use Mobil 1 synthetic. There is no better protection out there.

    (Audi...riding the wave the others have not caught yet.)
  • jeffyscottjeffyscott Member Posts: 3,855
    Why would conventional oil cause seepage only after using synthetic?
  • shiposhipo Member Posts: 9,148
    "It is fine to switch from conventional (organic) to synthetic oil. The oppsite of this will cause seepage of oil through the engine oil seals."

    Ummm, no, that is completely incorrect. You an switch back and forth between conventional (Group II), wannabe synthetic (Group III), and true synthetic (Group IV) to your heart's content and never cause a any "seepage" at all.

    Best Regards,
    Shipo
  • jeffyscottjeffyscott Member Posts: 3,855
    Well, about a month after the switch to 10w-40 synthetic, my kids oil pressure problem seems to be back and much worse. Previously the light had only come on once or twice at 2000ish rpm, now he has said it even went off at 3000 rpm, with the car warmed up. I told him to stop driving the car.

    In January, when the technician had tested the oil pressure, before changing oil, he found it to be just a bit low at idle and that it went up as soon as rpms increased.

    Since the problem has worsened so quickly, he (my son) is now speculating that maybe the oil pump is the problem, after all.

    The shop that checked his pressure before, indicated they will check it again, without an additional charge, to see what is going on now. The owner of the shop said the same sort of thing as you, that even if the pump is bad it may not pay to replace it if the low pressure has resulted in escessive wear.
  • shiposhipo Member Posts: 9,148
    Thanks for the update.

    At this point it's sounding very much like a pan-drop type of an operation regardless of what the problem is. My personal bet is either a clogged screen or the oil pump.

    Keep us posted. ;-)

    Best Regards,
    Shipo
  • jeffyscottjeffyscott Member Posts: 3,855
    To our surprise and delight, it may have just been the sensor (they called it oil pressure "switch"). Apparently the actual pressure readings are now normal, even at idle. Previously, with the old oil he had said it was marginally low at idle.
  • shiposhipo Member Posts: 9,148
    Cool! I bet that's a load off your mind (not to mention your wallet) to have that problem fixed so easily. ;)

    Best Regards,
    Shipo
  • jeffyscottjeffyscott Member Posts: 3,855
    Yep, went from wondering what it might cost to put a used engine in to a bill for 21 bucks.

    It'd be my kid's wallet...but we did feel bad about this happening with his first car, that he has $3500 invested in so far, after 6 months of ownership. I felt particularly bad, since he relied, to some extent, on my vehicular judgement in selecting this car.

    I did run across some interesting viscosity info, as I was researching the possibility of putting _W-50 in to see if that would help. It seems there is some variation in viscosity at engine operating temp, based on the figures that are reported at 100C.

    Some examples:

    Castrol Syntec 5W-50 is 17.4 cST @ 100C, while the 20W-50 is 19.7 cST
    For Penzoil 5W-50 is 17.8 cST, while 15W-50 is 21.4
    Then there was a Kendall blend that reports 19.6 cST for a 10W-50

    Now I don't know if 4 cST would be considered a significant difference in viscosity, but it does represent nearly a 25% difference. I was surprised to see that much variation in oils that one would think had the same high temperature viscosity.
  • blufz1blufz1 Member Posts: 2,045
    Good for you,Jeffy!
  • wtd44wtd44 Member Posts: 1,208
    Those lying sensors will get you every time!
    :P
  • jipsterjipster Member Posts: 6,296
    Those lying sensors will get you every time!

    Sensors should have a sensor to let you know if they are operating correctly.
    2021 Honda Passport EX-L, 2020 Honda Accord EX-L, 2011 Hyundai Veracruz, 2010 Mercury Milan Premiere.
  • blufz1blufz1 Member Posts: 2,045
    That makes a lot of sense.
  • texasestexases Member Posts: 11,107
    Glad that was the problem - I was going to suggest that, had the same exact thing happen to my GTI - scared the ... out of me, but just one of the two sensors was bad, IIRC.
  • jeffyscottjeffyscott Member Posts: 3,855
    Unfortunately it was not a sensor problem after all.

    Now have a guage on the car temporarily, but this time the shop did see the pressure near the second sensor (which they were previously not aware of) drop to 0 after car had warmed up. So we are being told this confirms the problem is engine wear as pressure drops only when car is fully warmed up and comes right back when increase revs.

    The current oil is Mobil 1 10W-40, which has viscosity of 14.7 @ 100 C. The highest available viscosity I have found is a Pennzoil 15W-50, which is 21.4. Might this be enough of a difference to maintain oil pressure?

    We do have it on the schedule at a tech college for a mid august to mid october class. If the engine last until then, he can get repairs done for the price of parts. If a higher viscosity oil (or some viscosity increasing additive) will not be enough to limp along until then, I am going to suggest that he just park the car for the next 5 months. The only other reasonable option would be to drive it until engine is shot and then have a used engine installed.
  • texasestexases Member Posts: 11,107
    the shop did see the pressure near the second sensor (which they were previously not aware of) drop to 0 after car had warmed up

    Sorry to hear that, sounds like you do have a problem. I guess thicker oil might help, but not much, and not permanently. I wouldn't trust it.
  • shiposhipo Member Posts: 9,148
    I've been kind of suspecting loose bearings has been your problem all along, I used to run into this lots when I turned a wrench in SoCal back in the 1970s. A couple of points (in no particular order):

    1) Oil flow is what lubricates engines, not oil pressure.
    2) Engines suffering from this type of low oil pressure can run for great distances without failing.
    3) I've found that by replacing the engine bearings (both rod and main), the oil pressure can be brought back up to normal levels.
    4) With a little jockeying, most engines can be lifted just enough to allow removal of the oil pan. If this particular can be made to lose its pan, you can replace the bearings with the engine still in the car for relatively low cost (especially if you do the work yourself).
    5) If you do decide to take a shot at doing this, an aid to help you determine whether you need oversized bearings is this: http://www.plastigaugeusa.com/
    6) If you decide to run'er till she drops, BMW dealers sell a Castrol 10W-60 that is used in many of their "M" series cars. It ain't cheap, but it's plenty thick when warm.
    7) IIRC, you mentioned that the engine itself seems to run well and doesn't use much oil. Before you embark upon engine surgery, you might want to have a cylinder leak down test performed to make sure everything else is operating well.

    Please keep us posted. ;)

    Best Regards,
    Shipo
  • jeffyscottjeffyscott Member Posts: 3,855
    Thanks for the tips. I had read that typically what is worn is the bearings as you indicate, the good thing is those parts will be relatively cheap and we can get free labor next fall at the tech college. Students at this same school had worked on my Windstar a while back. They removed the engine and replaced about every gasket, plus a bunch of "might as well" stuff.

    The engine does seem to be running fine and uses no oil at all. What is a leak down test and what would that tell us? This may be something to have the tech school do, if it makes it up there.

    My understanding is the Jetta oil pan can be removed quite easily, this would be the first step if it had been an oil pump problem...and that job would have cost $350-400. Just for "dropping the pan" we were quoted under $200.

    When I searched for that BMW 10W-60, I also found it as Castrol...viscosity is 24.2 cP @ 100C. Apparently this runs about $10 per quart. I also ran across Shell Helix Racing Engine Oil in 10W-60 and 20W-60 with viscosity of 23 and 24.
  • shiposhipo Member Posts: 9,148
    A leak-down test is kind of a fancy compression test, just far more telling. Here's a pretty good write-up: http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm

    Good news about the pan drop on the Jetta, that should make things pretty easy to get to the bearings. ;-)

    Keep us posted. :shades:

    Best Regards,
    Shipo
  • wtd44wtd44 Member Posts: 1,208
    Good luck for getting in the school program a second time, and no matter what happens, let us all know how it turns out. :shades: May the future be so bright that you have to wear shades!
  • jeffyscottjeffyscott Member Posts: 3,855
    On another forum here someone posted:

    Around 2000, Ford (and perhaps, Honda) changed the engine oil specification from 5W-30 to 5W-20 for many vehicles. This was done without any actual engine mechanical changes. The reason was to improve fuel economy...

    Is this correct and if so does it mean that you would improve your engine's longevity by using 5W-30 even though the manufacturer specifies 5W-20?
  • wtd44wtd44 Member Posts: 1,208
    I have noted that in some owners manuals it says that 5W-30 is acceptable under circumstances where 5W-20 is not available. I feel that this says it all-- you can use either grade of oil without ill effect, other than gas mileage. And to top that off, I've seen dealerships put in 10W-30 (according to the billing records generated for the customers!). However, I have gotten accustomed to the 5W-20 and just stick with it. I change oil and filter at 3K intervals, so my oil doesn't have a lot of stress put on it. To each his own, I suspect. Then, there's the warranty consideration...
  • richardsonrichardson Member Posts: 92
    Shipo;

    Thanks for the trip down memory lane regarding http://www.plastigaugeusa.com/.
    The last time I used that product was when I replaced the rod bearings on my 51 Plymouth just before graduating from HS in 62.
  • shiposhipo Member Posts: 9,148
    Yeah, it's been a while for me too. I'm thinking that the last time I used it was in a 383 that I did the rods and mains on while it was still stuffed in a 1970 Challenger (the owner ran it low on oil but managed to shut it down before spinning any bearings). Geez did that job suck. :P The good news was that the car was still running some 40,000 miles later when I moved away from San Diego and changed my career from turning wrenches on cars to tickling keys on computers. ;)
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    I was chatting with a friend who, among other things, is an expert Porsche engine rebuilder and Porsche/Audi technician.

    He was of the opinion that extended oil changes get rather risky over time, because as the oil nears the end of its supposed extended oil change cycle (let's say 10,000 miles), it returns to its "base stock"; so in effect if you are running 5W-30, at the end of your cycle you are really running 5W oil on cold starts. Not so good.

    Any opinions about this?
  • wtd44wtd44 Member Posts: 1,208
    Then he must have been predicting the breakdown of the elastomers that provide the 30 weight effect when the oil is hot. Wouldn't the 5 part still be somewhat okay at cold startup?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Well sure the 5W would be okay at cold start but the theory is that it would not change viscosity as the engine warmed up. I didn't really phrase it right--what I meant to say was that "running a constant 5W THRU cold start to operating temperature is not so good".

    Also he's used to dry sump engines with huge oil capacities, so maybe that has something to do with his concerns.
  • texasestexases Member Posts: 11,107
    I've heard about the additive degradation problem, but also that newer oils are better, how much I have no idea...
  • shiposhipo Member Posts: 9,148
    I think he's completely not understanding how synthetic oil works.

    A few points:
    1) I use Mobil 1 0W-40, and if your friend was to be believed, my oil would effectively be a 0W after my normal ~11,000 mile OCI.
    2) Per my most recent 11,500 mile UOA result, the Mobil 1 0W-40 sample that I sent in came back with a comment saying "The viscosity measured in the correct range for a 0W-40..."
    3) Unlike conventional oil, the full synthetic oil that is approved for use in Porsches (Mobil 1 0W-40 being one of the approved oils) doesn't use any viscosity improvers to enable the multi-grade rating. How can that be? Simple, the PAO base is so stable that it naturally exhibits multi-grade tendencies in that it doesn't thicken as much when extremely cold, nor does it thin as much when at operating temperature.
    4) My bet is that your friend is telling you what he believes to be true, however, he has zero science to back up his beliefs.

    Best Regards,
    Shipo
  • jeffyscottjeffyscott Member Posts: 3,855
    Looking into the world of additives, I ran accross a couple items that stated that many of these are just 50 wt oil with additives. This made me wonder if oil pressure could be increased, by adding some heavier oil? Would adding a pint or so of, say, straight 60 wt oil to the 5 quarts or so of Mobil 1 10W-40, that are in the engine now, be likely to create problems?

    My kid did some testing with the temporary oil pressure guage on and he found pressure was okay until the water temp got to within about 10-15 degrees of the normal fully warmed up temp. Based on this and some straight-line interpolation of viscosity numbers, it may be that a _W-50 (or _W-60) will be enough to keep the light off...or at least it will come on less often.

    Also my thinking is if the pressure loss is that intermittent and infrequent (only at idle and only when engine is hot), it's likely the parts are still remaining pretty well lubricated, since the oil that is on the parts would not disappear the instant that pressure is lost.
  • texasestexases Member Posts: 11,107
    You sure have some confusing symptoms. The few cars I've experienced with low oil pressure from worn out bearings, etc, were pretty much low all of the time. Makes me wonder if there might be a problem with the high oil pressure relief valve - don't VWs have that? Maybe the spring is weak?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    yes it is probably more perception than science---but then, understandable in a way. I often here more cautionary tales from people who deal in $15,000--$30,000 engine rebuilds than one might from someone selling Chevy crate engines for $3,500 out the door. Greater risk often induces greater cautionary procedures I guess.

    Also the Porsche requires periodic services that seem to work against extended oil changes...more like "well as long as the car is up on the rack for its major service, why not?"
  • roadburnerroadburner Member Posts: 18,324
    I agree with Shipo. He's seen the Mobil 1 0W-40 UOAs from the M54 motor in my wife's X3. For some reason that particular engine depletes the additive packages in less than 9000 miles, yet the viscosity remains within spec.

    Mine: 1995 318ti Club Sport-2020 C43-1996 Speed Triple Challenge Cup Replica
    Wife's: 2021 Sahara 4xe
    Son's: 2018 330i xDrive

  • shiposhipo Member Posts: 9,148
    "Also my thinking is if the pressure loss is that intermittent and infrequent (only at idle and only when engine is hot), it's likely the parts are still remaining pretty well lubricated, since the oil that is on the parts would not disappear the instant that pressure is lost."

    I think that it is important to point out that just because you have low oil pressure, that in no way means that you have low oil flow.

    Question: Does your car have an oil filler hole that allows you to see part of the valve train?

    If it does, what do you see when you open it up with the engine up to operating temperature and at idle? If you see oil splashing around, then I'm of a mind to say that you needn't worry, however, if it's dry up there, then discovering the source of your problem might be worth the effort, especially if the car spends a lot of time idling.

    Best Regards,
    Shipo
  • shiposhipo Member Posts: 9,148
    And another thing! :surprise:

    I just ran across the numbers for the "new" Castrol Syntec 20W-50; apparently at 100 C it has a cst of a whopping 19.7. You might want to try and get your hands on some of that stuff. ;)

    Best Regards,
    Shipo
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