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GM ENGINE KNOCK

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    ndahi12ndahi12 Member Posts: 235
    I agree with you
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    allchevyallchevy Member Posts: 28
    Soon I'll be in a BBB claim and the dealer thinks the GM area rep will bring another truck (I have a 2001 crew cab 6.0 liter) that has the same engine knocks and rattles.
    Anyone have a good answer for their attempt to explain away the noises by comparing to another defective engine??
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    edetoredetor Member Posts: 12
    I have a 00' 5.3 that had the cold start knock. I eventually was given a new engine after 21k miles. My reasoning for wanting a fix regardless of the "it's normal" defense was that I never had an engine sound like this before unless it had a problem such as a bad lifter. In addition, I could not in good conscience sell this truck to someone without letting them know of this noise and therefore my resale value was compromised. The new engine has about 5k w/o the knock yet and the weather has turned cold in Central NY. The BBB also got me a 6/100k zero deductible Value guard warranty.
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    l_keeganl_keegan Member Posts: 6
    My last Chevy truck was a 1995 s/b ext cab. Z71 with a 5.7 litre engine that had the proverbial startup engine knock. I complained to the dealer about it and they did some checking and finally at
    around 34,000 miles they replaced the motor. All was well for a while until the new motor did the same thing. The dealer tried several different updated oil filters to no avail. Finally they said that GM said to run it the way it was and that if it failed that they would replace the motor even after the warranty ran out.(I had and extended warranty on this truck) They even wrote it on the repair receipt so I would have the documentation. I drove the truck for a couple of more years and finally traded it. As far as I know it still is running today.
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    allchevyallchevy Member Posts: 28
    Thanks fellas for the experiences, it's going to be an easier road for me travelling with a little more confidence.
    Happy New Year!
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    eric2001eric2001 Member Posts: 482
    Give them my arguement: It didn't make this noise when new, if it did, I wouldn't have purchased the truck.

    I also mentioned: if this is normal, why don't they all do this from the factory?

    -Eric
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    allchevyallchevy Member Posts: 28
    Those are very good statements eric.I've thought the same myself.It did not make any knocks and rattles when I bought it - and I was listening for them too! Did GM give you a extended warranty,new engine,new truck or a refund? I really don't want them tearing the engine down trying to "fix" it at the local dealer.
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    eric2001eric2001 Member Posts: 482
    Warranty, which they happily obliged me with. Unfortunately I only told them I drive 12k or so a year, so they limited the warranty to 6/75 unlike others wo are getting the 6/100. BTW the warranty is the Major Guard $0 deductible, and don't settle for anything less.
    -Eric
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    PAmanPAman Member Posts: 207
    Before the meeting, go to a Chevy dealer where they don't know you, but has several trucks with the 6.0 in stock.

    Start several of them; find some that do knock and some that don't. Write down the VINs of those that do and those that don't. Take that to the meeting. Tell the arbitrator that you sampled several trucks with the same engine, some had the noise and some didn't. Provide him with the name of the dealer, the VINs of the trucks you sampled, the name of the salesman you spoke to and the date and time you were there.

    NOTHING speaks louder than verifyable evidence! If necessary, invite the arbitrator to temporarily stop the meeting, go to the dealer, start the trucks you have listed and hear the noise for himself. Then let him hear the trucks that DON'T make the noise.

    BTW, be sure and go into the meeting knowing what you want. For example, do you want a new engine in your present truck? Do you want new pistons and rings in your current engine? Do you want all of your money back? Do you want to swap even for a new truck?

    Good luck. Let us know what happens.

    Joe
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    PAmanPAman Member Posts: 207
    1. Ask several of the guys in this forum to send you the VINs of their trucks that they are having trouble with. If you have access to a fax machine, ask some of them to fax you their work orders, showing the date, name of the owner and the VIN of the truck that was repaired.

    2. Be sure and ask the GM rep how many trucks he had to sample before he found one that knocked!! I'm sure the arbitrator would be VERY interested in hearing his answer to that question.

    How 'bout it, guys; anyone want to load up allchevy with data that GM won't be able to ignore?

    Joe
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    allchevyallchevy Member Posts: 28
    With a little preparation I see how the arbitrator meeting can be a much more sensible experience. It sounds like you have had your share of dealing with the system-Thanks for sharing some of that,its a big help!
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    sonjaabsonjaab Member Posts: 1,057
    Just for a laugh ....take a peek at
    www.tundrasolutions.com
    Seems like a bunch of toy boys are
    having fun with their engines and
    cold start knock !!!!!!!!
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    ndahi12ndahi12 Member Posts: 235
    That should tell you that it is normal is Chevy, Ford and Toyota are having COLD strt-up clatter. It is due to the psiton type that is used. Mine only happens for 1-2 seconds when COLD the first time I start the truck in the morning.

    AFAIK, Chevys have it on every start-up. At least some of the people in this thread have posted that.
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    sonjaabsonjaab Member Posts: 1,057
    From some of the comments made here
    from toy owners....Over the GM knock
    you would have to as confused as I am !
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    buckmaster1buckmaster1 Member Posts: 20
    Lets get real here for most of us 32,000 dollars is a boatload of money for a knocking engine or worse yet a replacement motor that ruins the original integrity of the vehicle.If I pay for it once I want all the right parts and I want all the major driveline parts to all wear out together.NOT my replaced engine has 5,000 miles but my trans and rear have 27,000 miles and I have about 4 years worth of payments left on this piece of junk.You guys who say piston slap will not affect the engines longevity will be the first ones to get the new pistons put in. Truth is-Its not confidence inspiring .Lets put it this way" If the noise went away who would want it back?".
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    knock1knock1 Member Posts: 3
    I was just reading the comments about valve noise and piston slap.I cant believe how many think this is normal for a truck that costs over 30,000.If I understand this correctly the oil sits in the bottom of the pan and the valves get no oil,but there is no valve noise until the truck hits4000 miles or so,I counld only assume it takes about 4000 miles for the oil to get to the bottom of the engine. I think alot of these people who write in on these sites must work for gm,its seems most who say engine noise is no problem isnt having it happen to them. My 30,000 piece of junk was bought back by gm 11-27-01.GM reps told me I couldnt get a buy,they told me my valve clatter and piston slap was normal,they treated me like garbage.They told me the only problem was me,I wasnt use to owning a truck,they also said i didnt have my truck in enough times for a buy back ,only had it in 1 time and the dealer said he couldnt fix it. I had my hearing and it was determined by the BBB that if the noise was only present in 3 or 4 persent of the trucks than it was a defect,and gm had to buy it back. I would also like to add that gm had every chance to fix it.At my hearing I stated that I bought this truck thinking I would get 150,000 or more ,I was then told be gm rep Mary LOU Coates that gm makes their trucks to last 100,000 miles and if any dealer or sales rep said different she wanted to know who. Bottom line is while gm my makes a nice product but theres still no quality behind it and unless your truck stops working they wont fix it.Buy garbage get garbage.
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    ryanbabryanbab Member Posts: 7,240
    "I think alot of these people who write in on these sites must work for gm"

    I wish i could say that
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    ricschricsch Member Posts: 540
    Inquired about the cold-start knock to my pruchasing dealer service person. He faxed me a copy of a bulletin which basically stated that GM feels this is a normal noise and not to worry, that it will not create any issues of excessive wear. It states that the this "common" issue may arise around 12-14K miles, well mine does it at 6000, and was there earlier. I plan on checking with another local dealer to see what they say, and then to call GM and see why some dealers are replacing engines, and telling others that there are new pistons to correct the problem, and yet I'm told it's normal.
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    PAmanPAman Member Posts: 207
    1. It isn't normal.
    2. If it WAS normal, why, then, is GM offering to replace engines, give away free extended warranties, and working on a new piston/ring kit to eliminate the noise?
    3. DO NOT settle for a noisy engine! Insist, IN WRITING, that Chevrolet and General Motors fix your engine to YOUR satisfaction!

    Joe
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    xyz71xyz71 Member Posts: 179
    My truck (99 5.3L) USE TO knock for 2-3 seconds the first start up of the morning. The only way I could hear it was to shut the radio off, snap the seat belt (the gong would cover up the noise), roll down the window and listen really hard. I did not give it much thought until I started reading this board - most likely would never even have noticed it unless I was reading this board. But anyway -

    I took a trip between Christmas and New Years 2,700 miles - about 1,000 of them were at 80 MPH or more. I changed to Mobile 1 a week before the trip, also changed the air filter and wipper blades.

    When I got to Colorado the knock was gone!!

    The first few days I was in Colorado the temp got down to 0 degrees over night. I expected the knock to be worse, but it was gone. I am back in Houston now - and the knock is still gone. I hope it stays away - but my guess is it will be back in a few thousand miles.

    Or maybe the solution to the knock is to change your wipper blades!
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    edetoredetor Member Posts: 12
    My 5.3 had the cold start knock and one of the fixes used by the dealer was to soak the pistons with some type of solvent to reduce the carbon buildup. It worked great for about 1500 miles so i wonder if your extended high speed drive or switch to mobil 1 (or both) had the same effect on your engine. Let us know if the knock returns.
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    nerdnerd Member Posts: 203
    The engine soak will have no long-term effect. They did it to my engine, and the knock returned. Eventually, the knock got so bad that they replaced the engine.
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    nerdnerd Member Posts: 203
    GM replaced the 5.3L engine in my 2000 Sierra due to a loud knock at startup. The dealer argued with GM for a new engine rather than just replace the pistons.

    The new engine is now makes a noise, but not when completely cold nor when first started. The knock occurs shortly after startup and lasts for a few minutes during the warmup cycle. I heard the same sound with the old engine. After some close listening with a stethoscope, I am beginning to think that this noise is coming from an injector since the noise is coming from the same location as the noise in the old engine. (They reused the fuel rail and injectors from the old engine). Just wondering if anyone else has had a similar experience.

    By the way, I found out this week that a used 2000 Sierra is about worthless, at least in Texas. I tried to make a trade for a 2002 F-150, but the trade-in value was so low that I decided to keep my Sierra.
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    modvptnlmodvptnl Member Posts: 1,352
    the chemical soak was for pinging motors, not knocking.

    The theory on the pinging motors was to get rid of build up on the tops of pistons that may have been causing hot spots. I can't imagine how a "soak" could help a knock that's caused by a clearance issue.
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    gator36gator36 Member Posts: 294
    For replacing engines for the knock.
    The engines they are replacing the knocking ones with, have the same pistons as the ones already
    knocking. This then sets the vehicle up for
    a lemon law buyback. GM is aware of the problem
    and from what I understand is working on a fix.

    Who knows
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    rayt2rayt2 Member Posts: 1,208
    But they did document it in writing on my repair ticket, "Customer states experiencing engine lifter tap/engine knock on startup when cold and lasts for 15 to 30 seconds. Tech checked to verify, condition noted, GM is aware of problem and is working on fix" I have not yet pushed for the extended warranty until I approach the end of my 3yr/36,000 warranty.

    Ray T
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    mcrmcr Member Posts: 15
    I have a fairly new 2002 Rado with the 6.0L and a little of 5K miles on it. I have listened and mine sounds smooth with no knocks or pings on startup or afterward. I am on my third oil change using dino oil. About what mileage does the knock show up?
    Thanks
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    western6western6 Member Posts: 11
    Ding! I own a 2001 chevy hd crew cab. Engine knock yep. injection problem at 800 miles, 4X4 switch went out at 4800 miles, new drive shaft at 17000 miles, cab lights leaked at 18200 miles
    dash board rises with defrosters on. Rear springs are sagging ,goes in on tuesday for rear end problems. Junk Junk Junk.
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    rayt2rayt2 Member Posts: 1,208
    If it ain't broke don't fix it would be fair to say with your normal sounding truck. It's hard to say whether you'll develop the "knock" or not. Mine didn't show up for awhile but once it did I always have it. I always get the sound when I start up cold, sometimes even after sitting for awhile when warm it does it too! It always goes away with in 30 seconds or so. I have 26,000 miles so far, check profile for what I have.

    Ray T.
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    edetoredetor Member Posts: 12
    I know the soak was temporary because the knock returned. I also got a new engine in sept 01' and it has been quiet so far with about 5k on it. the service mgr said it came right off the assembly line in sept' so I assume it would have been put in an 02' truck. Was there any hp increase or other changes to 02' engines ?
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    nerdnerd Member Posts: 203
    Our new engines must have come off the line at about the same time. The dealer did not mention any change in HP, and I can't tell any difference. Let's hope we have better luck with the new engines.
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    txyank1txyank1 Member Posts: 1,010
    no changes from 2001 to 2002 in the engines. Or from 2000 to 2001 for that matter.
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    dch0300dch0300 Member Posts: 472
    Here are the changes for the 4.8L and 5.3L engines for the 2001 Model Year.

    - Reduced Main Bearing Tolerances
    - Two-Point Coolant Vapor Vents
    - Revised Intake Manifold
    - Improved Catalytic Converters
    - Improved Mass Air Flow Sensor with Temperature Sensor
    - Extended Oil Change Interval
    - Sleeveless Coolant Sensor
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    obyoneobyone Member Posts: 7,841
    all that mean?
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    dch0300dch0300 Member Posts: 472
    NEW OR CHANGED FOR 2001 MODEL YEAR (4.8L & 5.3L)
    Reduced Main Bearing Tolerances
    Two-Point Coolant Vapor Vents
    Revised Intake Manifold
    Improved Catalytic Converters
    Improved Mass Air Flow Sensor with Temperature Sensor
    Extended Oil Change Interval
    Sleeveless Coolant Sensor

    CUSTOMER BENEFITS

    MORE PRECISE BEARING FIT
    Smaller tolerances in the crankshaft main bearings mean a more precise fit. The result is an increase in long-term durability and, just as importantly, a reduction in something known to engineers as "cold knock"--a slight slapping noise from the engine before it reaches full operating temperature.

    FEWER VENTS
    The number of water pump vapor vents has been reduced from four to two, thereby reducing cost. The vents are located in the cylinder heads, and release gas from localized coolant boiling around the combustion chambers, preventing air pockets that restrict coolant flow. Experience with has shown that two vents are sufficient.

    REVISED INTAKE MANIFOLD
    The intake manifold has an improved purge isolator--the rubber device used to mount the solenoid that manages fuel injection-to reduce noise and vibration. The new manifold also has a new, more durable injector director plate, with two large holes rather than four smaller one to reduce potential for clogging.

    BETTER CATS
    Both the 4800 and 5300 have 74-ci primary converters that are manufactured with less precious
    metal, at considerably lower cost. A new catalytic coating and thin-wall catalyst substrate--the source of the catalytic reaction that turns exhaust emissions to harmless vapor--allow improved performance with less platinum, palladium and other precious metals in the converter.

    For 2001, the 4800 and 5300 are National Low Emissions Vehicle (NLEV) certified. Vortec 5300s built for California Suburbans are fitted with a pair of "pipe converters," or an extra pair of small catalytic converters in the takedown pipes from the exhaust manifold. As a result, the 5300 is Ultra Low Emissions Vehicle (ULEV) certified for California--the current most stringent emissions standard.

    BETTER MAF
    A new Mass AirFlow (MAF) sensor features an integral inlet air temperature sensor, which allows the Powertrain Control Module to adjust for optimal performance at a given air temperature. The result is more efficient combustion and fewer emissions in all operating conditions.

    LONGER OIL CHANGE INTERVAL
    New computer algorithms extend the maximum oil change interval from 7,500 to 10,000 miles. The Powertrain Control Module records engine temperature and length of operation at a given temperature, then indicates an oil change when it's actually needed, rather than according to a predetermined interval. With new data on real-world customer use, Powertrain engineers have adjusted the software to allow the longer maximum oil-change interval.

    COOLANT SENSOR
    The new coolant temperature sensor uses a plastic insulator to protect electrical leads inside the brass housing, rather than a rubber sleeve, and reduces the possibility of assembly rejection or shorting in operation.
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    whatsachevywhatsachevy Member Posts: 136
    '01 Chevy 2500HD 4x4 Ext Cab SB 6.0/4.10 Auto Locker - 12,000 miles and only a slight engine knock on cold start-up. Other than that, no problems. I have to admit, so far this truck is awesome (and no, I don't work for GM - I'm actually an old Ford guy - this is my first Chevy product, ever). I did take the truck in to my dealer to register the engine knock. I was told the same story as most that engine longevity would not be compromised. I did note the engine knock concerns on the service follow-up questionnaire that I mailed back to GM in December. I received a phone call last night from GM rep. They asked about my concerns and called me back tonight. They gave me a no-cost 5-year/100,000 mile extended warranty on the engine and all internal engine components. They agreed to replace the pistons when the newly designed ones are available at no cost allowing the extended warranty to continue in effect. Maybe some people should look for another dealer or call GM customer service directly (1-800-222-1020). Personally, I don't think the longevity of the engine is compromised, and was quite pleased that GM took the time to call me and apparently stand behind their product. I have a buddy who has a '97 GMC 1/2-ton that has been through hell and back several times (it has even been buried in a pond with water up to the bottom of the dash). His truck has also had the cold-engine start-up knock since about 5,000 miles. He now has over 90,000 miles with no oil consumption (but he does still have the same knock - it has not gotten worse over time). 90,000 miles on a truck for him should be worth at least 180,000 for a normal person as we consider him to be "above-average hard" on vehicles.
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    PAmanPAman Member Posts: 207
    Some of you have described a slight knock, more like a ticking sound, at cold start-up. The colder the climate, the more likely it will occur. That is lifter noise, has been around for years in virtually ANY internal combustion engine with hydraulic lifters, and unless it doesn't go away in 5-30 seconds, is completely normal. It is also more likely on high-mileage engines because of the sludge build-up in small areas like valve lifters and narrow oil passages.

    It is caused when the hydraulic lifters don't have enough oil in them at start-up, and continues until the oil volume in the top of the engine builds up. This is often caused by using a too-light weight of oil such as 0W20, 0W30 or 5W30, or by using a straight-weight oil, such as 30W or 40W. The too-light oil flows down into the crankcase too easily; the straight-weight oil is too thick at start-up, and it takes longer for the oil pump to get it moving.

    If you are concerned about it, you can use some engine flush just before your next oil change, and step up the weight of your oil one grade, or go back to using a multi-grade. Virtually all modern engines are designed to use multi-weight oil anyway, but there are some out there that started on 30W fifty years ago, and will never change.

    The knock that many users in this forum are trying to have addressed is a knock that occurs once the engine is warm. It is likely caused by excessive spacing in the ring grooves on the pistons, allowing the rings to make a rattling sound when the piston changes direction.

    The fact that some engines do it and some don't suggests that either GM or its suppliers allowed too wide of an acceptable range in the size of the rings or the pistons, or both, or the engine was designed with rings and pistons the wrong size. For example, if the rings in your engine are a few thousandths of an inch larger than the ideal size, and the grooves in the piston are slightly narrower than the engineer intended, your engine probably doesn't knock. However, if you go to the opposite extreme--narrow rings in a piston with wider than normal grooves--you get the knock.

    While the jury is still out on whether it affects engine durability, it is annoying at best, and a sign of sloppy quality control at worst. Some have even suggested that GM knew some engines would knock, but thought they could pass the noise off as normal. Guess they under estimated the devotion owners of nearly all brands of trucks have for their personal vehicles.

    While I don't have one of the affected engines, I hope those of you that do keep the fire under GM's butt to cover the engines that are on the street, and design a fix for future engines. One thing you can take to the bank--the ONLY way GM will care about this problem is if it costs them enough money--either by paying to fix existing engines, or potentially loosing sales of new trucks. When the bean counters take notice, it is amazing how quickly things get done!

    As for the owners of other brands that love to troll through here making immature remarks about GM trucks--so what? EVERY manufacturer has let vehicles go out the door that were not perfect. Yes, EVERY single one of them!

    Joe
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    ricschricsch Member Posts: 540
    If I were to use 10W30 instead of 5W30, in your opinion, would I notice less knocking or the ticking noise on start up?
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    PAmanPAman Member Posts: 207
    He claimed that he got rid of the noise by going from 10W30 to 20W50. Please remember that this is for use in San Antonio--a city with a semi-arid climate located on the edge of a desert. Using 20W50 in the winter in many areas of the country may not be a good idea.

    I don't know why bamatundra would say that 5W30 and 10W30 oils are the same. There are specific and measurable differences between 10W30 and 5W30 oils, whether they are synthetic or non-synthetic. Please keep in mind that the standards for oil are set by the SAE, the Society of Automotive Engineers, and NOT by the oil's manufacturer. If Mobil were selling the same oil as two different weights, it would seem that they are setting themselves up for a ton of lawsuits, both from individual users and various state attorneys general offices for consumer fraud.

    For more information about oil standards, go to their web site at www.sae.org

    Joe
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    ryanbabryanbab Member Posts: 7,240
    "In the case of Mobil 1, you would not see a difference. 5W-30 and 10W-30 are the exact same oil packaged differently. "

    More misinformation
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    ndahi12ndahi12 Member Posts: 235
    "In the case of Mobil 1, you would not see a difference. 5W-30 and 10W-30 are the exact same oil packaged differently."

    First the pictures and now this!!!!
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    bamatundrabamatundra Member Posts: 1,583
    From: "http://www.off-road.com/RoverWeb/OilFAQ.html"


    Oil...........................VI......Flash......Pour

    Mobil 1 10W-30........160......450.......-65

    Mobil 1 5W-30..........165......445.......-65


    Sure look like the same oil to me! Although the Viscosity Index is slightly higher, this number is only comparable within the same viscosity class of oils. An oil with a smaller viscosity range would be expected to have a higher viscosity index. The Flash Point and Pour are nearly identical as would be expected with the SAME oil.

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    edraweedrawe Member Posts: 2
    I wish someone with the connections or know how would get a class action suit going over this and I bet we would get some action.
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    ryanbabryanbab Member Posts: 7,240
    "nearly identical "

    is not the same as

    "exact same "

    Ryan
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    edraweedrawe Member Posts: 2
    I wish someone with the connections or know how would get a class action suit going over this and I bet we would get some action.
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    PAmanPAman Member Posts: 207
    Here's data extrapolated from the Mobil 1 web site:


    Mobil 1 Tri-Synthetic 0W-30 5W-30 10W-30 15W-50

    Product Number 48116-8 48111-9 48117-6 48120-0

    API Service Classification

    Gravity, API 33.0 32.8 32.0 30.2

    Specific Gravity 0.860 0.862 0.866 0.875

    Pour Point,°F -65 -65 -65 -55

    Flash Point,ASTM D 92,°F

    460 455 470 473

    Flash Point, ASTM D 93,°F

    412 410 430 433

    Viscosity Index 176 162 147 160


    This is not all of the data they have posted; if you want to see their entire spread sheet, go to this link, then click on the product data sheet:


    http://www.mobil1.com/index.jsp


    Like I said before, there are distinctive, measurable differences in the two different weights of oil. Even if you only look at the data that bamatundra quoted, there are still notable differences in Viscosity Index (VI) and flash points.


    Joe

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    ndahi12ndahi12 Member Posts: 235
    Now you did it!!! Bama will start posting picture to prove his point. You cannot debate bama he is always right :-P
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    quadrunner500quadrunner500 Member Posts: 2,721
    Please refrain from posting disinformation here. For 5W-30 the base stock is 5 weight. 10W-30, the base stock is 10 weight. Not the second number.
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    quadrunner500quadrunner500 Member Posts: 2,721
    ROFLMAO!
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    quadrunner500quadrunner500 Member Posts: 2,721
    Bama to PAman:
    >You have shown very good proof that Mobil 1 5W-30 is actually different oil than 10W-30. Someone posted on another website that they were the same and when I checked the properties on yet another website they appeared identical. I should have checked at Mobil 1 website as you did.<

    You just admitted the information you posted earlier from someone on another website was erroneous. Now you cite the same misinformation as PROOF! ROFLMAO!!!!!!!!!!!!!
This discussion has been closed.