winter oil weight

Discussion in 'Diesel Additives, Oils, Lubricants, Fuel, etc.' started by BigBadCummins, Dec 21, 2003.

  1. BigBadCummins

    BigBadCummins Registered User

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    Hi fellas,
    I have a 90' Dodge with a Cummins and I do not always have access to a source of power to plug my truck in when it gets cold out. I am concerned about the length of time it takes to build oil pressure when it's not pluged in which is sometimes up to 10-15 seconds. I am running 15w-40 Rotella right now and would like to know if I can stay at the same weight and go to synthetic or can I go to a thinner weight oil and not change to synthetic after all of these years. I personally like the man made stuff but I am concerned about developing oil leaks if I switched.

    Thanks for the advice.
    Kurt.
     
  2. Hippie

    Hippie Registered User

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    I've started my '98 12V at -15 without it being plugged in. Amsoil definitely helps starting.

    Also, the Amsoil remains more 'liquid' at very low temps. Whatever oil you use, keep using the 15W40 weight, *unless* you are somewhere where the temps stay under -10 for long periods of time. If you do see such temps for prolonged periods of time, you can switch to a 5W40. The engine wants a 40 weight oil, so that's what you should use.

    Hippie
     
  3. BigBadCummins

    BigBadCummins Registered User

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    Hippie,

    Thanks for the help, I was kind of leaning towards Amsoil and it looks like that is the way I am going to go. I have used it in my sleds for a few years with no problems and don't see any reason it will not work as well in my truck.

    Kurt.
     
  4. ISurvivedNMU

    ISurvivedNMU Full Access Member

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    Hippie,

    Why not switch to synthetic (5w40) in the winter even if your temps are higher than 10 degrees? for cost, or do you not benifit......

    Thanks:thanks:
     
  5. Hippie

    Hippie Registered User

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    I couldn't recommend it because I don't know how 5W40's viscosity behaves in the intermediate temps. That is, if your engine requires 15W40, that oil has been selected to provide ... a specific voscosity across the 'normal' temp range. Consider: at full operating temp, 15W40 part of the oil has a certain viscosity. When the engine is cold, the oil's viscosity should be about the same. Worded differently, 15W40 is intended to have a reasonably consistent viscosity from, say, 10F to 250F.

    On the other hand, 5W40 is going to be a thinner oil when cold. The questions are "How much thinner?" and "At what temps?" If it is shown to have the same viscosity as 15W40 in 15W40's optimum temperature range, as well as maintaining that viscosity down to a significantly lower temperature, then I would say there is no reason not to use it. If, however, it is significantly thinner (or thicker) than 15W40 in the lower end of 15W40's optimum temp range, I would be hesitant to use it, because it is thinner (or thicker) than the recommended oil. Oil that is too thin or too thick does not provide proper lubrication.

    In the above commentary, I use 'viscosity' to refer to oil's general lubricating qualities. A proper oil dissertation would discuss viscosity along with all of oil's other lubricating properties, such as the additive package. In the interest of simplicity, I grouped everything under the term 'viscosity'.

    Hippie
     
  6. BigBadCummins

    BigBadCummins Registered User

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    Last year when I was a ATV/Bike/PWC/Snowmobile mechanic we had a Honda ATV come into the shop that would overheat when it was used for plowing snow, everything checked out good, oil cooler, cooling fan, proper oil level, and fins on engine were very clean. We changed the oil and filter and installed the proper oil ( Honda GN4 - 10-w40) The machine was brand new and again eveything test good for the cooling system but it would always overheat, none of us at the shop could figure out the cause. We finally called the Honda service Rep and he said to try a thinner oil and it should cure the problem. He stated that the thinner oil disipates heat quicker and would still give proper lubrication.
    Well we called the customer and told him what the Rep had said and asked him if that is what he wanted to do. he said to go ahead so we put 5-W30 in the engine and ran it while plowing some snow and the temp light never came back on. The customer picked up his quad and as far as I know he never had the problem return.

    That was the only time I ever had seen a overheat issue like that and was a little leary about not going by the book as far as the recomended oil, it seemed to work in that case.

    Just my .02.
    Kurt.
     
  7. Big K

    Big K Guest

    I've used the 15-40 HDDM for over 15 years. I'm sold. Amsoil does make a 5w-30 Diesel oil, but I just have a hard time convincing myself that a lighter weight oil will be as effective as the HDDM. Personal problem, I guess. :rolleyes:

    Leaks developing after the switch are a possibility. These are great engines, however, and the incidence of such seems to be significantly less than that of say, a gasser with 100k.
     
  8. Big K

    Big K Guest

    TTT for new members
     
  9. JimmyDee

    JimmyDee Full Access Member

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    Synthetics have stood the test of time and your fears about the thinness and effectiveness of the lighter weight synthetic oils are totally unfounded. Even though it has not been proven that they make an engine last longer, it sure don't hurt them. I use 5 w 40, Delvac 1 every winter with no problems of any kind. How long do you think a major trucking company would use a synthetic at 3 times the price, if they weren't getting what they want from the oil?
    Jim
     
  10. camoman

    camoman Registered User

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    Well I just switched to Amsoil 5w30 with there new EA filter. Going to run it the rest of the winter and into the summer to see how it goes...
     
  11. Mr_Roboto

    Mr_Roboto Full Access Member

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    Thinner oil does not lubricate less, as long as adequate oil pressure is maintained. Look at the new cars that use 5w20 or 0w20 oils.

    I'd be a lot more concerned about the lack of oil flow at startup than the oil thinning out at temperature.

    The only reason thicker oil works "better" in older engines is because it leaks out of the bearings slower, helping to keep oil pressure up. This is compensating for excessive wear in bearings, it doesn't make the thicker oil "better" in all situations.

    I've had pieces of crap that I ran straight 50 weight oil in, and they would still lose pressure at hot idle. Run em till they blow!
     
  12. tonkadoctor

    tonkadoctor Full Access Member

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    I've run Rotella 15w- 40 for years and always felt it performed well. Made a switch to Rotella T 5w-40 synthetic in the Powerstroke and it makes a big difference in how well it starts. Oil pressure comes up alot faster hot or cold and the engine runs quieter.

    Rotella Synthetic is about $16 or $17 gallon at Walmart. Handed them the Oil and Filter at the car care center and my oil change ended up being $99 for the synthetic change at wally world vs $79 at the Ferd dealer. IMHO it was worth the $20 difference in price;Sweet

    Walmart Synthetic oil change price break down.
    1. $68 for 4 gallons Rotella T Synthetic
    2. $14 for the Fram Extraguard Oil Filter
    3. $17 for Labor (16.39 actually)
    I now have 1000 miles on this oil and it still looks like it was just poured from the jug, clean & clear.....Bear in mind that this in an engine with 328,000 miles and there is about 2 quarts of old oil you usually don't get out of the High pressure oil system on the Powerstroke. I'm very pleased.
     
  13. that stinky ford

    that stinky ford Registered User

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    It might just be me... but I like seeing my oil dirty. It tells me that the oil is absorbing some of the grime and sh!t that our engines make. I'm not calling you out, but I find it hard to believe that you have 1000 miles on your oil change, and it is still clear. You do an oil change in a diesel, fire it up, kill it, and the oil is pretty much black again.
     

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