Quote:
|
Originally Posted by mike c
You don't change the oil because it is "breaking down", you change the oil because you want to remove the contaminents that get into it. Oil can last a long time, 10-20K miles, but that's like saying you can go two weeks without food. yeah it will work, but is it healthy? Change your oil every 3,000 miles and you will be good, even every 5,000 is probably fine, but for the price of it, why not be better safe than sorry? Like someone said earlier, if it is all black and smells of chemicals and metal, it's good that you are changing it.
Synthetic. Why is everyone so hell bent on using it? What is it doing that is so great? If you change your oil every 3K miles anyways, you are wasting your money.
And to all the people out there that "trust" the engeneers for Honda, that's great, I just hope you don't have that same mindset for the Honda "techs" that you trust to change your oil. A lot of times they are just normal people that know how to turn a wrench, and that does not take a lot of skill. Trust me, they aren't ALL that great(and there are some real good ones). On my dad's Honda that he bought from a dealership, to fix a cross threaded oil plug that they screwed up, they just put some caulk or something like that in there so it wouldn't leak. How's that for brains?
Mike C
|
Humm... yeah oil does break down. Trust me, you can not go on the same oil for 10k miles without adding oil and additives. Truckers do it, but they add oil every few thousand miles because some gets burned as "blow by" and some gets just burned off. The key to having oil last that long is making sure the oil is synthetic.
First you have to understand that oils viscosity is do to the size of the carbon chain present. Dino oil uses a range of sizes to make sure the AVERAGE size is the correct size for the viscosity that you want. The problem with this is that smaller molecules burn easier than larger ones, hence the small oil will burn off leaving only the larger molecules. This will make the viscosity go up, or make the oil thicker, making for less protection over time. Synthetic oils molecules are all one size, so they all have an equal chance of getting burned off. And when they do, the average size does not change, so viscosity does not change. This is why synthetic oils can last longer than dino oils. This is why dino oil generally last a little over 4,000 miles and synthetics 5,000-10,000 miles depending on what you add and what oil it is.
The reason you change your oil (you are partially correct) is because of additives. The 3,000 mile oil change comes from a time when no additives where used, creating carbon build up and sludge. Today, oil additive made by companies like Lubrizol allow the oil to keep this carbon and other harmful contaminant in suspension so that it does not deposit in the engine. However, these additives burn off (just like the oil) and the oil over time will loose its ability to suspend the contaminates and result in depositing them in the engine, this is bad. Hence the reason you change your oil. You can (like truckers) replace these additive and add oil for the oil that has burned off, but generally people don't drive their car that much and the time factor (aka oxidation) ends up killing your oil.
Why does oil and additive burn off? Just like anything else, if you add stress to it, it breaks down. When you run your engine, you are putting thermal stress on your oil and sheering stress. Thermal stress comes from the oil cooling the bottom of you engine, like antifreeze cools the heads, oil cools the crank and pistons. Sheering stress is when two molecules try to move past each other, think of a crowded hall way. Now say you are traveling at 100 MPH and hit some else going the opposite direction in the shoulder, you break you shoulder off probably, same idea with sheering stress and oil.
And yes, I don't trust Honda's techs considering what they have done to me in the past.
