Eliot Silverman

Eliot Silverman

Thursday, March 29, 2012

If I use regular oil (non synthetic) how often should I change my engine oil?

Until recently manufacturers and independent repair shops said you should change your oil and filter every 3,000 miles or 3 months whichever comes first.  Recently, manufacturers have stated that the oil should be changed every 7500 miles under “Normal” conditions.

This “Normal” condition statement, in my mind, is a winnie clause.  I say this because of how manufacturers define ‘Normal.”  “Normal Conditions:” engine at operating temperature (What does that mean?) at highway speeds, and in a dust free environment. 

“Severe” condition is defined as: stop and go driving, trips of less than 10 miles, city driving, or extreme heat or cold.

Think about those two conditions…. Where in the USA will you be able to drive in “Normal Conditions?”  I can’t think of any, and for sure NOT in Chicago.

If you drive your car almost anywhere in the USA you will be driving in “Severe” conditions.  Therefore, you should change your oil and filter every 3,000 miles.

In Chicago I recommend you change your oil every 3,000 miles or 3 months. 

Because dirt in your oil can cause severe wear, you are safer changing the oil and filter
too often rather than not often enough.
Your oil is your engine’s cesspool system.  The oil filter stores a limited amount of dirt.  Once you exceed the limit, the oil and dirt bypasses the filter allowing the dirt to cycle throughout your engine.  Nobody knows how much dirt is in the oil, and how quickly it accumulates.  When you get an oil, lube, filter change, mechanics do not inspect the oil filter- we don’t have the equipment to do so, nor would you want to pay for that inspection.  Therefore, we do not know if you really need a filter, or if you waited too long before it was changed.  To prevent severe wear and tear in your engine, you are much better off changing the filter too often rather than not often enough.

Every once in a while I get a car whose oil is rarely changed.  In these cases, the oil has solidified inside the engine.  There are small passageways the oil needs to flow through to properly lubricate your engine.  When the oil solidifies it will not flow through these passageways causing premature engine failure.

Some newer models have a “variable cam shaft.”  Using a variable cam, engineers have been able to increase horse power without increasing the size of your engine.  Oil is used to ‘vary the camshaft.’  If you don’t change your oil often enough, or you use the wrong viscosity oil, the passageways to the variable camshaft ‘plug’ and the shaft doesn’t “Vary.”  This causes the ‘Engine’ light to come on. 

Changing the oil does NOT unplug the passageways.  The only way I know to unplug them is to put a thin metal rod, like a pipe cleaner, through these passageways. Sounds easy, but it is very expensive, and sometimes not even possible.

If you use the proper viscosity oil, and change it on a regular basis, you prevent clogging, and premature engine failure.

Friday, March 23, 2012

Your Engine Oil

There are two basic types of engine oils-Regular and synthetic.  Synthetic oil can be used in all cars, but regular oil cannot be used in cars which require synthetic oil. 
There are two other factors which differentiate oil:
Viscosity:  viscosity is a measure of the oil’s ability to flow.  As the temperature drops, oil tends to thicken like molasses, and as the temperature rises, oil tends to thin-out like water.  You need oil to flow through your engine when it is zero degrees outside and when it is 100 degrees outside. 
Oil manufacturers added chemicals to their oil so the oil maintains a consistent viscosity through a wide range of temperatures.  Oil companies label their oils, such as 5W30 or 05W20 so you/me know the viscosity.  The automobile manufacturers require specific viscosity oils for their cars. 
The lower number refers to the ability of the oil to properly flow at low temperatures, and the high number represents the ability of the oil to properly flow at high temperatures.  It would have been nice if those numbers represented degrees Celsius or degrees Fahrenheit, but they do not.  In Chicago a “5” as the lower number is adequate all winter long.  In areas where the temperature gets well below zero, Valvoline makes a ‘0’ weight oil.  In Chicago a ‘30’ weight oil is adequate for our summers. 
For reasons not known to me, there are some cars which require 5W20 oils.  Even though the upper number is ’20,’ these oils are fine for Chicago summers.  The proper viscosity oil for car is always in the owner’s manual, and often found on the oil fill cap.  Most of the time, but not always, if your car needs synthetic oil it will say so under the hood.
The last of the equation is the version of the oil.  Oil companies have made tremendous advances in their oil.  When there is a change it is indicated by the letter following the viscosity range.  I don’t know the current letter.  I don’t need to know since I buy Valvoline oil and they always bring me the latest version.  The latest version can always be used in older cars, but you should not use older versions in newer cars.  If you buy oil from any respectable retailer you will be getting the latest and greatest version.  I point this out in the event a friend of yours offers you the oil which has been sitting on the shelf of his garage for the last 10 years.  This ten year old oil, may not be the best for your car.    
Other notes on oil:
The oil manufacturers add other chemicals to their oils.  They add a chemical which isolates water.  Without this additive the water would tend to cause rust inside your engine.  They add an anti-foaming agent.  Without this additive the oil would foam-up inside you engine.  This might sound cool, but your oil pump cannot pump foam, it can only pump a liquid.  And you would not be able to drive very long without being pumped insides your engine.  They have also added friction modifiers to increase gas mileage. 
Next week I will share with you why I recommend you change your ‘regular’ oil every 3,000 miles – and why the manufacturers might say something different, but add a weenie clause to their initial recommendation.

Thursday, March 15, 2012

All About Your Car's Different Oils

Your car has many different oils; engine oil, transmission oil, power steering oil etc.  These oils are different.  While many people think auto manufacturers are dumb, which they might be, they are not stupid.  They would not stock different oils if two or more were the same.  The oils are different because they do different jobs, and they are exposed to different environments.  For example, engine oil is exposed to the high temperatures from the engine, while power steering fluid is not exposed to those conditions, so it doesn’t get nearly as hot as engine oil. 

Years ago I was told you could use transmission oil instead of power steering fluid.  If you were stuck on the side of the road, and you needed power steering fluid, you could use transmission fluid to continue your trip, but you’ll need to flush the power steering system as soon as possible.  If you were to run your power steering fluid with transmission oil, you would ruin the power steering components. 

There are many different types of transmission oils.  If you had to, you could use the wrong type of oil to get to the nearest auto repair shop.  Once there, you’ll need to flush the transmission, and then add the proper transmission oil.

Years ago I had a Honda which wouldn’t properly shift gears.  My transmission rebuilder said that was a common problem if the wrong transmission fluid was used.  He said he has fixed many Hondas which had this problem by just using the proper oil. 

There are many different viscosity oils on the market.  In a pinch you could add the wrong viscosity oil, but once again, as soon as possible you should do an oil change.   If you car uses synthetic oil, you should never used regular oil, but if your car uses regular oil you will not do any harm using synthetic oil.  More on this later. 

Of all the oils, the brake fluid is the one which deserves the most respect.  You cannot add anything but brake fluid to the brake fluid system.  NONE!  If you add the wrong fluid to the brake system you can ruin all the rubber seals in the brake system.  That means you will need to replace the brake calipers, master cylinder and the ABS system.  This will cost you over $1000.00.  It is so important I’m going to repeat myself.  Never, EVER, under any circumstances add anything but brake fluid to the brake system.

More on these oils next week.

Tuesday, March 13, 2012

How Does My Engine Work?

A car’s engine is a mechanical marvel.  Every time we have to replace a head gasket I get to see some of the insides or an engine, and I’m always impressed.  The type of engine you have in your car was developed over 100 years ago.  The basic principles apply which applied then, apply to today.    However, the application of these principles has significantly increased for the better.  Better gas mileage, more power, and less polluting.

An engine converts heat energy, created from burning air and gasoline, into mechanical energy (used to move your car). The car has a piston which moves up and down in the engine, and valves which open and close.  It is a well choreographed machine which produces a lot of power.  A piston goes up and down four times in order to produce one stroke of power.  I could start the explanation anywhere along the path of the piston.  I decided to start with the intake stroke. 

Intake Stroke:  This stroke starts with the piston at the top of its stroke.  The intake valve opens as the piston starts to move from the top of its stroke to the bottom of its stroke.  As the piston moves downward, it pulls in air and fuel.  At the bottom of the stroke the intake valve closes.

Compression Stroke: With both valves closed, the piston moves up the cylinder compressing the air and fuel.  Most cars have an 8 to 1 compression ratio.  That means at the top of the stroke the air-fuel mixture is one-eight its original size.  On a side note, as the piston compresses the air and fuel the temperature of the mixture increases.

Power Stroke:  At the top of the compression stroke, with both valves closed, an electrical spark jumps the spark plug gap igniting the air and fuel.  As the mixture burns, pressure builds up inside the cylinder.  This pressure, which pushes the piston downward, creates the power to move your car.  This is where heat energy is converted into mechanical energy.

Exhaust Stroke:  When the piston is at the bottom of the cylinder the exhaust valve opens.  As the piston moves up the cylinder it pushed the hot exhaust gases out of the engine.  When the piston is at the top of its stroke, the exhaust valve closes and the intake valve opens.  And the cycle starts again.

This is called a “4 Stroke” engine because it takes 4 strokes to produce one power stroke.  A 4 cylinder engine produces one power stroke per one complete revolution.  While one piston is in the “Power Stroke” the other four engines are in one of the other three strokes.  With an 8 cylinder engine, two cylinders produce power with each complete revolution.  This is why, everything else being equal, the more cylinders you have the more powerful the engine.