Author & Automotive Expert James D. Halderman
|Halderman newsletter||November 2017|
As I was working on a revision of an electrical chapter, I asked my artist, Carl Borsani, to help me create figures showing the three levels of dash warning systems. After a couple of weeks and many versions, we ended up with 128 dash symbols broken up into three areas by color:
- Green (Blue)- Used to inform the driver what is in operation
- Amber- Used to inform, the driver of a detected concern
- Red - Used to warn the driver of a fault requiring immediate attention
This chart has now been posted on the homepage of my website where it can be easily downloaded and printed so that it can be used in every school and shop in the country. Visit www.jameshalderman.com. | |
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|Puzzle of the month|
Find this month's puzzle of the month at this link
and test your students knowledge on engine performance (A8).
Which manufacturer designed the engine for the Bugatti Veyron?
Answer at the bottom of this page!
How can a cracked exhaust manifold affect engine performance?
Cracks in an exhaust manifold will not only allow exhaust gases to escape and cause noise, but also allow air to enter the exhaust manifold. Exhaust flows from the cylinders as individual puffs or pressure pulses. Behind each of these pressure pulses, a low pressure (below atmospheric pressure) is created. Outside air at atmospheric pressure is then drawn into the exhaust manifold through the crack. This outside air contains 21% oxygen and is measured by the oxygen sensor (O2S). The air passing the O2S signals the engine computer that the engine is operating too lean (excess oxygen) and the computer, not knowing that the lean indicator is false, adds additional fuel to the engine. The result is that the engine will be operating richer (more fuel than normal) and spark plugs could become fouled by fuel, causing poor engine operation.
|Sample ASE certification-type question|
An increase in oil viscosity can be due to ___________.
a. Wear metals in the oil
b. Fuel dilution of the oil
c. A clogged air filter
d. All of the above
The correct answer is a. Small particles of steel, cast iron, and other metals in an engine can react chemically to increase the viscosity (thickness) of the oil. Answer b is not correct because if fuel were added to oil, it would become thinner (lower viscosity). Answer c is not correct because a clogged air filter does not have a direct effect on the viscosity of the oil. It is true that dirt could get into the oil, which will make the oil thicker but this is not a direct result of the air filter itself. Answer d is not correct because it includes b and c, which are not correct.
1. Never reuse an old gasket. A used gasket or seal has already been compressed, has lost some
of its resilience, and has taken a set. If a used gasket does reseal, it will not seal as well as a new gasket or seal.
2. A gasket should be checked to make sure it is the correct gasket. Also check the list on the
outside of the gasket set to make sure that the set has all the gaskets that may be needed before
the package is opened.
3. Read the instruction sheet. An instruction sheet is included with most gaskets. It includes a review of the things the technician should do to prepare and install the gaskets, to give the best chance of a good seal. The instruction sheet also includes special tips on how to seal spots that are difficult to seal or that require special care to seal on a particular engine.
From the October 28, Wheels section of Dayton Daily News
Reader is confused about oil level
Randall writes by email:
"I have a 2008 Dodge minivan with a 3.8 L engine. When I check the oil with the dipstick, I get a different reading every time, no matter how many times I check it. I called the dealer, he said to start the car and run the engine for a couple minutes. Then, shut it off and let sit a couple minutes, and check the oil level. It's still the same. Do you have a suggestion?" Halderman
: For most engines, the oil level should be checked before starting the engine and after it has been sitting overnight. I have read that some engines will not display an accurate oil level unless the engine has been off for an hour or longer. It takes a long time for the oil to travel from passages and locations, such as the cylinder head and overhead camshafts, and back into the oil pan. Also be sure that the vehicle is on a level location to avoid an error in reading the oil level. Therefore, for best results, park somewhere level and check the oil in the morning before starting the engine. Remove the dipstick and using a shop cloth, wipe the oil off and reinstall. Be sure that the dipstick is fully depressed to get an accurate measurement. Remove the dipstick a second time and observe the oil level. The oil level should be between full and add. Do not overfill. The add mark indicates that 1 quart of oil is needed.
|Trivia question answer: B. |
Please let me know what you think of the newsletter. I would love to include any of your automotive news, trivia questions or any tech tips you might have. Send me your suggestions!
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James D. Halderman writes automotive technology textbooks for Pearson Education. He is an ASE-certified Master Technician with more than 20 years instructional experience.