Author & Automotive Expert James D. Halderman



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Halderman newsletterSeptember 2017
What's new with Jim? 

Welcome to this month's newsletter and I hope everyone had a great summer. My webmaster, Carl Borsani, has been busy all summer getting all of the resources posted on my website so that it can be used to help teach classes in the fall semester. The following updates have been added during the summer:

1.     The home page at   has been updated so it is easier to navigate and find what is needed.

2.     New content on oil change requirements for all vehicles specifications has been added to the website.

3.     Lug nut tightening torque specifications for all vehicles are posted on my website under "service information."

4.     Tire pressure monitor sensor relearn procedures are posted on my site for all vehicles from 2007-2015.

5.     All video links (over 2,000) have been checked to make sure there are no broken links. If a link was found to be broken, a replacement video link was found to replace it.

6.     There are now videos for each NATEF task on my website and they are FREE.

7.     The 2017 NATEF task list correlation charts for all titles have added and are posted on my website to make it easy for instructors to meet the latest NATEF standards.

Enjoy using my site and please use these free resources to make teaching and learning easier for you and your students.

Find Jim online
Puzzle of the month
Auto Trivia
At car shows, some older engines that used a cylindrical ignition coil are mounted upside down, with the secondary coil wire exiting at the bottom of the coil. Why?


a.     To prevent moisture from getting into the coil

b.     To keep the oil in the coil at the output (secondary) terminal to help insulate it from the primary windings.

c.     To improve engine performance

d.     To provide a shorter distance for the spark to flow to the center of the distributor cap

Answer at the bottom of this page!
Why is most coolant 50/50 with water?

According to the freezing point, it appears that the lowest freezing point of coolant is achieved when 70% antifreeze is used with 30% water. While the freezing temperature is lower, the high concentrate of antifreeze reduces the heat transferability of the coolant. Therefore, most vehicle manufacturers specify a 50/50 mixture of antifreeze and water to achieve the best balance between freeze protection and heat conductivity.

Sample ASE certification-type question
A compressor is being replaced. Technician A says that the oil should be drained from the old compressor and measured so that the same amount of oil can be installed in the replacement compressor unless it is shipped with oil. Technician B says the drained oil should be installed in the new compressor to make sure that it is lubricated with the correct oil. Which technician is correct?
a. A only
b. B only
c. Both A and B
d. Neither A nor B
The correct answer is a. Technician A is correct because the compressor must have enough, but not too much, lubricating oil in the system. Because the compressor holds most of the oil in the system, it is important that the quantity be accurately measured so the correct amount can be installed in the system with the replacement compressor. Technician B is not correct because old refrigerant oil should not be reused. Most refrigerant oil is hydroscopic and absorbs moisture from the air, thereby becoming contaminated. Answers c and d are not correct because Technician A only is correct.

Tech Tip
The Paper Test
To determine if there is adequate airflow through a condenser, many technicians place a sheet of paper or a dollar bill in front of the condenser when the cooling fans are operating. With the engine running and the A/C commanded on and working, the bill should stick to the condenser.

Straight Talk
From the August 26, Wheels section of Dayton Daily News
Does synthetic oil buy me time?

Jim of Centerville asks:
"I own a 2014 Chevrolet Impala and I was wondering if I used synthetic engine oil, can I delay the oil change interval? My car shows the life of the oil in percent and often shows a message to "change oil soon" after just six months of driving. I would rather delay the need to change the oil to once a year so I don't have to visit a shop as often".
The short answer is no. Your GM vehicle requires the use of Dexos certified engine oil and this specification, which is available from many different oil brands, is formulated to meet the needs of your engine. According to General Motors, the oil life monitor (OLM) should be used as your guide to change the oil regardless of the type of oil used. When the OLM is reset after the oil has been changed, the Powertrain Control Module (PCM) monitors the operation of the engine and the number of starts and subtracts a percentage from 100 as determined by the level of harm that the oil may experience. For example, a cold start when the temperature is below freezing may cause the PCM to subtract 1 number, whereas it may require a long trip at highway speed to subtract the same one point. In other words, the time and miles it takes for the PCM to count down to about 15% and show the message to "change the oil soon" varies as to how the vehicle is driven. Short trips and city driving will cause the oil to be changed more often compared to those who drive many miles at highway speed over long distances.   
The bottom line is to use the specified engine oil and change the oil when the oil life monitor indicates that it is time to change the oil. 

Have an automotive question? Please write to Jim with your questions at
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! 
You can email me here or visit my website. You can connect with me on Facebook, Twitter and LinkedIn too (links above). 
Jim Halderman
James D. Halderman writes automotive technology textbooks for Pearson Education. He is an ASE-certified Master Technician with more than 20 years instructional experience.