RockAuto May Newsletter : Early Edition
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Another Happy Customer!
Another Happy Customer!

With RockAuto's great selection of manufacturers to choose from, you can get the best part for the job... I have been shopping at RockAuto for many years now and have been recommending them to my friends for just as long.

Dan in Georgia

Upcoming Events
Upcoming Events

Need goody bag items and a gift certificate for your show? RockAuto can help! Email for more information.



The upcoming shows listed in recent newsletters have unfortunately all been cancelled due to current events.




Fab Fours Truck & Jeep Parts
See what we have from Fab Fours is proud to now carry Fab Fours Bumpers, Winch Mounts, Fender Flares and more for trucks and Jeeps! Designed to push the boundaries of innovation and design, Fab Fours offers stylish yet functional parts to fully customize and protect your vehicle from whatever the road or trails might throw at you. Founded in 2004 and based in South Carolina, Fab Fours designs and manufactures all of their parts in the USA.

Fab Fours bumpers are available in a variety of styles like the sleek, lightweight US steel Vengeance Series, the upgraded ranch-style Black Steel Series, the more aggressive Matrix series ($200 rebate on Matrix front bumpers through May!), the ultra-aggressive grille/winch bumper combo (Grumper), and the Premium series made of 3/16 inch (4.7 mm) US steel and including top-of-the-line features such as integrated lights. Durable 2 stage black powder coat paint protects Fab Fours bumpers. Finish the look with complimentary Fender Flares, Roof Racks, Winch Mounts, Cab Protectors and more.

Fab Fours

From Bumpers for a 2017 Ford F-150, to a Winch Mount for a 2008 Nissan Titan, to a Cab Protector for the 2013 Chevrolet Silverado 2500, to front and rear Fender Flares for a 2009 Jeep Wrangler, you can find Fab Fours products for your specific vehicle under the "Accessories", "Body", "Interior" , and "Wheel" categories, all at the reliably low prices you expect from

Dayton CargoMaxx Coil Springs
See what we have from Dayton

RockAuto now carries Dayton CargoMaxx heavy duty Coil Springs. CargoMaxx springs are custom-designed for vehicles used in continuous heavy hauling conditions - like utility vehicles, pickups, SUVs, vans, motor homes and more. CargoMaxx springs are manufactured in North America and feature:

  • Increased load handling capability
  • Improved ride quality and cornering stability
  • Reduced driver fatigue for increased safety

CargoMaxx springs come in both variable and constant rate for two different load options:

  • HD - Designed to carry 35% more load at stock load height
  • XHD - Designed to carry 70% more load at stock load height

Dayton CargoMaxx Coil Springs can be found in the "Suspension" category of the catalog for specific trucks, vans and SUVs built by Chevy/GMC, Dodge/RAM and Ford from the 1970s through 2020.

Forum of the Month

In May of 1999, started out as a tribute to one of America's favorite 4x4 utility trucks. Since then it has grown to become one of the most popular Chevrolet K5 Blazer and GMC Jimmy web sites. CK5 has also expanded to include the classic C/K series, GM Truck and Suburbans as well as past and present GM models.

With its well documented project builds, technical articles, factory specifications, photo gallery, classifieds, active message forum, product reviews and original automotive content it is an unbeatable source for C/K and K5 enthusiasts.

If you are the administrator or member of a forum and you would like to see your website featured in an upcoming newsletter and receive a discount code to share with your members, contact

Repair Mistakes & Blunders
Repair Mistakes & Blunders

My dad had a '99 Cadillac Deville. He was complaining about soft brakes for awhile and even took it into a mechanic a couple of times; paying hundreds of dollars to bleed the brakes and have new brake lines installed. When we had finally decided to sell the car, I checked out the brakes and they still felt soft to me. As this massive car was one of the last big "land yachts," I did not want a buyer to go flying (or would it be sailing?) down the road and not be able to stop this beast as expected. I performed the normal checks, and while looking at the brake master cylinder under the hood, the sunlight happened to hit the fluid reservoir cap just right and I noticed a small crack. Sure enough the seal was split all the way around.

Well, after a $4 part and bleeding the brake fluid, the brakes worked fine. I bet the fluid absorbed moisture and became less effective at doing its job over time. Check the easy stuff first! Also, sold it to the first guy who looked at it.

Mike in Michigan

Tell us about your most infamous auto repair blunder or unconventional fix. Use your woe to help others avoid similar mistakes or share off-the-wall solutions that worked (at least for a while!). Please email your story to Include your mailing address and if you would like a RockAuto T-Shirt (please let us know your shirt size) or Hat if we publish your story. See the T-Shirts and Hats under Tools & Universal Parts in the RockAuto catalog. The story will be credited using only your first name and your vague geographic location (state, province, country, continent, etc.) so you can remain semi-anonymous!

Automotive Trivia
Automotive Trivia

Which vehicle was used as a hearse during the funeral for North Korea's Kim Jong Il in 2011?

A. 1964 Mercedes Benz 220SE hearse
B. Early 1970s GAZ-66B truck, paratrooper version with folding windshield and roof
C. 1975 or 1976 Lincoln Continental limousine

Answer below

Diesel Oil, Flat Tappets & Gas Engines
Tom's Story

"Zinc" or "Phosphorus" on an oil bottle label usually is referring to the additive zinc dialkyl dithiophosphate (ZDDP). ZDDP helps prevent wear, especially where the camshaft contacts the lifter in flat tappet lifter engines. Newer engines (since the late 1980s) have roller valve lifters and therefore do not benefit as much from ZDDP.

The anti-wear benefits of ZDDP were recognized in the 1950s. The oil of the 1950s had only about 300 parts per million (ppm) ZDDP. The concentration of ZDDP in motor oil gradually increased until it reached a maximum of 1200 to 1400 ppm in the 1980s. (More than 1400 ppm of ZDDP in oil actually starts to increase engine wear.)

Unfortunately, it was discovered that ZDDP makes catalytic converters for gasoline engines less effective by gradually coating the catalyst material with phosphate. To satisfy the latest API Service "SN" oil standard, oil manufacturers only put 600 to 800 ppm ZDDP in their oil.

 Valvoline VR1 Racing Oil
Valvoline VR1 Racing Oil

For over a decade, car enthusiasts with flat tappet lifter engines have been debating whether the 600-800 ppm ZDDP in new "SN" oil is enough protection. Oil experts say that it is enough wear protection once the engine is broken in.

The flat tappet lifter equipped engines in my family fleet were all broken in around a half century ago. I still like to dote on my old cars by giving them a little extra ZDDP as long as it does not require too much hassle or extra money. Valvoline VR1 Racing Oil has been one convenient option. It does not qualify for the "SN" rating because it has too much ZDDP and it is "not recommended for extended use in vehicles with catalytic converters."

Another new, less expensive possibility may be the 10W-30 oil made for some of the most modern diesel engines. Some old car enthusiasts have long recommended oil for diesel engines because it frequently contained more ZDDP. Unfortunately, diesel oil was typically only available in a heavy weight such as 15W-40.

Motorcraft's 10W-30 oil for diesels
Motorcraft's 10W-30 Oil for Diesels

The label on Motorcraft's 10W-30 oil for diesels says it "contains more than 1000 ppm phosphorus for better wear protection." That is 200 to 400 more ppm at little or no additional cost compared to "SN" 10W-30 oils. The Motorcraft diesel oil label also says, "do not use in gasoline engines equipped with catalysts."

I am testing the Motorcraft 10W-30 for diesels in the 351 under the hood of my 1971 Ford LTD convertible. However, I am not recommending that anyone else use oils labeled "diesel" in any gasoline engines. Please consult your vehicle's owners manual, the appropriate authorities, legal council, etc. before choosing a new type of oil for your specific engine. (For most vehicles, simply look under "Engine" and "Oil" in the catalog to see manufacturer recommended choices. Oils listed by weight (10W-30, 0W-40, etc.) are found in the "Tools & Universal Parts" tab, under "Engine" and finally "Oil.")

Tom Taylor,

To read more of Toms articles, click this link and choose from story titles on the Newsletter Archives page.

Mark's 1967 Mercury Cougar
Mark's 1967 Mercury Cougar

I bought this Mercury Cougar in 2018 in Washington State from a very friendly guy and shipped it home to Germany. It had been sitting for awhile at the property of the previous owner, and I knew there would be some work to get it road worthy. I did not know that it would take me two years to get it finished. But all the hard work paid off, and I can finally enjoy driving it on our curvy country roads.

And of course this could not have been done without all the parts RockAuto delivered to me. I changed and updated the ignition, fuel system, brakes, power steering and almost the complete suspension. After changing all the mechanical components, I finally rewarded myself (and the car) with a new carpet from RockAuto as well.

Mark in Germany (RockAuto customer for over eight years)

Share Your Hard Work
Do you purchase parts from RockAuto? If so, RockAuto would like to give you the opportunity to have your car or truck possibly featured in one (or occasionally more) of our publications such as the monthly newsletter, collector magnets, RockAuto social media or other commercial use. New, old, import, domestic, daily driver, trailer queen, classic, antique, we want to see them all! Please email with the vehicle history, interesting details, your favorite images (tips for taking pictures of your car) and what parts from RockAuto you have used.

Automotive Trivia Answer
Automotive Trivia

Which vehicle was used as a hearse during the funeral for North Korea's Kim Jong Il in 2011?

A. 1964 Mercedes Benz 220SE hearse
B. Early 1970s GAZ-66B truck, paratrooper version with folding windshield and roof

Answer: C. 1975 or 1976 Lincoln Continental limousine (link to article)

Back up to trivia question