Pennzoil's Most Frequently Asked Technical Questions

On our toll-free Pennzoil Technical Service Hotline, we are often asked general interest-type questions as well as those pertaining to specific situations. Listed below are a few of these general questions and our answers that you just may have been wondering about:

1. What makes Pennzoil an outstanding product?
2. What happens if API GL-5 gear oil is used in an API GL-4 gear oil application?
3. What are the GLS products and why doesn't Pennzoil have equivalents?
4. Does Pennzoil have paraffins which cause sludging while other brands don't?
5. How does a VI improver thicken at high temperatures but not thicken at low temperatures?
6. What is TBN?
7. Why do we really need lighter viscosity oils?
8. What is the relationship between the API GL specifications and limited-slip?
9. Where can we use Pennzoil GearPlus® Super 75W-90?
10. What is the difference between DEXRON®-II and DEXRON®-IIE? What about DEXRON®-III?
1. What makes Pennzoil an outstanding product?

Pennzoil starts from the beginning with good relationships with the auto manufacturers, both in the U.S. and abroad. Through these relationships we develop unique additives that meet current specifications, as well as upcoming specifications before they are required. This is how we were able to be first to meet all of the following standards.

Examples of our unique additives include Z-7®, and the Pennzstar® molecule which provides excellent viscosity and thermal protection properties.

Our research laboratory, where all Pennzoil motor oils are developed, has been ISO 9002 certified by an independent auditor. This assures that the procedures we use to develop products are properly documented and have the highest consistency.

Pennzoil manufactures, and therefore controls the quality of its base stocks. We are investing over $250,000,000 to produce now the high quality pure base stocks that will be required for the future.

Pennzoil has an excellent network of sales representatives, packaging plants, distributors and distribution centers to get you the quality product you need when you want it.

2. What happens if API GL-5 gear oil is used in an API GL-4 gear oil application?

API GL-4 and API GL-5 products typically use the same extreme pressure (EP) additive system, with the API GL-5 having about twice the concentration of a API GL-4. In service, these additives become active under extreme load and temperature when the protective oil film can be squeezed away. EP additives work by forming wear-resistant compounds with the metal of the gear tooth surface. As the gears mesh, these compounds shield the gear teeth from direct metal-to-metal contact that would cause wear and damage to the gears. If too little of the active additive is present, proper protection would be compromised. Too much of this additive could cause excessive chemical corrosion of the gear surface. If an API GL-5 gear oil is used in a application where API GL-4 gear oil is called for, chemical corrosion of "yellow metal" components may occur, such as bronze synchronizers, brass bushings, etc. This may lead to shifting difficulties or shortened equipment life.

3. What are the GLS products and why doesn't Pennzoil have equivalents?

GLS stands for Gear Lubricant Special and this is usually a product available only from the original equipment manufacturers. General Motors has several GLS products, and various other manufacturers also have their own. In order to meet our customer's needs, we now offer GM Synchromesh fluid which can be used in place of GM P/N 12345349. At this time, this is the only GLS product equivalent that we offer.

4. Does Pennzoil have paraffins which cause sludging while other brands don't?

Sludging is prevented by, not caused by, the use of paraffinic oils. Pennzoil as well as all other major motor oil producers use paraffinic base oils to produce motor oil. This type of base oil has advantages over the other types of mineral oil available, which is why they are universally used. The only exceptions are synthetic motor oils, which of course cost much more than mineral oil based motor oils. Synthetic base stocks are 100% paraffinic. Technically, paraffinic oil is a term used to describe the chemical structure, not the wax content. Through dewaxing in the refinery and the addition of pour point depressants during blending any harmful effects of wax are eliminated or neutralized.

5. How does a VI improver thicken at high temperatures but not thicken at low temperatures?

A VI (Viscosity Index) improver can be thought of as a very long string which at low temperatures is tightly coiled into a small ball and floats suspended in the oil with little effect on the viscosity of the oil. At high temperatures this ball expands and uncoils and encloses a much larger volume of oil within its structure. This effectively prevents the oil from thinning because of the greater volume taken up by the expanded balls of VI improver molecules.

6. What is TBN?

TBN stands for Total Base Number. It is a measure of the ability of an oil to neutralize the acids that enter the crankcase as by-products of combustion. A base neutralizes an acid, so the higher the TBN, the more acid can be neutralized. With today's low sulfur fuels, TBN is not as much of an issue as it was several years ago.

7. Why do we really need lighter viscosity oils?

Most late model engines were designed to use lighter viscosity oils compared to older models, which required a thicker film of oil to provide proper separation of parts, such as main bearings from the crankshaft. Oil passages were larger to accommodate these thicker oils. To take advantage of the fuel economy benefits of lighter viscosity oils (SAE 5W-30, SAE 10W-30), late model "low friction" engines are designed with smaller oil passages and film thickness requirements. Lighter viscosity oils also flow much more quickly at engine start-up especially in cold weather. Severe engine wear can result if oil fails to circulate rapidly to critical areas. Lighter viscosity oils also circulate more efficiently through the engine and remove heat faster.

8. What is the relationship between the API GL specifications and limited-slip?

A gear oil suitable for limited slip applications (listed as GL-5* or HP* in Chek-Chart Lubricant Recommendation and Capacities Guides) is an API GL-5 gear oil containing limited slip additive. This is a requirement for most differentials with limited slip traction control.

9. Where can we use Pennzoil GearPlus® Super 75W-90?

This is a synthetic API GL-5 gear oil which is used in automotive service in applications where cold shifting is a problem, or where a SAE 75W viscosity grade is recommended.

10. What is the difference between DEXRON®-II and DEXRON®-IIE? What about DEXRON®-III?

DEXRON®-IIE is an automatic transmission fluid specification from General Motors and is an upgrade and replacement for DEXRON®-IID, with the major difference being far superior low temperature flow properties. There is also improved high temperature oxidation and wear protection. This product was necessitated partly to facilitate shifting at low temperatures in electronically controlled transmissions.

DEXRON®-III is the latest automatic transmission fluid specification issued by GM, and fluids meeting this specification can be used in all GM ATF applications including those calling for DEXRON® through DEXRON®-IIE. The enhanced frictional characteristics of DEXRON®-III are different than previous automatic transmission fluids and have been developed to provide smoother shifting for a longer period of time.

For more information on these and other topics, remember, Pennzoil Technical Service is only a phone call away - 1-800-458-4998.

Mike Maddox
National Manager
Technical Service