Should hybrid owners use a special fuel additive? David Kaiser of LIQUI MOLY says "Yes"

Porsche Cayenne plug-in hybrid crossover. Photo: Porsche Newsroom.

If you drive a hybrid, should you be worried about the health of its internal-combustion “backup engine?”

David Kaiser, head of research and development at LIQUI MOLY, an automotive lubricant and additive manufacturing company based in Germany, says you should.

In a hybrid, the electric motor’s status as the main drive poses key problems for the internal combustion engine, which by definition is used only for short periods as an “assistant”—a role that, depending on how your hybrid is engineered, may function only as a “generator” to keep your hybrid vehicle’s battery charged.

“This results in two problems,” Kaiser says. “Due to the low consumption of hybrids, the fuel remains in the tank for longer and therefore ages more. Gasoline and diesel fuel change their configuration with the effect of air or the oxygen, moisture and temperature therein. This worsens cold start and driving behavior in the longer warm-up of the motors in hybrid vehicles.”

Another problem, according to Kaiser, is that this irregular short-term use results in deposits in the injection tract.

“The fuels are subjected to a natural aging and oxidation because of this. By adding oxygen, the fuel oxidizes. And this can lead to deposits. Overall, the properties of the fuel are worsened by this. In extreme situations, it will eventually become unusable by the motor.”

To address these issues, LIQUI MOLY has developed Hybrid Additive, a product formulated to keep gasoline quality stable, protect against deposits in the injection system, and remove existing deposits.

But can you get LIQUI MOLY Hybrid Additive in the U.S.?

As a German company, LIQUI MOLY might not be a household name like Lucas, STP, or Chevron in the fuel additive world. However, a quick search of the partner locator on the LIQUI MOLY US website showed availability of at least some of their products at both locally owned and national chain parts stores and service centers, including Advance Auto Parts.

However, a search of the Advance Auto Parts website returned only motor oils as available LIQUI MOLY products. And the LIQUI MOLY US website cautions that all products may not be available through all partner locations.

An Amazon search showed more than 230 LIQUI MOLY products available, but no Hybrid Additive.

As a new product, LIQUI MOLY Hybrid Additive may take some time to fully integrate into the company’s network of distribution partners. According to the LIQUI MOLY US website, the retail price tag is US$8.99 for a 100 ml bottle.

In developing a fuel additive specifically for hybrids, LIQUI MOLY appears to be venturing into new territory for the additive industry. Research by Auto Enthusiasts Newsblaster did not uncover competing hybrid-specific products, although there is much discussion on various online automotive forums about the value of using various gas treatments, fuel stabilizers, and other additives with the internal-combustion back-up motors in various hybrid vehicles.