Interpretation ID: nht93-3.36

DATE: May 6, 1993

FROM: John Womack -- Acting Chief Counsel, U.S. Department of Transportation, NHTSA

TO: L. Schmidt

TITLE: None

ATTACHMT: Attached to letter dated 11-20-92 from L. Schmidt to NHTSA (OCC 8091)

TEXT: Your letter requesting information about regulations that might affect substitution of a diesel engine for a "worn out" gasoline engine has been referred to my office for reply. I apologize for the delay in answering.

By way of background, NHTSA is authorized by the National Traffic and Motor Vehicle Safety Act (Safety Act) to issue Federal motor vehicle safety standards (FMVSS's) that set performance requirements for new motor vehicles and new items of motor vehicle equipment. NHTSA is not authorized to certify or approve motor vehicles or motor vehicle equipment for compliance with the FMVSS's. Instead, under the Safety Act, each manufacturer of a motor vehicle or item of motor vehicle equipment is responsible for certifying that its products meet all applicable safety standards.

We do not have any requirements that would apply to the conversion of a vehicle from gasoline to diesel if the conversion is made by you on your own vehicle. The Safety Act and our regulations generally do not apply to a vehicle after the vehicle is sold to a consumer for purposes other than resale. Although the Safety Act prohibits certain entities from tampering with or removing federally required safety systems, the prohibition does not apply to modifications by a vehicle owner to his or her own vehicle.

If the diesel engine were substituted for the gasoline engine by a vehicle manufacturer, distributor, dealer or repair business, the installer would not have to certify the vehicle as described above. Instead, S108(a)(2)(A) of the Safety Act requires any of these parties making the substitution to ensure that it did not knowingly render inoperative any device or system of design installed in compliance with any applicable safety standard, such as Standard 301, "Fuel System Integrity" (49 CFR S571.301, copy enclosed). The purpose of Standard 301 is to reduce deaths and injuries occurring from fires that result from fuel spillage during and after motor vehicle crashes.

The prohibition of S108(a)(2)(A) does not apply to individual vehicle owners who alter their own vehicles. Thus, under our requirements, individual owners may install any item regardless of its effect on compliance with the FMVSS's. However, NHTSA encourages vehicle owners not to tamper with vehicle safety equipment if the modification would degrade the safety of the vehicle.

You also asked if any law forbade diesel conversions in zones within your state in which emissions tests are required. We suggest you contact the Environmental Protection Agency for any questions concerning emissions and air quality. The general telephone number for the EPA is (202) 382-2090. You should also contact the state of Wisconsin for emissions testing regulations.

I hope this information is helpful. If you have any more questions about NHTSA's safety standards, please contact David Elias of my staff at this

address or by telephone at (202) 366-2992.

Attachment: 49 CFR S571.301, Fuel System Integrity. (Text omitted.)