Owners of hundreds of thousands of Ford Motor Co. passenger cars and light trucks and of 12,080 motor homes built on Dodge truck chassis have been warned of defects in those vehicles.

The National Highway Traffic Safety Administration last week said it is investigating defects in the engine cooling fans of an undetermined number of Ford, Mercury and Lincoln passenger cars and Ford light trucks made between 1970 and 1977.

Following the agency's announcement, Ford said it would recall about 400,000 1972 Lincolns, Ford Torinos and Mercury Montegos with air conditioning and 302,351 and 400 cubic-inch engines and flex-fans.

Ford said it would notify the owners by mail, beginning June 22.

The safety agency said the blades on the engine cooling fans in question could break off, causing damage to the cars as well as serious injury to individuals.

If the blades break while the car is in motion, they could sever hoses or dent the hood. If they break during maintenance, but while the engine is running, they can cause serious injury to individuals.

The agency said its investigation should determine if other vehicles should be recalled.

And Chrysler Corp. last week said it has begun recalling 12,080 motor homes built on the 1976 and 1977-model Dodge truck chassis because of a brake problem that could cause the front wheels to lock.

The auto maker said it already has reports of 16 wheel lockups, but none resulted in accidents or injuries.

The M3 and M4 dodge truck chassis were built between March 1976 and September 1976. They were sold to outside manufacturers for the installation of the motor home shell.

Chrysler said the front brake caliper attaching bolts on the vehicle may loosen due to improper assembly or inadequate bolt torque. The loose bolts could back out, interfere with the disc brake rotor and result in lock-up of a front wheel.