Just before the launch of the Mark 4, the Mark 3's had their front windscreen wiper configuration changed, with a common direction sweep for both wipers.
In 1979 the Ambassadors front went through a major facelift. The front grill is much smaller in height with a larger chequered grill and square park lamps. Now separate amber indicator lamps are incorporated on the semi front lip spoiler below the bumper, which is mounted higher up. This model is named the Mark 4. In addition to the existing petrol version, a diesel variant was launched which is powered by a 1489 cc, 37 bhp BMC B-series diesel engine. It is the first diesel car in India.