March sales of cars and trucks in five South America countries tracked by WardsAuto declined compared with year-ago for the second consecutive month and for the fourth time in the last five months.

Deliveries of light vehicles and medium- and heavy-duty trucks totaled 447,517 units in March, down 1.4% from 453,790 in like-2011.

Thanks to a strong gain in January, sales in the first there months inched pass year-ago to 1.224 million units, up 0.9% from 1.213 million.

But unless results turn around in Brazil, which accounts for roughly two-thirds of the region’s volume, sales soon could trail 2011.

Vehicle deliveries in Brazil dropped for a third straight month in March’s largely due to tighter credit and a newly imposed higher tax on imports. Both issues are expected to continue to have a negative impact on the market.

Venezuela and Uruguay, which combined account for less than 5% of the region’s sales, posted increases in March.

Venezuela’s vehicle deliveries surged 48.1%, following increases of 20.0% in February and 9.7% in January, while year-to-date results jumped 28.9%. This could be the first year since 2007 that the country posts a gain on prior-year. Uruguay’s March sales climbed 8.8%, and results for the first three months rose 3.5%.

Argentina’s string of 28 straight sales gains was broken in March with vehicle deliveries falling 3.6% from like-2011. Year-to-date results grew 5.3% from prior-year.

Rounding out the region, Colombia’s vehicle sales in the month fell 5.5% from a year ago, but its year-to-date total rose 4.0%.