* Mexico's car exports fall 15 percent in August
* Biggest fall in car exports in 3-1/2 years
* Non-auto, factory-made exports rose for month
MEXICO CITY, Sept 26 (Reuters) - Mexico's trade balance slid into the red in August after a surprise drop in car exports, bolstering expectations for slower economic growth in the second half of the year.
Total exports fell 0.33 percent in the month, the national statistics agency said on Wednesday, with a 15 percent drop in car exports - the biggest drop since January 2009 - overwhelming an increase in oil exports.
Imports rose 1.24 percent in seasonally adjusted terms, helping to push the trade balance into deficit to the tune of $175 million. That compared with a downwardly adjusted surplus of $304 million in July.
The drop in exports, after a recovery in July, is a worrying sign for third-quarter growth in Mexico, Latin America's second-biggest economy, after the pace of expansion eased in the second quarter on waning consumer demand in the United States, which absorbs most of neighboring Mexico's exports.
"Mexico is starting to feel the impact of softer global conditions and particularly in the U.S.," Morgan Stanley economist Luis Arcentales said.
While there was a similar fall in exports in the third quarter of 2011, U.S. inventories bounced back at the start of 2012. "We don't see that being repeated this time around," he said.
Mexico's non-automotive factory-made exports rose 0.07 percent last month from July.
Car exports have been a mainstay of Mexico's recent export gains, with Mexico now the fourth-biggest exporter of cars globally and the country attracting new investment from companies including Audi, Mazda and Nissan.
Still, the fall followed record automotive exports in July and the statistics office said that in non-seasonally adjusted terms, car exports were up 7.8 percent year-on-year.
The Mexican Auto Industry Association Mexican said earlier this month auto exports rose in 10.8 percent in August from the same month a year earlier.
Economists can also draw some hope from the fact most imports were of intermediate and capital goods, which should benefit local industry and exports down the track.
In non-seasonally adjusted terms, Mexico posted a trade deficit of $979 million.