UPDATE 3-German minister may head to U.S. for Opel talks

* Guttenberg says he expects Opel offers from Fiat, Magna

* Germany's Merkel, others to meet on Wednesday-report

* Fiat CEO visits Opel headquarters, to meet union-report

* Fiat would dump Lancia in an Opel deal-report

(Adds Marchionne to meet German union on Tuesday)

MUNICH/FRANKFURT, Germany, May 18 (Reuters) - German Economy Minister Karl-Theodor zu Guttenberg could travel to the United States at the end of the week to discuss solutions for General Motors GM.N unit Opel, his ministry said on Monday.

"The economy ministry will send a delegation to the United States at the end of the week, if -- after a first examination of the proposals from potential investors -- it makes sense to do so," a spokesman said, adding Guttenberg could head the team.

The German government has given investors interested in Opel until Wednesday to submit their offers for the carmaker, and Guttenberg said he expected offers from Italian carmaker Fiat (FIA.MI: Quote, Profile, Research) and Austrian-Canadian Magna MFa.TO.

He did not say whether there were other interested parties.