FRANKFURT, April 3 (Reuters) - Two buyout groups have made final offers for the heat exchangers division of German industrial machinery and process engineering group GEA

G1AG.DE , one of which could be picked for exclusive talks within days, three people familiar with the matter said.

EQT, which is working with industrial services group Bilfinger GBFG.DE , and private equity investor Triton handed in bids valuing the unit at about 1.2-1.3 billion euros ($1.65-$1.8 billion) by a Friday deadline, the people said.

"However, the headline price does not give you the complete picture because almost a third of the unit's roughly 1.5 billion euros in sales is project-business, which comes with guarantees," one of the people said.

Some of the risk from these guarantees may wind up staying with the seller, potentially inflating the sales price, he added.

GEA, EQT, Bilfinger and Triton all declined to comment.

The heat exchangers division, GEA's second-largest business by revenue but last year defined as non-core, makes equipment for a wide range of applications from air conditioning to cooling towers. ID:nL5N0J51PH

In the consortium comprising Bilfinger and EQT, the industrial services group is interested in acquiring the cooling towers activities, while the buyout group would take the rest.

Triton acquired the heat exchanger business of Alstom

ALSO.PA earlier this week. But sources familiar with the transaction said the GEA and Alstom units are so different that few benefits would be gained by merging them. ID:nL5N0MT0UP ($1 = 0.7263 euros)

(Reporting by Arno Schuetze; Editing by Hugh Lawson)

((arno.schuetze@thomsonreuters.com)(+49.69.7565.1197)(Reuters Messaging: arno.schuetze.reuters.com@reuters.net))

Keywords: GEA UNIT/SALE