Access data base time date fields

I am trying to use the locate method to search for known dates in a date
time field of an Access 97 Data base.
Borlands data base explorer tells me that it is a datestamp field 16 bytes
When I use a variable of type datetime no match is found.  This variable is
of course only 8 bytes long.
the line of code I am using is

if not Table3.Locate('Week', TempDate ,[]) then

and tempdate was defined as type TDate.

Is this the problem why I annot locate the record with the supoedly matching
date field?
Any suggestions?