One problem related to radiator has been reported for the 2004 Toyota Highlander. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota Highlander based on all problems reported for the 2004 Highlander.
Was driving on the highway about 60-65 mph when engine began over heating. Pull over radiator was low. Put antifreeze in drove home check was allow again. The next called Toyota dealer, with out even looking they said you probably have a blown head gasket. But when we tear it down and if the head bolts are stripped out it will cost upwards of 2000. 00. So now I have the car in an independent shop. I'am out almost 800. 00 now, and the cars still not fixed. I believe Toyota knew about this problem long before I bought this car. I went on the internet and found the has been happening in 2001-2006 models. I think they should be held responsible.