It would seem as though, after it was made and possibly in storage in some warehouse, that some little 4 legged creature moved in. If you think it is not flowing them only one thing to do and to be safe, take it to a radiator shop that can test the flow and or pull the top and rod it out. One thing we so not want with our old trucks is running hot in traffic, parades and just plain hot weather. Bite the bullet now.
