One problem related to radiator hose has been reported for the 1999 GMC Blazer. The most recently reported issues are listed below.
The oil cooling lines have been leaking for quite a long time, as a routine the oil level is checked often. After contacting a gm dealer's service dept they told me it is a very common problem with this Blazer and with the truck no longer under warranty to contact the delivering dealership. Besides these hose assemblies are on back order I was told, which means it is a common problem and it may be a matter of time before oil fires may erupt if the line completely fails. After contacting the delivering dealership they will be glad to replace the hoses for $375, in which I would replace myself, but no parts available.