There are several things that can cause heater problems in your 1998 Jeep Grain Cherokee. The most common cause of heater problems is low fluid in your cooling system.
the head gasket
A 1998 Jeep Cherokee has disc brakes in the front.
A 1998 Jeep Cherokee uses R134a.
blend door failure is a common problem on 97+ Jeep Cherokee
NoNo
my jeep Cherokee 1998 4.0 is a straight 6
A 1998 Jeep Grand Cherokee has a four speed automatic transmission.
A 1998 Jeep uses R134a.
The correct factory tire size for a 1998 Jeep Cherokee is 215/75 R15.
1985-1996 Jeep Cherokee XJ should interchange 1997-2001 Jeep Cherokee XJ should interchange
The only differences are between a regular Cherokee and a Grand Cherokee.