The heater core under the right side of the dashboard may leak engine coolant which can puddle on the passenger front floor. The loss of coolant may cause an engine overheating condition. Our technicians tell us that removal of the dash board is necessary to replace the heater on these vehicles.Google+
Car Problem Reports
GMC Sonoma Heater Core Under Right Side of Dashboard May Leak Engine Coolant
GMC Sonoma Problem
Average Mileage: 135,513 mi (110,000 mi - 155,000 mi)
Visitor, 1996 GMC Sonoma, 148,000 mi
heater wasn't working so disconnected it for a while. after reconnected, leaked massive amounts of fluid (about 1/2" on passenger floor) so disconnected it again. need to pull dash and fix as it's winter and no heat is no fun.
Visitor, 1991 GMC Sonoma
coolant leaked onto passenger side floorboard.. estimate was $350-400. had to take apart dashboard
Visitor, 1991 GMC Sonoma, 155,000 mi
I have to check coolant daily. The windshield has a permanent foggy, moist appearance. I am waiting for the weekend to fix it. It's Wednesday today.
Replaced heater core - 5 hours and 100000 screws later the heater core is replaced and my fingers are bleeding engine coolant.