A plugged/damaged catalytic converter is one possibility.
A GMC Suburban requires routine scheduled oil changes and inspections every 7,500 miles or 12,000 kilometers. Every 45,000 miles additional service is required such as changing the automatic transmission fluid, and transfer case fluid. At 150,000 miles a flush of the engine cooling system is recommended along with a thorough belt inspection.
Anytime your coolant level is below the fill line in the overflow bottle, top it off. Anytime the fluid changes color, gets foamy, or otherwise looks dirty; it is a good idea to change the fluid out. Dealer maintenance schedules do not list a Cooling System Flush as required maintenance until 150,000 miles.
You should drain & replace your coolant at least once every 100,000 miles minimum.
Plain green 50% antifreeze 50% distilled water mixture. Have your coolant flushed every 30,000 miles along with your j-matic transmission fluid and differential/transfer case fluids.
Your anti-freeze is a Dex-cool anti-freeze. It is not compatiable with the green kind. It is a long life coolant which can last up to 100,000 miles. If you have to top off, do not add water as this coolant comes pre-mixed. Is there red fluid on top of normal coolant? If so you have a leak between you radiator and auto tranny cooler.
Change spark plugs, replace coolant and thermostat, change transmission fluid and brake fluid. At 170,000 KM or 105,000 miles replace the cam belt if it is a V6.
Your anti-freeze is a Dex-cool anti-freeze. It is not compatiable with the green kind. It is a long life coolant which can last up to 100,000 miles. If you have to top off, do not add water as this coolant comes pre-mixed.
i have a 1996 Chevy suburban with 226,000 miles on it and it runs great so you make that decision
Thermostat not opening fully Water pump not circulating coolant Radiator plugged or restricted
about 10 miles per gallon
A 1991 Chevy Suburban will get 11 miles per gallon if driving in the city. It gets around 15 miles per gallon on the highway.
The 1993 Chevy Suburban gets 11 miles per gallon when driving in the city. This model gets 16 miles per gallon on the highway.