Honda Repair: 95 Honda Civic engine rev, honda civic engine, radiator hoses

Question
Hi, I've got a 95 Honda Civic with about 170000 miles on it that's been giving me some trouble. When the car is idling the engine revs up and down between about 1000 and 2000rpm's i think it was. This was happening in the past and my antifreeze was disappearing seemingly overnight. The car was overheating so I took it in to a local mechanic and he replaced the radiator. It's been a good 3 or 4 months since then and now the problem has suddenly resurfaced with the same symptons, engine revving and antifreeze disappearing. I think I also saw some smoke coming out of my exhaust but it may have just been the cold weather. Any advice would be much appreciated!

Answer
Bukola, this is definitely coming from the cooling system at some source. Now that you have replaced the radiator you need to start replacing other components of the cooling system. Radiator hoses should be inspected and/or replaced. Heater core hoses should be inspected and/or replaced. Thermostat should be inspected and/or replaced. Water pump should be inspected and/or replaced. Entire fluid should be flushed after doing repairs and properly bled of all air bubbles in the system. Air bubbles/air masses in the cooling system is what causes the idle to rev up and down sporadically. Bleeding the air out of the coolant system solves this problem. What color was the smoke? Was the car properly warmed up? If you have just started the car then condensation is normal at first. But, if the car is warmed up and still smoky white/clear looking, this is an indication that the head gasket might be going bad as well. Have a Dealer do a compression test on each cylinder to find out.