I have a Chevy Lumina, 1996, 3.1 engine, 143,000 miles. Three years ago, I had to replace the intake manifold gasket, also spark plugs at that time. Because to the problems associated with the " orange" coolant, I switched to the " green" after having the cooling system flushed. Have had it flushed a second time since due to oil scum in the coolant, probably left over from what the first flush didn't get out.
About a month ago, I had the AC charged as it was not cooling. Soon after, the car starting overheating slowing going up half way and then suddenly clear to the very hot range, heat indicator light comes on, low coolant light comes on. The fans seem to be coming on okay.
Again, I had the engine flushed for a third time as there was still a film of oil in it, also replaced the thermostat at that time. It continues to overheat rapidly and suddenly. Turning on the heater does not help the problem as it only blows cool air. This led the mechanic and I to believe there was an air lock. The coolant resorvoir was overfilled and then suddenly dropped very low but I cannot find a leak, however do get an occasional antifreeze smell. There appears to be no coolant in the oil but there was a slight scum of brown slug in the fill pipe on the radiator.
Today, I had a new water pump (the newest style for this car) put in and took it for a drive out of town but only made it about a mile before the heat gauge topped out again and the heat indicator light came on briefly. Turned the heater on and it only blew cool air. I limped it back home and parked it.
What to do next? Should I have a new radiator put on it? (It's no more expensive than boiling out the present one?)
Don't know if the mechanic did a coolant system pressure check but will ask him. He is as puzzled as I am.
Hope someone can help. I am very frustrated with this car. I can't really trade it off any more than I can afford repairs but I do need my car. It has been very good to me up to this point and I've been driving it over 6 years.
Thursday, May 31st, 2007 AT 11:21 PM