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1999 Cavalier - antifreeze and engine blast?

I have an 1999 Cavalier that I got inspected in July so I’m good until next July. I had a small welding job done on the frame so it would get the inspection sticker for this year, but I’m thinking that by next year, I’ll have paid enough off of my Liberty and be able to take on another car payment. In the meantime, the Cavalier has 214,000 miles on it and has something weird happening. Occasionally, I will get into the car and turn the key to start it and it makes a sound in what I think is the engine compartment. It almost seems as if there is a small explosion in the engine and the car doesn’t start. Then, I turn the key again and it starts up without a problem, no boom. This actually happened again yesterday and I’m writing now so I don’t forget “how” it happened. I stopped at the school to pick up my son and shut off the car to go in. I picked him up, got in the car and that is when it happened. I had just come from my house which is a mile away, so it was a short drive to get him. Not sure if that info helps. I keep thinking that maybe one of the cylinders has some gas in it that is igniting when I try to start it, but not sure what could cause that. It doesn’t happen all the time though, just once every couple of weeks.

Also, this car has over 200,000 miles on it and I do not believe I have ever changed the antifreeze in it. It is the orange kind that is supposed to be good up to 100,000 miles and, yes, I should have had it changed a long time ago, but I have never had any problems with it overheating or starting in the winter time so I didn’t worry about it. Again, this is only once a month or maybe every few weeks, but I’ll see the coolant light come on. I don’t want to take this to the shop and pay them to replace the coolant, so I’m thinking I’ll either do it myself. My question is…should I drain it and replace with orange coolant, green coolant, or just top it off with water? Remember, the plan is for the car to last until next July, but I guess if it needs to go a few more months for me to pay off my other car, I may try to inspect it again.

Thanks.
Jim

My guess is that you’re backfiring. That happens when the ignition system is not properly operating and raw gas is getting into the exhaust system or getting into the intake plenum…and then getting ignited. It can also happen when an injector is not closing properly, allowing fuel to be sprayed when it shouldn;t be…or leaking and allowing fuel to be sprayed at improper times. If the rest of the car has been as poorly maintained as the cooling system, it’s operating on borrowed time.

Start by getting the ECU scanned for fault codes and, codes or no codes, get a thorough tuneup including new sparkplugs, filters, and belts. Plug wires if your car has them.

And change that fluid. purge and refill with the fluid specified in your owner’s manual. Coolant not only lowers the freezing point and raises the biuking point, but it also provides corrosion protection and lubrication to the water pump.

Post back and let us know how you made out.

Really, the coolant is the only thing I haven’t really done. I had the plugs and wires replaced a month ago, and always keep up with the oil changes. I think this weekend I’ll try to do the coolant. Now if I can just figure out why the thing runs so rough. It was running a bit rough at idle and at stop lights so I had the plugs and wires replaced. It still runs rough. Not sure if injector is a problem, or maybe the coil pack is bad on that cylinder. I pulled the wires off the coil packs and one of the coil ends, I think #4, looks a bit corroded. None of the others look bad though. Not sure why that one looks rough, but thinking that could be the cause of the miss.