2000 Chevy Cavalier Problem!!?

[ams007]

I have a 2000 Chevy Cavalier and I am having a problem with it.

Here's all that has happened:

Last year I went to college and I took my car with me. One time I drove it and I realized that it was overheating, so I stopped driving it until I could have my dad take a look at it. He came and put coolant fluid in it, because it was very low. I thought this was strange because I had just bough the car a few months before that and I figured it should have had coolant in it. After this I kept driving it and it was fine.

Then over summer, I took it to get it's oil changed at Walmart. I have had many people tell me that I shouldn't have taken it there, but it is quick and I have a busy schedule so it was the easiest thing for me to do. Right when I pulled up they were not too enthusiastic about doing my car because they were doing nothing at the time, and shortly after I got paged telling me my car was done. The mechanics told me my oil was milky and smelled like gas so they were unable to change it.

After this, I had a couple people check out my car and oil (not a car person or dealer) and they said my oil was fine and didn't smell. So, then I took it to an actual place that does oil changes(Penziol) and they changed it fine, and said nothing about the oil being milky or smelly. From then on I have been keeping eye on if my car overheats and the fluids and so far, it has been driving fine.

Just a little bit ago, I went to start my car and it wouldn't start. So, I kept trying, and I saw the low coolant light on, and it started, but it was shaking really badly. I am not good with cars, so I have no clue what could be wrong with it.
Any ideas?

Any help would be greatly appreciated!
Thanks:)
nope, it doesn't smoke at all
thanks everyone:)

[MPEA]

most likely a blown head gasket,chances are the thermostat stuck at some point,causing the first overheating,and causing the gasket to blow into a water passage in the head,you were probably losing antifreeze out of the over flow,the best way to tell is take it to a reputable mechanic and have him do a compression check,this measures the pressure in the cylinder and if it is low ,most likely thats what it is.another way to tell on that model might be to have someone check your head bolts that are accesible without taking anything apart.i did one of these and broke the headbolts loose with a 3/8 ratchet with very little effort,and sure enough the gasket was blown.in any case if your dad can do it the gasket alone is about 15.00 .the bolt set is about 26.00.if you have to take it somewhere its probably about 300.

[biganess]

I know your concern, let's look at 2 approaches. First, it sounds like you were a victim of lazy workers at Walmart. Do not put too much stock in what they said. After all, how can you tell if your oil had a milky solution to it if they never took the oil out. As a mechanic you can't tell by just looking at or smelling the dipstick. Additionally, what creates the milky solution in oil is anti-freeze, it will look like snot, which indicates a blown headgasket or cracked block. In either case usually you will not drive the car very far. As far as your overheating issue, sounds like you had a stuck thermostat. The heat of the engine will cause boil over and evaporation of the glycol in the antfreeze making the antifreeze level drop especially if your thermostat started working properly and refilled your block with antifreeze from your radiator. Second, if you did blow a head gasket that would definitely cause the engine to run rough because you are trying to combust a mixture of antifreeze and gas in each cylinder, but 99.9% of the time you will get a check engine light usually from the oxygen sensors being coated with burnt antifreeze and you will definitely get a weird odor. Turn your heat on and see if it stinks. See th elink

[james d]

Take it to the shop and have your coolant system pressure tested because a car doesn't just get low of coolant . It had to go somewhere. Then they should check to see if you may have a possible head gasket leak.That would be the only way gas and coolant can get in your oil