1998 Chevy Cavalier Suspicious Coolant Leak

Thank you bluelightnin6,

Tonight, we changed the thermostat. After running the car for several minutes, we noticed that the surge tank cap was emitting quite a bit of steam. We thought that now, this would be the problem!

Went to advanced and replaced the radiator cap, no more steam escaped. No leaking happened at this point.

Drove down the road a couple miles, and parked the car for about an hour. When I left, there was a noticeable pool of coolant under the car. I drove back to my house (about 35 miles) windows fogged all the way up the interstate. Got home and left the car running and checked with a flashlight under the car. There was a noticeable leak, consistent drip.

I checked the hoses where the heater core is, it was bone dry. Followed the rest of the hoses, all of them dry - even where we replaced the thermostat. Checked the water pump, it was not the source of the leak.

When I shut the car off, there was still a leak.

I am beginning to think it is the surge tank itself. I poured water down the side of the tank, and where the water dripped was exactly where the pool was beginning to form. (It is dripping a couple inches in from the front right tire.)

It's awfully dark now, and nothing is open. I am going to take out the tank to tomorrow to inspect. I will advise.

(But I still can't figure out why, now, there is noticeable amounts of leakage - when nothing happened when we pressure tested it?)

I never noticed a leak until after we changed the thermostat and replaced the surge tank cap.

I finally got around to checking the tank. It is definitely not leaking from the tank. It was broad daylight which helped me see into the engine compartment. I noticed that it wasn't leaking with the car shut off, even after filling the tank back up. However, once I started the car and let run for a couple minutes, the leaking began again. Definitely Dex-Cool.

I checked all the hoses and lines again, from the heater core to the block, radiator, water pump.

It seems like the leak is coming from under the motor. Leaking mostly where appears to be the back right corner of the motor, but I don't see any hoses or other pulleys.

I don't think it's a head gasket. No white smoke from the tailpipe, and the guy I took it to before checked the spark plugs and he didn't think so either. I can't see under the car where exactly the leak is because I can't fit - nor do I have a way to lift the car.

If you have any ideas please shoot them at me. I'm going to try to take it back to the guy from before now that we have a noticeable leak.

Im afraid you are probably right. I'm gonna suck it up and take it in to the professionals. Thanks for your help, one last thing. Any idea what I can expect to pay for that kind of repair?