I drove my 87 na a/t rx to school today because in the suburbs where I live, we've gotten snowed on a lot and today the roads were fairly clear. I keep my car in the garage so no problems driving to school (except the usual seat belt was on). After school, I was fairly worried how my car would deal with the weather (it's first day in snow in it's whole life because its from FL). It started fine, but the idle surged. That was an easy fix I already knew that one. I let it warm up for a few minutes then left. A mile down the road, the ADD COOLANT light a buzzer go off and I'm thinking ****, I blew a seal or cracked the block. I pulled over and the coolant overflow/reserve tank was empty. I filled it back up with peak 50/50, started it...BUZZ. I let it run for a few more minutes and the buzzer and light turned off. I marked a line in pencil where I filled the tank to and drove it home no problem. It's now about 6 hours later and I checked the tank and it is a little lower but not alot. I then did a compression test and got 115 in both rotors. What happened to my car this afternoon?

 

Drew all it could from the reservoir and then pulled in air. You refilled the reservoir, then it sucked in some coolant to replace the air. So far there doesn't seem to be a problem. Just fill it up to the "full" line again and it should stay there now unless you have a leak. If you lose more coolant then you have a leak you need to fix. If so check the hoses and so forth for white-ish dried out coolant

 

Absolutely normal. Fill the overflow bottle to a little pass full, close everything run the car up to normal operating temperature (~10 minutes) disregard warning buzzer, then just leave the car off till it cools itself off completely. It should bleed itself out. The buzzer is just responding to air in the system, no biggy.

 

Brave. I never drive the 7 here in Chicago when the weather dips below 45 degrees.

 

+1 air in system.

Or maybe the car is telling you it doesn't like winter and wants to be stored?

 

1) The great advice above
2) Inspect your hoses
3) Inspect the area where the gasket is for the Water Pump Housing to Engine is.