Car overheating

TONYSBABYGIRL

MEMBER
1997 OLDSMOBILE AURORA
V8
AUTOMATIC
134,000 MILES

On Friday, a little after starting out on an hour trip, the low engine coolant light came on. I was nowhere near a store so I just kept my eye on the temperature gauge. The temperature was fine. Even a little below where it usually is. When I got to my destination there was an emergency back home so I had to come straight home. There was no time for me to stop and wait for the engine to cool. The temperature was fine. Saturday I drove to Walmart, which is about 15 minutes away to buy coolant. Everything was fine. Sunday morning I added coolant. At that time I didn't see any in the reservoir. I drove about 20 minutes away and came back and everything was fine. Later that night I drove again about 20 minutes away and by the time I got there it was just about to be in the red. I had to stop a few times but I made it home. This morning I looked and there was just a little coolant in the bottom of the reservoir. I put cardboard underneath the car and added more coolant. I suppose there's a leak somewhere because there was some on the cardboard but what I don't understand is why would a car not overheat when the reservoir was empty but would then overheat when there was a little coolant in there? That just doesn't make sense to me.

I just checked the cardboard again and it's definitely leaking. Could me putting the coolant in yesterday have nothing to do with it overheating? I don't know too much about cars but I do try to understand why things happen. All I know is that I read the coolant travels back and forth between the radiator and the reservoir. Could it be that me putting coolant in, not only did absolutely nothing to help it because of the leak, but any coolant that was still in the system after the area of the leak was there until last night and that's why it overheated?

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

There are a lot of variables as to why the engine would overheat with a little more coolant in it and not with less in it. Some of the variables would be highway driving versus not highway driving. If you are driving on a highway, the engine rpm's are lower because the transmission is doing most of the work. Also you are at highway speeds so you have a lot of air flowing around the engine cooling it. If you were in town, doing stop and go driving, the engine would be doing most of the work, transmission shifting through gears, and you would not have a constant steady airflow pouring over the engine cooling it. Also it would depend on the load put on the engine. If it was on a nice straight, flat road, there wouldn't be that much of a load of the engine. If you were, say, in the mountains, or a hilly place there would a greater load on the engine as your vehicle climbed the hills. As far as finding out where the leak is, I recommend filling your vehicle's cooling system and doing a pressure test. Here is a link below for you to go to.

https://www.2carpros.com/articles/radiator-pressure-test

Please go through this guide and get back to us with what you are able to find out. We can go from there.

Thanks,
Alex
2CarPros