Coolant Issues

[skrud13]

I am having a problem with my coolant levels and the engine overheating. I have an '88 that seems fine when I first get into it in the morning. I check the coolant level and it is right at the edge of the filler neck on the radiator and the overflow is right at the correct level. Once it heats up, the low coolant light comes on. After that, the temp goes up and down and the coolant temp goes up and down dramatically (190 - 255). I assume that there is a large bubble/void in the coolent, but everytime I open the radiator, the level is right at the top. I tried running it up to temp with the cap off and adding water as the level drops, but the hot spatter makes it near impossible to see if the level is low or not. Some have said run it with the RPM at 2000 while you add fluid as needed, but that is near impossible as well since a ton of antifreeze flows out during warm up. Any suggestions? I am nearly out of patience.

 

[Vettefan87]

Hmm... when I do that to mine and run it at about 1500 or higher the level always drops as I add fluid till its full then I cap it. How long are you running it at 2000 to check for air pockets?
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[Robertwav1]

I am having a problem with my coolant levels and the engine overheating. I have an '88 that seems fine when I first get into it in the morning. I check the coolant level and it is right at the edge of the filler neck on the radiator and the overflow is right at the correct level. Once it heats up, the low coolant light comes on. After that, the temp goes up and down and the coolant temp goes up and down dramatically (190 - 255). I assume that there is a large bubble/void in the coolent, but everytime I open the radiator, the level is right at the top. I tried running it up to temp with the cap off and adding water as the level drops, but the hot spatter makes it near impossible to see if the level is low or not. Some have said run it with the RPM at 2000 while you add fluid as needed, but that is near impossible as well since a ton of antifreeze flows out during warm up. Any suggestions? I am nearly out of patience.

Try running it without the thermostat?