need to replace low coolant sensor??
Thread Starter
Teching In
Joined: Sep 2010
Posts: 4
Likes: 0
From: East Alton, IL
need to replace low coolant sensor?? I have a 99 z28 vert. with 87K miles. The problem is when car is cold and I first start it the low coolant light comes on and stays on even when it gets warm. When I turn it off and immediately restart it the light goes out and will stay off until it sets and gets cold and I start it again. Yesterday I removed old sensor to clean it and it looked clean except for a little brown slime. I cleaned that off and re-installed it and the light still came on. Today 
I decided today to replace it and went to Autozone and got a new one. Part # SU1302. The instructions that came with it say "The sensor is susceptible to failure if contaminated by oil or exhaust gas. If the original sensor is submerged in coolant yet reports a low coolant level, correct the fault before installing this sensor. Thoroughly flush the cooling system and install new coolant. If the problem continues a faulty transmission cooler, failed cylinder head gasket or faulty intake manifold gasket are suspects for failure. Flush the cooling system and install new coolant when replacing this sensor." Yesterday I did notice the coolant looked like it had a little oily look to it but I had everything flushed with a machine and NTB a few months ago. So there should be nothing in there but coolant. They replaced it with dexcool or its clone. I'm getting it checked out at a garage on Friday to see if I have a bad head gasket or intake manifold gasket. Hopefully someone else has had same problem and can offer some advice. Sorry for writing so much but I wanted to include as much detail as possible. Any help would be greatly appreciated. Thanks
I decided today to replace it and went to Autozone and got a new one. Part # SU1302. The instructions that came with it say "The sensor is susceptible to failure if contaminated by oil or exhaust gas. If the original sensor is submerged in coolant yet reports a low coolant level, correct the fault before installing this sensor. Thoroughly flush the cooling system and install new coolant. If the problem continues a faulty transmission cooler, failed cylinder head gasket or faulty intake manifold gasket are suspects for failure. Flush the cooling system and install new coolant when replacing this sensor." Yesterday I did notice the coolant looked like it had a little oily look to it but I had everything flushed with a machine and NTB a few months ago. So there should be nothing in there but coolant. They replaced it with dexcool or its clone. I'm getting it checked out at a garage on Friday to see if I have a bad head gasket or intake manifold gasket. Hopefully someone else has had same problem and can offer some advice. Sorry for writing so much but I wanted to include as much detail as possible. Any help would be greatly appreciated. Thanks 
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
Low coolant sensors go bad all the time. Sometime late in 2K they finally took them off our cars. Options are to clean it, replace it, or just disconnect it to keep the light off. Make sure you're not actually low on coolant/have air in the system.
How has your PS fluid level been recently. A common issue is a PS cooler leak, which sends PS fluid in to the coolant stream - but when that happens you'll get horrible alien slime on your coolant dipstick.
However - these sensors do just go bad sometimes.
However - these sensors do just go bad sometimes.
