ThomasRetUSN

I have a 86 coupe with 96K on the clock. I get the "Low Coolant" light. I have replaced the coolant temp. sensor in the front of the engine block and the coolant sensor on the right side of the radiator. I do not have a scan reader so I can't see if I am getting a code 14 or 15. I do have the FSM.

I need a little help please.

Thanks

cadwiz_01Z

The coolant level switch is located in the radiator, not too far from the fill cap. If the "low coolant" light is intermittent, there may be an air pocket in the system. When you replaced the other two sensors, did you properly "burp" the system?

cadwiz_01Z

To check the stored codes:

put a jumper between pin "A" and pin "B"



turn the key to the "run position" - DO NOT ATTEMPT TO START THE CAR!!!!
you should hear the fans turn on
the check engine light will blink out code "12" three times
(one blink then two blinks - pause - one blink then two blinks - pause - one blink then two blinks)
it will then blink out any stored codes three times each
after the stored codes it will blink code "12" again three times
turn the key to the "off" position
remove jumper

ThomasRetUSN

No I did not. How is that done?

silverja

I had the same problem over the eleven years of owning my '87 C4. I replaced the radiator cap and the intermittent "Low Coolant" light went away. A cheap fix that eliminated the warning light.

abdo

I have an '86 Coupe that had the same problem. Somewhere I read of a remedy. With the engine running and the cap off the radiator, I increased the RPM slightly. The coolant level would drop a few inches. I then poured in more coolant to top it off and then replaced the cap before letting the engine return to idle. I never had the problem again.
It is worth a try.

cadwiz_01Z

You have to let it get up to temp to open the thermostat and circulate the air bubbles to the radiator.

QCVette

I had the same thing twice. My 88 and my 94 would both show the low coolant light. I replaced the cap and it never happened again. I think if the cap is bad, it won't let the system pull in coolant when the engine cools. and eventually you get the light.

My 87 actually had a problem with a cracked head. The cap didn't cure that. (but I wished it would have.)

c4cruiser

One thing to add to this is to raise the front of the car as high as possible using ramps or jack stands. The idea is to get the fill opening on the radiator as high as possible. Any air pockets in the engine will have a better chance of escaping.

Start the engine (cold coolant temp) and remove the radiator cap. Watch the coolant level in the radiator. When the thermostat opens, the level should drop. Raise engine RPM to something like 1100-1200 RPM and fill the radiator to the neck (this is usually referred to "packing" the cooling system). Replace the cap and let the engine RPM drop to the normal idle RPM.

Take the car off the ramps or stands and fill the plastic expansion bottle to the "COLD" mark.

ThomasRetUSN

Thanks everyone. This is why I love corvette's.

pmihaltian

Okay, here you go, Chief. As mentioned above, you need to properly burp your radiator. However, even if you properly burp the cooling system, you can still have an air bubble trapped up under the dome on your thermostat. Sooooooo, use these directions to burp the cooling system AND, drill the two purge holes in your thermostat.

I can tell you that I fought a low coolant light for several years and no matter how diligently I followed the burp instructions, my problem was not totally and finally solved untill I drilled the thermostat holes and THEN, and only then, properly burped the cooling system.

rodj

http://www.corvetteactioncenter.com/...+Warning+Light