In a previous thread I read that the float in the expantion tank could stick and give a low coolant message. My problem: after a 50 mile all highway trip stopping and starting on the local roads produced the warning. Riding on level roads no warning. I'm guessing the float wasn't stuck. Picked up some 50/50 mix at a A&P I passed. After the engine cooled down I opened the expansion tank. I could see fuid in the tank and it only took about 4 oz to bring it close to full. Drove the 50 highway miles back home. This morning I checked the expansion tank and it was at the same level I filled it to. At no time did the temp. guage go above the normal mark. Question: is the sensor that sensitive? Will 4 oz low in the cooling system produce a warning? I checked every placed I parked at home and could find no coolant on the ground. 2 years ago I had the system drained and new thermostat installed. Ideas. Jack

 

I had the same thing happen to mine. The sensor seems to be that sensitive.

 

Mine was doing that for a while and I would put about 6oz in. Seemed like a nuisance Then one day the warning came on and I put in about 18oz, and it's been that way ever since. Don't know what changed, but I like it.

 

Thanks guys! Your replies give me some piece of mind. Going to keep the 50/50 mix in the trunk for a while just in case. Jack

 

So far, I keep a pint bottle of 50/50 dexcool equivalent and a quart of engine oil in the trunk at all times.