I had an interesting beep today. While slowing to a stop at a traffic light, my Add Coolant Alarm went off. I had been driving at highway speed (60 mph) for about an hour or so in relatively cool spring weather (56 F / 13 C). I had not been pushing the car hard in any way.



I pulled over PDQ thinking that I was in for the worst under the hood, but I found nothing. No steam, no smell of hot coolant, nothing. I checked the coolant level and it was at the F on the stick. I had about 12oz of a 16oz bottle of Aquafina with me and I poured it into the filler neck only to see about the same amount of coolant overflow onto the ground.



After waiting a bit, I started the car back up and continued on down the highway without any more alarms. I drove for another hour or so with a mix of highway and city driving; nothing, no alarms, no steam, no discernible reason for the alarm to have been triggered in the first place.



The car is a 94 Touring and has been kept completely stock.



Any thoughts or experiences is appreciated.

id have the cooling system pressure checked, if it happens again.

Thanks for the tip. Any idea where the sensor is for the add coolant alarm?

Check the wires for the level sensor. when they come under, or short, the alarm will sound. Good luck!

Yeah, I am suspecting this to be a wiring issue. The brittle vacuum lines were replaced last year but the previous owner did not address some crispy wires. Any recommended grade/brand of wire for the engine bay?

exactly..... most likely it is a brittle wire leading to the sensor. Mine went off intermittently for over a year... but with the bridgeport, you couldn't hear it. https://www.nopistons.com/forums/pub...DIR#>/wink.gif

Not really.. I've never heard of special grade wires.. i wouldn't worry too much about that. Just replace them with whatever wires in similar size.

So for giggles I took the car for a spin today but before I did, I popped the hood and looked into the filler neck; where normally I see 'green', this time it was dry. I topped it up with about 300ml of water (not a lot I know). Before I put the cap back on, I started the car and surprise, surprise, champagne bubbles.



I had no idea about champagne bubbles until now.



What I believe happened on my Sunday drive was the coolant was indeed low. While I was pulled over looking under the hood, I added water to the overflow bottle (useless as the excess just spilled on the ground) but maybe as the engine cooled, the system pulled enough liquid back from the overflow to keep the sensor happy for the rest of my trip.



Is this likely?



Given the mileage (84,000 miles) I know I will be on the hook for a rebuild but with the 'bubbles', how much longer can I expect to get with this condition?

Alot of things could happen.. Unless you go thru all the possibilities, its hard to say..



your engine might be ok... I would watch your water temp and see.. If you start to over heat, then do a coolant pressure test done. Until you start over heating and such, I wouldn't worry too much about bubbles.. could be other reasons that could cause that.. Think positive before start thinking about rebuilding and such..

I took my car to a local shop this afternoon and they did find and clear a blockage in the line between the AST and the overflow bottle. They asked me to run the car for an hour or better and then bring it back after a 'normal' drive to determine where the coolant level is at. They suspect that coolant is/was not making it back to the block when the engine cools.



More to come tomorrow.