The wife has a 2000 Lexus GS 300 that is making a strange water sloshing sound in the dash. There is not water coming inside the car as others have stated happens when this occurs. I did notice that I am not seeing any condensation draining when the a.c. is on so I am suspecting a plugged a.c. drain line. I am not sure where the drain line is. I know on newer models it is a slotted grommet on the floorboard above the transmission. Not sure if that is where it is on a 2000. I found a line on the passenger side of the firewall that looked like it could be the drain. I tried air and a wire and could not get anything to penetrate so a quit as I did not want to damage anything. Also occasionally the radiator gurgles as if it is overheating but the temperature is normal. Anyone have any ideas ? Thanks

 

Check your coolant level......... It may be low.

 

I’m having the same issue. I checked the coolant level and it was right on low so I filled it. Rikyracer, any updates on the GS?

 

this happened to me and it ended up being because there was a leak in the radiator and the coolant was low. once i replaced the radiator and the coolant was filled to the proper level, the water sloshing went away.

also, the peeps in the GS forum may be able to help more

 

Have an upcoming appointment to get this checked out. I’ll post once I have an answer.

 

It’s definitely low coolant. The coolant level in mine drops over about 12k miles. I would not call it a leak. Fill it (when engine is cold) and forget it until next year. All good.

 

I topped off the coolant (only needed 6-8 ounces) and the issue remained.

 

you need to bleed the system. get the front end of the car as high as possible (jack, ramps, etc.), stick a funnel in the coolant tank and turn the car on. fill the funnel up and keep it full. if there is air in the system, air bubbles will escape through the funnel. it may take a while, but once there are no bubbles, rev the engine to 2-3k rpm and hold it there for a few minutes. more bubbles should come out. once those stop, the bleeding is done. helps to have a friend hold the rpm's so you can keep the funnel full

if you can, use a funnel that seals inside the coolant inlet so the bubbles have to rise to the top of the funnel and not escape before then. it's actually a very simple process if you have a friend helping you.

also, turn the heater on full blast so the coolant is flowing through the heater core as well

 

Good news! After topping off the coolant and driving about 60 miles the issue disappeared.

 

Problem solved on my end as well with a coolant top-off in the overflow...will keep fingers crossed that it was just a bit low and no deeper issues. Thanks!