I have been hearing a "sloshing" sound behind my dash when cold starting my LR3 and at acceleration for a couple months. I went and had the coolant system pressure tested and a leak was reveal in the water/coolant housing assembly. The job took a few hours to replace with my 13 yr old son and was a fun job to do together. We bleed the system and everything was great for a couple days. The sloshing sound was gone. Until it wasn't. The sloshing sound is back and I'm wondering if I had TWO issues. (1) the coolant leak found with the pressure test and (2) a bad heater core. That is my guess. Would the heater core create a sloshing sound like this? Doesn't seem like too bad of a job to replace myself. I'm not seeing any dampness in the passenger floorboard. I appreciate any direction.

 

You may not have dampness on the floor boards, but I would check the core drains. If they are not draining the core box can fill up with water. Really easy to get to the drains, just pull the inside foot kick panel that has carpet on it. It comes to a point near the cup holders. Yank it hard to remove, then you will see a rubber drain hose. Pull the rubber tab on it towards then downwards. If any water comes out, that's your problem - drains are clogged.

 

Thanks DakotaTravler. I investigated this morning, pulled the carpet kick panel off and see a rubber hose with a rubber pull tab. Is that the drain? Seems like it is for the AC evaporator. That rubber tube is not near the cupholders. I would think I would have to remove the entire dash/center console to locate the drain tubes for the heater core. What am I missing? Thanks in advance!

 

The AC core and heater core are in the same box. I did not say the drain tubes are near the cup holders, I was saying the kick panel to remove comes to a point near the cup holders - just to orientate yourself.

 

Thanks for clarifying. Attached are the drain tubes I checked on both driver and passenger sides. Are these the drain tubes you are talking about? One of them had a lego wedged in it.

 

Yes. If you pull em and nothing comes out, then the sloshing is not from the box being full of water or coolant.

 

Thanks. Yes, totally dry. Issue is farther up in the system.

 

I wanted to give an update on the sloshing sound behind dash and describe a new issue. I had the heater core flushed and the coolant system bled again, both manually and with a vacuum. The heater core flush did result in some debris being removed and now my heat works on both driver and passenger side. Also, the sloshing side is gone. That is the good news. Now for the bad...

After multiple bleeds, I drove the car for a few minutes with the AC off and the windows down. Everything was going great. I then turned the AC on and my temp gauge immediately spiked and I turned around to go back home. I opened the hood and noticed that coolant had bubbled over out the expansion tank. My first thought was a bad cap, so I bought a new one and waited until the next morning to try again with a cold start.

With new cap, I took the car for a spin and after about 10 minutes the temp gauge maxed out and coolant was pushed out of the expansion tank again with the NEW cap. Now the car is overheating with or without AC running.

I'm at a loss. The water pump is working, the fan clutch is new and the system has been bled off an on for a week. When I had the sloshing sound, the car was not overheating. Now I don't have any sloshing, but the car is overheating.

My next idea is to change the thermostat in the water/coolant assembly. It is easy enough and I have one on hand.

Any thoughts would be much appreciate!

 

Certainly check the t-stat, but air in the system can easily cause overheating also. If there is enough air still trapped in the system, then the coolant can expand enough to boil.

 

Thanks Dakota. Do you find it strange that the system has been bled several times over a week and there still be air in the system?