Gurgling water noise from dash

[alistairgd]

A few minutes after start up, I hear a few seconds of water gurgling behind the heater vents on my C180.

Related info : the heater dial goes from 0-28, but 0-20 all feels cold, then suddenly it will start blowing noticeably hot only when it's turned right round to 25. A few months ago the heater element on the thermostat was replaced under warranty.

I'm thinking something is still wrong with this, what with the water noise, and the heater not blowing hot until it's turned 75% of the way up.

Anyone heard of this before?

 

[brucemillar]

Normally "gurgling " is down to air in the system. Probably trapped in the heater matrix. Might be worth trying to give it a good bleed.

With the engine cold.

Get the front of the car as high as you can. Use ramps if possible.
Set the heater to max temp and blowers to full.
Remove the header or rad cap.
Run the engine up to temp at idle and leave running for 30 minutes.
That should force any air out the highest point and also force coolant through the matrix.

Also check that the scuttle drains under the windscreen are not blocked and filling the scuttles with rain water.

 

[alistairgd]

Hmm okay - reading your advice I will add this, two days ago the car was reverse parked up a steep incline for a couple of hours. Also, today the dash is saying "check coolant level".

Thanks.,

 

[brucemillar]

Hmm okay - reading your advice I will add this, two days ago the car was reverse parked up a steep incline for a couple of hours. Also, today the dash is saying "check coolant level".

Thanks.,

So you may well have air trapped in there. As the air moves the coolant will fill the space left by pushing the air somewhere else. The air needs to get out. You will then see a true coolant level and hopefully no more gurgling.

 

[alistairgd]

Also check that the scuttle drains under the windscreen are not blocked and filling the scuttles with rain water.

I've done the easy job, found the little grid on the drivers side at the wiper arm totally silted up.

Just need to get the air out the system as you have described now.

 

[brucemillar]

It is usually only evident that you burped the system when/if the coolant level drops. It is important to let the car run with the cap off from cold up to running temp, then for 30 minutes after that. This allows for the coolant to expand and the water pump to do its job and push the coolant and any air around the system. Remember that a very small amount of air in the correct/wrong place can cause havoc. No different to humans there ;ˆ)

 

[oldguy57]

^^^ Yep do this . My mate had exactly the same problem on his c180. Took a couple of goes with front end lifted and the air came out eventually with no recurring problem.