sloshing sound behind dash/loosing coolant

[tony2311]

A w203 c270 2002, the cars been losing coolant (warning light came on coolant low) 3 times this week after topping up about a pint each time,
its looks like it is near the bulk head but i cant see the leak, when i switch ignition on without starting the car i heard water sloshing about noise, sounds like it is behind dash board for about 10 seconds then it stops. i drive 30 miles this morning and the temperture gauage stay at 80c . Had local garage to check and he couldnt find leak in the engine department,where is it most likely for the leak to be from?

 

[wemorgan]

Are the interior carpets wet at all?

 

[tony2311]

no the interior is dry. there is signs of coolate on the engine tray at the back near bulk head but cant see where the coolant is leaking

 

[verytalldave]

Does this happen only when the aircon is on?
Check and see.
The noise you may be hearing is the aircon unit running itself down.

 

[wemorgan]

The only experience I have of cars losing coolant with no visible leak was diagnosed as a head gasket leak.
But if you can hear water leaking it does sound like a hose is loose.
Remove the undertray and park the car over a piece of cardboard to help trace it.

 

[tony2311]

its at a specialist at the moment and he couldnt find the leak either, he is keeping it overnight with under tray off and see if hee can found it and heard the sloshing noise.
i never turn air con off. the sloshing sound was very noticeable just before starting car in morning, once warm the noise was very faint on restart.
it is definate loosing coolant as there is trace of antifreeze on engine tray

 

[Benzowner]

I had a similar problem on my E300. I could not find the leak at all. It turned out that across the bulkhead in the engine bay is a metal pipe connected at each end by two rubber hoses, that was the culprit, it had corroded and a small hole had appeared in the metal pipe. When I called the RAC, they by passed the metal pipe. There was no sign of a leak though, so where the coolant was going I never found out. The pipe is something to do with the heater, because after the by pass the heater did not work though I could not see why.

 

[dougal74]

If it leaks when cold but disappears when hot then a) something is expanding with the heat and sealing the leak or b) the pressure when running is forcing the leak closed. Sounds like it must be a union/gasket somewhere.

 

[grober]

You haven't got the dreaded Valeo Radiator problem were the cooling coil at the bottom of the radiator for the automatic transmission corrodes allowing coolant and autotransfluid to mix have you? Check the gearbox fluid asap. Don't panic tho as I am not sure if your symptoms fit?

 

[tony2311]

You haven't got the dreaded Valeo Radiator problem were the cooling coil at the bottom of the radiator for the automatic transmission corrodes allowing coolant and autotransfluid to mix have you? Check the gearbox fluid asap. Don't panic tho as I am not sure if your symptoms fit?

The car drive fine and was told by w124 works that my car which has the valeo radiator but will not damage the transmission when is breaks

 

[tony2311]

I had a similar problem on my E300. I could not find the leak at all. It turned out that across the bulkhead in the engine bay is a metal pipe connected at each end by two rubber hoses, that was the culprit, it had corroded and a small hole had appeared in the metal pipe. When I called the RAC, they by passed the metal pipe. There was no sign of a leak though, so where the coolant was going I never found out. The pipe is something to do with the heater, because after the by pass the heater did not work though I could not see why.

sounds like he bypass the heater matrix on your car which is behind the dash. hope its not the same with mine as its a dashboard out job

 

[tony2311]

If it leaks when cold but disappears when hot then a) something is expanding with the heat and sealing the leak or b) the pressure when running is forcing the leak closed. Sounds like it must be a union/gasket somewhere.

still havnt heard anything from the garage but that does sound right. i just had my engine and gearbox replace with use one just wonder if that has anything to do with it

 

[grober]

The car drives fine and I was told by w124 works that my car which has the Valeo radiator but will not damage the transmission when it breaks

I am wondering if Ian and I are talking about the same problem. 2 things can happen to Valeo radiators. 1.The radiator top hose pipe where the top hose goes on can crack and leak--- this would lead to loss of coolant but the autotransmission would be unaffected. 2. the radiator internal transmission fluid cooling coil can fail leading to the transmission fluid and coolant mixing -this eventually leads to gearbox damage. As I said the symptoms don't fit since you have no gearbox symptoms or no sign of oil in the coolant. I suspect however that your car is in the correct time zone for this fault to potentially occur [ unless you have a manual gearbox or the radiator has already been replaced of course?] which is why I mentioned it.

 

[tony2311]

the garage has confirm its the heater matrix. not much luck with this car as it is a dashboard out job. many thanks for your help

 

[BlackC55]

This is so unusual. Are they 100% sure.

 

[wemorgan]

If the heater matrix sits inside the dash I would imagine the carpets to be wet.......but I've only seen this once before on an old Golf, so I've little experience really.

 

[tony2311]

thats what the garage said, my local garage coulnt find the leak either and point out it might be the heater matrix. since the water noise is behind the dash where the heater matrix is mounted. one thing i dont understand is where does the water leak out?

 

[Zulu-Boy]

You need to check that the scuttle drain is not blocked. If it is, then rainwater accumulates and it has nowhere else to exit other than thepollen filter vent - hence wet carpets. The scuttle drain normally accumulates debris which cant exit the outflow, thus blocking it. Worth a look see.

 

[lynall]

Prob leaks out of a/con drains and they may be partially blocked and holding coolant in hence the sloshing sound.

Pretty rare to fail i have changed 2 on landrovers over the years both were over 10 years old and a couple on trucks and thats it in about 20 years on spannering.

Are you sure dash has to come completely out as i managed a dodge on the landrovers still took 3 hours but dash stayed in.

See here http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=203216&M=612%2E962&GA=722%2E640&GM=716%2E648716%2E649&CT=F&cat=69J&SID=83&SGR=045&SGN=01 item 200 is the matrix and 430 is the a/c drain.

Quick google reveals nothing not one hit! only mention is the bba reman site saying leaking matrix damages front sam.


Lynall

 

[Charlie79]

A w203 c270 2002, the cars been losing coolant (warning light came on coolant low) 3 times this week after topping up about a pint each time,
its looks like it is near the bulk head but i cant see the leak, when i switch ignition on without starting the car i heard water sloshing about noise, sounds like it is behind dash board for about 10 seconds then it stops. i drive 30 miles this morning and the temperture gauage stay at 80c . Had local garage to check and he couldnt find leak in the engine department,where is it most likely for the leak to be from?

I have the same problem. Did you find out what was wrong? Thanks