Slooshing water noise from behind dash

[Owl Man]

Is it normal to hear a sloshing water type noise from behind the dash. It happens for the first mile or two after setting off and then seems to go away although can reappear when accelerating away from standstill sometimes. My local garage said not to worry when I mentioned it at the MOT. He said at least the coolant must be circulating.

Bruce

[DJT]

This driver asked the same question................


car-in-flood.gif

[V Mad]

Has the wife been hiding the bottles there?

[Dom]

I don't know if it's normal, but I get exactly the same, have done since I first got the car.
Be interesting to know how to stop it.
Dom

[Another Peter]

My Stag does that too - no idea why...

Regards

Peter

[Andy Rundell]

usually indicates gas in the coolant (you are hearing it do through the heater matrix) good news if it is only a bit of an airlock.... not such good news if it is combustion gases..... i'd be be breaking out the block-tester/sniffer if i were you.

........ Andy

[Owl Man]

Has the wife been hiding the bottles there?

Brings the word Sloshed to mind!

[Owl Man]

usually indicates gas in the coolant (you are hearing it do through the heater matrix) good news if it is only a bit of an airlock.... not such good news if it is combustion gases..... i'd be be breaking out the block-tester/sniffer if i were you.

........ Andy

Cheers Andy. I will be trying the block tester.

[GDPR]

The early Austin Maestro EFI had that problem - the factory mod looked like a stickle brick that had to be shoved into the heater hose next to the matrix inlet...

[pitzey]

mine does it too

[Westfaling]

Interesting.
Whenever I removed the radiator top plug (with the engine cold) there was always an air space above the coolant. The top hose maybe not quite full. The old problem of all the coolant not getting drawn back from the expansion tank on cooling. That air space may be the sloshing noise.
After many years working with hydronic piped systems I've found that if you can hear the sound of running water inside a pumped circulation system - then there's air in it.
Since I changed to a header tank (Volvo in my case) twhen if I remove the top plug the rad is full & coolant overflows.
Nick

[Stagsongas]

Bruce,

Air stuck at the top of the heater matrix is the most likey cause and it can be difficualt to bleed it out. It's worth checking that the supply hose from one of the heads is connected to the bottom pipe of the matrix, and the return hose is connected to the top. This makes for much easier bleeding of the matrix as air will not go downwards in coolant easily.

In extreme cases, bleed the matrix with the engine running, the heater fully set to hot and sneak the (top) return hose off just a smidge at the top of its diameter. The air should bubble out, but sometimes you have to go as far as raising the front of the car with ramps or jacks to encourage the air to rise out. Take care not to pull the hose right off as you'll get a face full. Set yourself up first, get the hose loosened with the engine cold and not running. Also, pumping the system a little by squeezing the top hose can displace air, but only if the top hose is full, if it has air in it that air will compress and there will be no hydraulic pressure created.

Just now and then. difficult bleeding can indicate a partilly blocked matrix, the only cure being thorough descaling/ flushing or replacement.

Or putting up with the sound....

Good Luck

Steve

[Owl Man]

It's interesting to hear that other people are experiencing the same coolant noises behind dash as me. I will try to remove air from heater matrix as suggested by Steve before investigating the possibility of head gasket trouble. I will report back when I've tried your suggested method Steve. I'm working this weekend so may be a few days till I get round to trying it out.

Bruce

[Stagsongas]

Persevere Bruce, and you'll get there.

Good Luck

Steve

[jleyton]

Bruce,

Air stuck at the top of the heater matrix is the most likey cause and it can be difficualt to bleed it out. It's worth checking that the supply hose from one of the heads is connected to the bottom pipe of the matrix, and the return hose is connected to the top. This makes for much easier bleeding of the matrix as air will not go downwards in coolant easily. Steve

Now this is interesting.

I remember one of the first jobs I did when I bought my car was to change all the hoses. In my naievety I removed the heater hoses without noting which one went where.

When I asked on here ISTR that someone said it wasn't too critical, but I wonder if the slooshing sound only occurs if they are on the wrong way, as it may lead to air sitting in the heater. I don't have any noise.

It was said that the parts manual shows them the wrong way round.

Cheers

Julian