# Any ideas what this noise can be?



## pabsie (Jan 29, 2009)

Hello .... hope someone can put our minds at rest

We have a Hymer 564 (called Dan) and are ten days into our 'grown up gap year' tour of Europe (or bits of Europe) Dan had a new MOT and service recently but we have noticed a noise coming from the engine when we park up.

It is a sort of groaning sound that lasts for about 3 or 4 seconds every 4 or 5 minutes. It sounds as if a pump or something is trying to kick in.

At first i thought it was something to do with the water pump but we have eliminated all our thoughts by turning everything off and it still rumbles away peridically.

It seems to stop once the engine has cooled down. Could this be a noisy fan?

Anyone got any ideas before we take it to a garage?

kind regards
Paul and Sue


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## Alfa_Scud (Sep 27, 2006)

Hiya Pabsie,
I was going to ask if you'd opened up the engine bay to see if you could see anything. It does sound a bit like it could be a noisy fan trying to kick in, or indeed actually kicking until the bearing gets past the "grumbly" stage.

I would have expected the sound to be more a grumbling than groaning though - if you get my drift.

First off I would try standing over the engine (or looking at it anyway), with the bonnet open to see if there's anything obvious when you hear this noise


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## Fatalhud (Mar 3, 2006)

Power steering :?: :?: 

Alan H


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## pabsie (Jan 29, 2009)

Thanks Chris,

I have looked in the engine bay but nothing apparent, will try again this afternoon, and you're right the sound is more grumbly than groany.

Paul and sue


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## 108717 (Dec 12, 2007)

Stuff that happens when you stop is more than likely to do with something cooling down. My best guess if its a groany rumbling sound is that it is the coolant running into/out of the expansion tank as it should. A kind of flubbly wubbly sound like big bubbles in a plastic bottle. not sure about groaning though but it depends how the system is set up. I've stayed in hotels where the radiators 'groan' as they warm up so it isn't too ridiculous. Does it do it if you only run for a minute from cold i.e. before the thermostat opens and the coolant starts to circulate around the engine? I'm assuming you have a basic grasp of what I'm talking about so i won't patronise you. Feel free to ask for a non-mechanic type explanation if needed.

Alternatively the manifold (where the exhaust leaves the engine) might be contracting as it cools. 

I had an Impreza Turbo some years ago with a monster exhaust on it and as it cooled down it sounded like someone was firing shrapnel at an oil drum. I'm not sure if the fact I liked it makes me a sad petrolhead.


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## gm6vxb (Nov 3, 2007)

Sounds like it is the non return (??) valve in the coolant system allowing air back into the system.
Hava a similar problem with a Citroen but you can only hear it when parked up in a garage.
You could try removing the pressure cap when you have stopped and see if the noise is goes away.
Obvious safety precautions about removing a pressure cap when the engine has just been stopped. 
The system will be under pressure and if it has been filled well up, you will get a good soaking with very hot water, so use a rag over the top of the cap and turn it slowly until you cannot hear any more hissing.


Martin.


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