Water pump

Hi all I am getting a strange noise from my engine bay now and again like air coming from a ballon whilst squeezing the neck. (if you know what I mean). It only happens now and again so it would be difficult to take to my mate (mechanic friend that does not charge arm and a leg). It sounds like it is coming from the passenger side of the car. My thoughts were of either fuel pump or water pump. Whats your thoughts people.

And Merry Christmas everyone.

The waterpump is the drivers side and the fuel pump is deep in the fuel tank, so I think any noise from there would be muffled.

One thing I can think of is the the charcoal cannister, which is only activated every now and then. There could be a slight blockage or loose connector.

Miketf160;6316 wrote: Hi all I am getting a strange noise from my engine bay now and again like air coming from a ballon whilst squeezing the neck. (if you know what I mean). It only happens now and again so it would be difficult to take to my mate (mechanic friend that does not charge arm and a leg). It sounds like it is coming from the passenger side of the car. My thoughts were of either fuel pump or water pump. Whats your thoughts people.

And Merry Christmas everyone.

The fuel pump is directly behind the passenger's head, but the water pump is on the offside of the engine.

My first guess would be the alternator belt, but that's on the offside too.:dunno:

Does it happen under any particular conditions?

Here is an excerpt from mgfcar.de. May explain things a bit better.

Evaporative Emissions (EVAP) Cannister Purge Valve
The EVAP cannister purge valve is located in the engine compartment on the rear bulkhead. The purge valve is connected via a flexible pipe to the inlet manifold. The cannister purge valve consists of a solenoid operated valve which is controlled by the ECM using a 12 volts PWM signal. The EVAP cannister purge valve controls the flow of fuel vapours from the EVAP cannister to the intake manifold of the engine.

When the vehicle is being driven the ECM will purge the EVAP cannister by opening the cannister purge valve, this allows the vacuum present in the intake manifold to draw fuel vapour from the cannister into the cylinders for combustion. When fuel vapour is being removed from the cannister, fresh air is allowed to enter via an automatic one-way valve, this makes the cannister ready for the next ’absorption’ phase.

The amount of fuel vapour which enters the cylinders can affect the overall AFR, therefore the ECM must only open the cannister purge valve when it is able to compensate by reducing fuel injector duration. The cannister purge valve will only operate under the following conditions:
• Engine at normal operating temperature
• Adaptive fuelling enabled
• Closed loop fuelling enabled.
When filling the fuel tank, air trapped in the fuel tank by the rising fuel level is allowed to vent to the top of the filler neck by a separate breather pipe. With the filler cap in place, fuel tank breathing is via a two-way breather valve which allows expanding fumes to exit the tank. From the two-way breather valve, fumes are directed to the evaporative emission cannister where they can be purged into the engine via the evaporative emission cannister purge valve.

Evaporative Emission Cannister
The evaporative emission (EVAP) cannister contains charcoal which absorbs and stores fuel vapour from the fuel tank while the engine is not running. When the engine is running the vapour is purged from the cannister into the engine and burned. The EVAP cannister is purged when the EVAP cannister purge valve is opened. Manifold depression draws fresh air into the cannister through the charcoal, which releases fuel vapour into the throttle housing.

So, basically, every now and again the sytem sucks air through using a vacuum from the plenum. If there is something wrong, like a partial blockage, crimped pipe, or a pipe with a hole in it you could get a balloon type noise. It's the only thing I can think of that sucks or blows occssionally (I just know that will get quoted somewhere :shake:).

Your a star CJJ thanks that does sound about right as it only happens for a short time and only when the car is warm. It is my fault as I did say the other day that the car was running really well. I dont suppose you have a picture of were it is in the engine bay do you?

You can see it in this pic. Bottom right, just to the right of the ECU. The one with all the pipes coming out of the top.

The water pump on my F was playing up when I first got it and would sometimes make a noise like a boiling kettle - when this happened if I left the engine running and stopped the car, I could see the coolant dripping out.