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Matt
Matt, Mechanical Engineer
Category: Ford
Satisfied Customers: 21626
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have a mondeo 2004, there is a loud noise from the engine

Customer Question

i have a mondeo 2004 , there is a loud noise from the engine which does not seem to be related to the engine revs .Sometimes the engine stalls. Any ideas?
Submitted: 8 months ago.
Category: Ford
Expert:  Matt replied 8 months ago.

Hello

I'd agree that checking over the exhaust manifold is a good idea

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

also I'm assuming that this is the petrol V6 engine? can you describe the noise is its rattle or other rythmetic noise?

Customer: replied 8 months ago.
The noise is not a rattle more of an intermittant humming. It affects the engine revs .
the engine is a V6. I have now found that if I increase the revs to 4000 the engine misfires and sounds terrible
Regards
Expert:  Matt replied 8 months ago.

Hello

OK

This could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.

As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane or brake cleaner around each joint in turn. If the engine rev's up you've found your leak.

Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.

Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

It’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine

ve...

Customer: replied 8 months ago.
Ok will try your suggestions.
Expert:  Matt replied 8 months ago.

understood

just get back to me on this post

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