yesterday evening, when I parked the car in front of a restaurant I suddenly heard a loud ''bang'' followed by a 5' loud hissing sound (sounded like a tyre loosing it's air...) I think it was coming from the driver's front side but I'm not sure.

I went out, checked everything I could see... nothing. No warning lights, engine running smoothly.
I though about a vacuum pump problem but the vacuum pump was not running and everything looked in order.

after dinner I drove about 70 miles to my house, mostly highway, doing 70/90 MPH. Nothing! all sounded perfect, no vibration, no vacuum pump hissing, no tyres pressure warning light, engine temp. showing its usual 90C°... everything was ''as usual''....

I have no idea about what happened.

if anyone here have an idea about what happened your help will be more than welcome!

 

Reminds me of the sound of someone running over a plastic soda bottle.


(Humor) Perhaps your GT's optional factory-installed passenger ejection seat feature malfunctioned? These come standard in the GTC of course

 

No, the parking was spotless! no soda bottles...

I believe that those British cars don't fart in public, chocking indeed... The ejection seat option was too expensive. then forget about both.

seriously, something has happen within the engine bay but...what??

I'm going to drive about 100 miles today and check again if there is a problem.

 

Does someone you know have VAG COM or the like? Maybe see if your car is 'throwing' any code?

 

Hi Ulstrup.

Apart from the bang, the cars do make a noise sometimes as the air suspension levels itself.
I noticed mine do it a couple of times yesterday whilst I was doing a few jobs on it.

Les.

 

Hi Les,

It seems that I found out what has happen.
I managed to speak with a tech. yesterday at Bentley Monaco.

it's a known problem and it's not a problem, actually.

first I have to tell you that, yesterday, when driving on the highway the car worked as it has received an injection of vitamin AND I noticed that, starting around 3/4000 RPM, the exhaust noise was totally different.

the Tech explained me that my car, that he knows very well, was driven mostly around Monaco and that its previous owner has, most probably, never EVER driven it above 100 MPH.
Despite of the fact that it was maintained from day one at Bentley Monaco
they can't avoid carbon deposits to accumulate within the exhaust and since the exhaust valve on my car were barely used, the carbon deposit has, most probably blocked them closed.
the loud ''bang'' was the valve getting suddenly unblocked!and the ''hissss'' was a vacuum noise.
the fact that my driving might be, let say, more ''inspired'' than before have more or less cleaned the exhaust thus the better response and the different exhaust noise proving that the valves are now working as they should.

common problem of a lot of cars in Monaco.

he asked me to come on Monday just to check, but he was quite sure that the valves were the issue.

so, it seems that now I have a cleaner car exhaust and a better sound.... for free

 

That's great news!


Hmmm, next time if any of us get, well, a meeting by... we can tell them per factory instructions we must drive the car 'at speed' to keep things operating properly.

 

Some things just need to be ridden hard every once in a while to keep them in shape. My car won't have carbon deposits but it eats tires.

 

diagnosis confirmed by the dealer, carbon deposit. they injected some kind of chemical to clean both valves through the vacuum pump hole and replaced the two small lines from the pump to the exhaust since they were worn and that was it.
They also found out and replaced a faulty sensor in the exhaust.
everything else tip top.
all under warranty and with their apologies for not checking it before delivering the car....perfect service!

 

great statement, Doc!!
I will have this sentence engraved in 2 pieces of marble and hang them, one in my stable and one in ...my bedroom

 

I think that one went over Steven head. Can't slip one by you. Glad to see all is taken cadre of and not breaking the bank.

 

The 'setup' was far too easy and had a feeling Dr. D would be 'on the case'. I prefer a good, long-lasting challenge. The great success of 50 Shades should be quite instructive, gentlemen.

 

TOTAL THREADJACK!

Talk about hearing strange noises from the back room of that disturbed gentleman off that movie???? So women want a man like that? I thought I was sick and twisted but that dude was off the charts.

I know Steven a bit and that comment was to easy for him. I am just trying not to be to vulgar.

Back to the thread, glad to see the pipes cleared of obstructions.

 

....Now you have given me something more to worry about...Carbon buildup in the Exhaust System...never had the 10Speed over 100 except one time...so now I can expect explosion and big hissss....JimB

 

....Its a rainy Easter here in San Francisco, so today is not the day to blow out the carbon...