Finally got around to topping off the oil level today, takes ages to get up to temp so I try to do it mid afternoon to avoid annoying the neighbours. I also wanted to check I had successfuly fixed my leaking fuel return union. All good on both fronts.

BUT

When I turned off the engine (very hot by this point) I noticed a distinct fizzing/gurgling/hissing noise almost like frying bacon from around the end of the fuel rails, which took a few mins to go away. I tried to record it but it's not come out very clear. I can't swear it doesn't always make this noise and just happened to notice today.

Any thoughts chaps?

BTW the car is very low on gas/petrol if that makes any difference.

 

oil draining back into the tank maybe?

 

Sounds a little "thin" for that but its not impossible.

Here is the video I made, best bits are 32secs and 51secs. There is a plane flying by at one point but otherwise most of the noises are coming from the engine - which isn't running obviously.

https://www.youtube.com/watch?v=f0i8...e_gdata_player

 

Your vid is set as Private. You need to change the setting so we can view it.

 

Doh thanks, fixed it.

 

Doubt that its "oil draining" back to the tank because the scavenge pump isn't running (engine off) and oil doesn't drain uphill. Maybe crankcase pressure - try loosening (slightly) the oil filler cap next time to see if it has any effect. Examine any pipes/unions that are pressurised whilst running.

 

Just had a look on you tube for you.....very strange bit hard to hear but as Harry says sound more air than oil....& next time do your flys up before you post a video!!

 

Had your air conditioner been on before you shut down?

 

Thanks for the suggestions guys.

I don't have air con so we can rule that out.

Its somewhere between running water (cistern filling) and frying bacon. In my minds eye its like there is fuel boiling or bubbling in the fuel rails. The fuel pump was just getting noisy from lack of fuel so mabey there was a lot of air bubbles in the fuel? Anyway I've just filled her up at the station round the corner, got husband duties this afternoon but after that I'll get it super hot again and see if the noise is still there.

No leaks that I can see, feel or smell in the engine bay or underneath (no undertray fitted).

And I'm not wearing trousers so it cant be that my flies are undone.

 

Hmm bacon sandwhiches!

Is there any smell related to it? Maybe some leaves stuck in the cat heat shield being dried out/cooked?

I was thinking of maybe an Air Con leak like Jim suggests above, but it doesn't look like you have it fitted.

 

Alex, I'm a bit concerned that you are wandering around your garage with no trousers on....

 

Hehe, oh yes, only a kilt gives the freedom of movement required for this kind of advanced mechanical work. Can be tricky if you get your sporran caught though.

 

Have you maybe pinched the fuel tank breather hose that runs to the charcoal cannister? Would mean the fuel tank becomes pressurised and could make those odd noises?

Run it again and after a while undo the fuel filler cap - if you hear a whoosh then that may be your issue.

 

Also did you bleed the fuel rail - maybe you have some air stuck in there?

 

Interesting suggestions, thanks.

I'll have a look at that vent line see if it's pinched.

I didn't bleed the fuel rail, and air stuck in the system intuitively feels like the issue, how would you go about that?