Help! Hissing Sound...

[curlyks2]

Knew I should have stayed in bed...

Started the car (ABY coupe) up this morning, and am getting a hissing sound - like air is either escaping under pressure or being pulled into a vacuum. I suspect some pipe somewhere is split or adrift... but thoughts on which, or other suggestions very very welcome.

The hissing appears to be coming from the very back of the engine bay (closest to the windscreen), somewhere centre/drivers side. It can be heard from both inside and outside the car equally loudly (with the bonnet up at any rate). Sometimes, on switching the engine off there's an air rush sound (like a dump-to-air dump valve, but not). The hissing goes away when the steering wheel is turned (hence putting this plea in the Suspension and Steering forum. It comes back when I stop turning the steering wheel (with the steering wheel in any position).

There's no warning lights, all fluid levels look fine, brakes work without any hassle, and the bomb survives 70+ pushes on the pedal before it goes solid. Drives fine, and the boost gauge tells me there's currently no boost leak(s).

Any thoughts?

Cheers,

Ck.

[audiman]

Does the steering feel funny in any way?? It may be an internal leak in the rack? If it was a small boost hose then it would drive badly. And if it was an external leak it would be fairly visible by the sounds of things.

PAS fluid level is ok?? Rack boots arent full of oil??

[martinjs]

I have a similar problem, it starts hissing if you hold the steering on full lock, and yes my steering feels very odd, as though there is some play in the rack somewhere. Car pulls all over the road.
Ive checked the bolts which secure the steering arms to the rack and they are ok. All new track rods balljoints etc

[audiman]

Martin unplug that servotronic under the rear seat, its on the drivers side.

[martinjs]

Done that already.

[audiman]

Rack mounting bolts loose Martin?? Mine hisses on full lock too, but only right lock IIRC Cant go and test at the moment as it parked outside the pub 3 miles away

[martinjs]

You can drive it next weekend to see what you think.

[martinjs]

Ok, i'll check them.

[curlyks2]

Does the steering feel funny in any way??

Didn't feel any different to normal.

If it was a small boost hose then it would drive badly.

Agreed. It's not driving especially badly. Well... no worse than normal.

And if it was an external leak it would be fairly visible by the sounds of things. PAS fluid level is ok??

Whatever it is, it's certainly audible. All fluid levels appear to be fine - one of the reasons I thought vacuum or pressure line somewhere.

Rack boots arent full of oil??

Um... I don't even know where to look for those!

have a similar problem, it starts hissing if you hold the steering on full lock, and yes my steering feels very odd, as though there is some play in the rack somewhere. Car pulls all over the road.

No pull to either side here. Didn't really get any hiss at full lock - now getting it all the time while the wheel is pointing in any given direction... but not while the wheel is being turned.

Ck.

[curlyks2]

Update: inside the car, the hiss is loudest in the drivers footwell, apparently where the steering dissappears through a big rubber boot into the engine bay. Anyone any thoughts?

Cheers,

Ck.

[audiman]

With no fluid losses then it must be internal in the rack. Thats all i can think of on it.

[curlyks2]

With no fluid losses then it must be internal in the rack. Thats all i can think of on it.

Thanks for that
Got a nasty feeling in my wallet about this one...
Ck.

[curlyks2]

With no fluid losses then it must be internal in the rack. Thats all i can think of on it.

First prize goes to...

Internal seals in the rack starting to leak. The hissing sound is fluid passing around the seal when it shouldn't. Solution: rack out, overhaul, refit.

Ck.

[curlyks2]

Now sorted. Overhauled rack, new PAS pump. Also minor coolant leak fixed while it was in bits. Spending plans in tatters. Oh well.

Side note: Adhoc car review - had a (please don't laught too much) Kia Picanto to drive while my S2 was off the road. Was expecting it to be errmmm very different. It was - but it still wiped the floor with a (new shape) Fiesta in every way - particularly the brakes - vented discs front, solid discs back, and no weight to stop.

Sooooo happy to be back in mine. Until the next time that is.

Ck.

[audiman]

Glad you got it sorted mate. Not that easy to find a fault over the net!!