Hissing engine

JohnCKL · Post by **JohnCKL** » 07 Nov 2003, 14:11

After a drive and shutting down my 1996 Xantia 1.9TD engine, I lifted up the bonnet and heard a slight hissing sound coming from around or between the engine oil filler and engine. After about 5 more seconds, it ceases. Is it any cause for concern?
Another problem is when I open the engine oil filler cap when the engine is running hot, the hot oil vapour shoots out worst than the exhaust! I guess my piston rings are worn. Is that a correct diagnosis? Thanks for your advise.

Kowalski · Post by **Kowalski** » 07 Nov 2003, 15:11

Check your breathers. If you get a blocked breather you can end up with a pressurised crank case, once the engine stops the pressure disapates (hissing) then the hissing stops because there is no more pressure to escape.
In any case the breathers should allow any blow past to escape without pressure building up in the crank case which seems to be happening on your car.
If the engine is easy to start and idles smoothly (i.e. all cylinders firing evenly) and pulls strongly then it's unlikely that you have any sort of blowing past problem.

Dave Burns · Post by **Dave Burns** » 07 Nov 2003, 15:18

Check the pressure release screw is tight on the hydraulic pressure regulator, if its slack there will be a hissing sound as the accumulator sphere discharges.
Dave

JohnCKL · Post by **JohnCKL** » 07 Nov 2003, 21:00

Thanks Kowalski, Dave. My engine is not so easy to start, half of the time, it cranks for 5 seconds without starting but will definitely start after the second crank. Idling is smooth, yes but pulling strongly, not sure, especially going uphill is not that strong. Will check on the breather and pressure release screw. Much obliged.

Richard Gallagher · Post by **Richard Gallagher** » 08 Nov 2003, 00:50

Is your Xantia a VSX? If so, the hissing noise you are hearing will almost certainly be coming from the hydractive valve situated just behind the radiator with a sphere attatched to it. It switches onto soft mode for a few seconds after a door is opened to stop the car jerking up/down.
However, if your car is not a VSX ignore the above!

JohnCKL · Post by **JohnCKL** » 08 Nov 2003, 12:19

Mine is a SX, not a VSX but thanks for the advise all the same.

mbunting · Post by **mbunting** » 08 Nov 2003, 12:58

Do you have Aircon ? Could be something to do with that..
A long shot, but check all the wiring in that area, the starter motor & solenoid is just below the area you're talking about, and mine burned itself out because of shorting wires not clipped in properly by a national clutch replacement chain. I didn't realise this until one morning it didn't start. ("Oh, that's what that funny noise last night must have been").
The sound you hear could also simply being the pressure ( which would worry me ) in the filler that you mention.

JohnCKL · Post by **JohnCKL** » 08 Nov 2003, 22:21

mbunting, I do have aircon cos staying in the tropics. Its a matter of survival to have aircon here or we'll be fried to bits, haha. Hmm, yes, gotta check out the wiring there too. It could very well be from the engine oil filler cos when I opened it when hot and running, the hot oil fumes just shot out and I'm sure the pressure build up is there. Worries me too, having so much fumes going through the vent breather into the air intake. No wonder I'm losing my engine oil, gotta top up every month or two. And kowalski, I don't think my car is pulling strongly, feels weak and underpower when accelerating. I gotta make a compression test to see what's the problems. Thanks again, guys.