Is Rod Knock the Likely DIagnosis?

[u05je7]

2006 Impreza STI PPP with 54K

Driven very gently for the latest journey. In general not driven hard at all.

Oil pressure light flickered on. About two miles from the nearest safe place to stop. Noted that on slight downhill/braking it was possible to get the light off. Also have check engine light now. On the dipstick the oil level is fine near the full marking.

Added an extra litre of oil to the car and this seemed to sort the oil pressure light. Unfortunately it is making a sort of knocking sound intermittently. Hard to describe but this is the best I can provide from searching youtube:

www.youtube.com/watch?v=sik-OddhWzo

To me it doesn't sound constant. It will just occasionally be present.

Very gently nursed it home. It was driving fine and the engine seemed smooth in its output. Stopped for some petrol, restarted and the check engine light is now off. Oil pressure off for the duration of the journey. Knock sort of sounds decreasing with time.

I had thought that it had magically sorted itself but got another knocking/tapping sound whilst coming off a roundabout on a sweeping left. Pulled onto drive (rolled onto slight incline) and the pressure light flickered on then off.

Thoughts? I presume Rod knock secondary to oil starvation. I'm curious to what caused the starvation. The oil levels were fine via the dipstick (parked on the flat) but it cannot be ignored that adding a litre cured the light. If the pump was gone why would the addition sort this?

Ultimately I suspect that I will require a rebuild.

Your collective thoughts would be appreciated

Thanks

[AndySpecD]

Could be an oil pick up pipe failure. They crack and then suck in air as the oil level in the sump drops. Adding the extra oil would have helped by raising the level but obviously isn't a fix. The knocking sounds like it may have done some damage by running without oil pressure.

http://www.iwsti.com/forums/video-collection/12339...

[AndySpecD]

Just to add that I had this after I had a Cosworth baffled plate fitted and they must have disturbed it. It can be fixed with the engine in situ (some say it isn't), although the engine needs to be released from it's mounts and raised slightly to get the sump off.

[u05je7]

Thanks for replying. I've had a brief chat to API and Scoobyclinic about it. Scoobyclinic did a very good impression down the phone of the noise the engine would be making. API also mentioned a pick up failure.

Debating whether to take the engine out and then pallet it to one of the two for analysis

[ScoobieWRX]

Just take the car to API and they'll whip the engine out, strip it and report back. Then once you know what's what you'll have a good idea of cost and repair time.

It may be you want to save some money by taking it out yourself but that might be nearly as expensive in the end when it's taken your time and inconvenienced you and there's pallet and shipping costs. You still have to pay for all that.