skinters

Just polling opinion on this. Not sure if this is the right place (not a scooby)

Mr Kwik Fit overfilled my Mobil 1 by over 1 litre (more like 1.3) I checked just after this was done but to0 soon and it hadnt drained back (doh). Suggest you do not use Kwik Fit no matter how cheap their deal is....

Anyway - a month or so later, starting wasnt so good and I note oil on the spark plugs. Sob.

Oil probably gets up past piston rings due to extra pressure from below and my theory is it should be ok now.... No visible oil was coming out exhaust apart from a tiny puff on startup which I thought was unburnt fuel due to rough starting.

Drained off excess oil and changed plugs and have yet to go for a proper drive.

Do you think this has knackered anything?

scoobyster

I think it's bad news for the cat if you've been burning oil.

skinters

hmm - good point - cheers. Time will tell on that one although I'd rather replace the cat than need to do all the piston rings... which is my current worst case. The cat is a metallic one so in theory a little tougher than the standard cermic ones.

Shark Man

More likely the oil came out the breathers into the inlet tract rather than getting past the rings. Not really an issue, but some cars do have oil separators/PCV valves which can get clogged up when the oil residue starts to dry up and go sticky.

Also, depending on how the breather system is plumbed, oil can coat the the throttle plate and idle control valve, attracting dirt/dust and causing it to gum up.

Catalytic convertors are quite robust items considering how brittle and prone to melting they are if an engine is overfueling/misfiring. I've known of cars that guzzle over a litre of oil a month and still has no problem with MOT emissions - so obviously the cat is still doing its job.

In extreme cases excess oil causes foaming and aeration, causing air cavitation in the oil pump (affecting oil supply), and air pocket in the oil ways and bearings - air not being so good at preventing metal to metal contact than oil. So ultimately the worst case is bearing damage; but this is all theory as I have never seen it happen, or known anyone else who has actually seen or had it happen, so you'd have to be very very unlucky for it to happen to you.

skinters

Thanks Sharkman -
So - I finally got to take the car for 60 miles drive. Longer would have been better. New plugs stayed fresh clean (so far). I also did a compression test - 179, 179, 180, 187psi so fine for a 165k miles engine and I certainly havent blown anything obvious. PHEW. I can now get on with my turbo project...
PCV system looked very clean too so assume it must have been excess oil in the oil control rings on the pistons...

Net: Steer clear of KwikFit muppets. If you do use them, check and double check what they have done.

MattN

Never had a problem with them myself.

skinters

Fair enough - the quality of service varies from branch to branch and person to person so I shouldnt really tar the entire UK network with my experience

I think 'the boy' did this one...