[duke013]

Recently bought a 2009 MCS with 145k kilometres (90k miles) from the auctions. It has a noticeable whine from the engine especially when cold - noise reduces when warm. Diagnoses so far include isolating the water pump friction wheel drive to rule out the pump and removing the serpentine belt to rule out the ac unit, alternator and tensioner pulley. Whine still persists! Mechanics stethoscope indicates the whine is coming from inside the sump? Timing chain was on the way out so I replaced it. What are the symptoms of the oil pump chain or oil pump going bad - anyone had a noticeable whirr/whine when the engine is revved? If not oil pump/chain what else could be causing the noise?

 

[duke013]

Thanks Mike. Car is automatic so no thrust bearing issues. Whine exists in both Neutral and Drive. Stethoscope really points to the noise coming from inside the oil sump? Not many people seem to have had to swap the oil pump but it's possible it may have ingested debris from a previous cam chain guide failure or other catastrophe. Oil pressure seems good. Will drop the sump to investigate at the weekend so will spot any obvious wear in the chain and gears but not sure how to check for wear in the pump itself. May try and source a good used item and swap it in to eliminate it from my investigation. Will update this post for the benefit of the next guy who happens along this road....

 

[duke013]

Thanks Mike - latest update on this. After checking with the stethoscope all over the engine and transmission it was clear that the noise appeared to originate from the sump. I dropped the sump and found quite a bit of play in the oil pump drive chain. I've seen quite a few other people reporting similar issues but none of them advising that it was associated with a whine. Having removed the oil pump drive sprocket I was surprised to find it was quite difficult to turn the oil pump drive shaft. I was expecting to be able to turn the pump freely however there is significant resistance and it feels notchy to turn? Is this normal? Happy to swap in a new oil pump chain but reluctant to spend big $$$ on an oil pump until I am sure this is the root cause. Anyone had similar oil pump issues or any experience with the how freely the oil pump should rotate?

 

[duke013]

pump should be smooth fairly easy to turn have seen on some failures where run low on oil or dirty oil will hurt them, as for chains they tend to just about do 120k ie couple of timing chain changes, if were my car i would also stick a new timing chain on it at same time for piece of mind

Thanks again Mike and just to close out this thread for the next guy. Fitted a new oil pump and chain and problem solved - no more whining from the sump. Old pump had bits of a previous tensioner guide rail jammed inside the intake too - not enough to restrict flow but shows engine has had a failure in the past and may have run low on oil.