Engine Performance problem
2004 Lexus RX 330 6 cyl All Wheel Drive Automatic 77000 miles
Milage is currently 77,000 kilometres which is approx 50,000 miles - so relatively low klms for this type of car being a 2004 model.
Just over a month ago noticed small White/grey puff of smoke from exhaust on start up - now it is a cloud.
Had it serviced 3 weeks ago and have had them look at it twice since then as situation is getting worse.
Have used 15 litres of oil in last 3 weeks doing approx 1200 kilometres. The mechanics initially did not know what was the issue as compression etc all is well in spec, they are suggesting that I need to have the piston rings looked at - this sounds expensive.
There are no oil leaks on the gound, no engine noise or tapping that would indicate worn engine.
I noticed a sludging in the oil resevoir about 25000 klms ago and did an engine flush to remove sludge - have since done regular oil changes (every 10,000 klms) and engine flush on each of these occasions.
Last week in desperation I put in a " stop smoke" product and still no relief.
Any suggestions on what might be wrong and is there a cost effective remedy?