I have been using Auto-RX for a few years now and I have a concern. I have spoken to you previously about how I was not consuming oil in my 2005 Toyota Highlander but after using Auto-RX I now do. Currently I have a sludge application in the engine and just changed the filter out half way through the cycle and I am monitoring the oil consumption. I was about 1/4 qt. low.
Well I decided to try a normal application on my 2008 Honda Accord 4 cyl with 50k miles on it. I changed the oil with Castrol GTX and one bottle of Auto-RX. At 1250 miles (last night) I changed the filter per instruction. I checked the oil level and it was down 1 qt. I was shocked that I was a quart low. Previously there was no oil loss to my knowledge.
Is this "normal". I am very concerned since it seems like this is happening now on a second car after using Auto-RX.
With respect to the Highlander, although not common sometimes in motors with heavy top end deposits it takes time to dissolve because these areas are only splash fed for the most part. Until valve guides and seals are cleaned up completely there may be some slight oil burning from oil slipping past the valve stem seals. In a heavily sludged motor sometimes sludge is actually producing the sealing between the seal and the valve guide. This will self correct as the seal and guide are cleaned 360 degrees around the seal areas. Other possibilities are that the rings havent completely been freed up if they were stuck together with deposits. Although ring packs clean up quickly due to the amount of heat and pressure that is present in this area of the motor. Normally stuck rings will free up in roughly 500 to 750 miles of operation during the cleaning phase of the application. Last possibility is the PCV valve might be sticking, thus trapping excessive crankcase pressure. This can force oil past stem seals or oil control rings. I would be very surprised if this consumption continues after finishing your application.
With respect to the Honda, I would consider this to be unusual. Unless of course when filling the oil and adding the Auto-Rx you checked the oil level before firing up the motor to fill the filter. This would account for about half of the lost volume. Normally you would not need to change out the filter in a basic application on a motor which has only 50K on the clock, with decent maintenance history. I assume that your Honda motor has the V-Tec system of variable timing. This system is pretty fussy about running the proper weight and viscosity indexed oil. Most call for a 5W20 oil for the correct oil pressure and flow to operate the V-Tec properly. Many folks that have run even a 5W30 have commented on some oil burning. That little bit of added viscosity creates a situation whereby the advance or retard of valve timing is not as crisp and can cause some oil consumption. Be sure to run the correct oil spec in the conventional flavor during the rinse phase. I also think that this issue will pass. Rich
