I purchased a used Sienna van in July with over 200,000 miles on it. I immediately changed to a 5w-30 Pennzoil Ultra Platinum synthetic for several short OCI to start cleaning out any sludge in the 1MZFE motor. Went from a drop on the ground maybe once a week to several drops a day on the ground using the Pennzoil, so it appears the short OCI and high grade oil flushed something away from the seals that were already capable of leaking when not coated in gunk. First oil change was very dark after 1,000 miles.
On the front of the engine is a long washer/plate that spans two bolts over the exhaust pipe under the valve cover and above the oil filter. It creates a bit of a cupped area where liquids can gather. It was full of pooled oil and clearly leaking onto the exhaust and burning. I could even see the oil sheen from the valve cover gasket downward. I don't like leaking oil, and the rear valve cover gasket is a bear to replace, so I went with a high mileage Pennzoil syn blend 5w-30.
Now, what's strange is that my driving route to and from work is exactly the same. Same oil filter type, etc. After a couple hundred miles, there is no longer any visible sheen of oil leaking from the front valve cover gasket, and the area where it pooled up before at the exhaust is going away and now only about 1/2 as pooled up as it was before the high mileage oil.
Would changing oils make such a quick change? Would it be more likely that I am using a synth blend now instead of full synth? Or is the high mileage additives the more likely culprit?
I'm sort of new to geeking out on engine oils, so pardon if I may be seeing things incorrectly. From my research online, it seems like most people only saw an improvement in oil leakage after several OCI when switching to HMO.
On the front of the engine is a long washer/plate that spans two bolts over the exhaust pipe under the valve cover and above the oil filter. It creates a bit of a cupped area where liquids can gather. It was full of pooled oil and clearly leaking onto the exhaust and burning. I could even see the oil sheen from the valve cover gasket downward. I don't like leaking oil, and the rear valve cover gasket is a bear to replace, so I went with a high mileage Pennzoil syn blend 5w-30.
Now, what's strange is that my driving route to and from work is exactly the same. Same oil filter type, etc. After a couple hundred miles, there is no longer any visible sheen of oil leaking from the front valve cover gasket, and the area where it pooled up before at the exhaust is going away and now only about 1/2 as pooled up as it was before the high mileage oil.
Would changing oils make such a quick change? Would it be more likely that I am using a synth blend now instead of full synth? Or is the high mileage additives the more likely culprit?
I'm sort of new to geeking out on engine oils, so pardon if I may be seeing things incorrectly. From my research online, it seems like most people only saw an improvement in oil leakage after several OCI when switching to HMO.