2000 Sienna PCV / Oil Leak / Check Engine Light

You spin an interesting tale, but to no avail. There is nothing to do until you pull the code that turned the check engine light on. Lots of places will pull the codes for free, and for the price of paying the dealer to do it once, and at most twice, you can buy your own code reader and pull codes anytime you want and as often as you want for whomever you want.

You throw good money after bad by changing the oil far too often -- you buy expensive oil that is designed for long life, and then change it as if it is the crap that they put in Grandpa's engine in the decades that followed the invention of the wheel.

You drive a car that is closing in on 15 years old, and are asking why it leaks. Age, my friend. Age. The leak and the light are not likely related, and the oil you use and the light are not related. You are taking steps to fix stuff, but you don't know what to fix.

I doubt the Wal*Mart oil is a factor. Most likely you eninge is suffering from excessive blow-by, likely related to worng rings. The appearance of oil leaks and the coating on the PCV valve point to this BUT, it is only a guess. Next time the light is on, take your car to the local AutoZone and get them to read the codes for you. Regardless of the codes, a plugged PCV valve can contribute to oil leaks by allowing pressure to build up inside the crankcase and valve cover.

Ed

Jeff and Ed,

Thanks for your thoughtful replies. I really appreciate that knowledgeable individuals are still taking the time to participate and help others in this forum. A few years ago, at least 90% of the posts here actually had to do with Toyota ownership and maintenance, while fewer than 10% of the posts were by trolls, political zealots, and the lunatic fringe. Unfortunately, that 90/10 ratio now seems to have reversed to 10/90. It is the price and the blessing of living in a free society.

I agree that an OBD reader might be a good investment at some point. Ironically, this Sienna is the first vehicle I've ever owned (in more than 32 years of car ownership and maintenance) where I've had to deal with a check engine light. I get the idea that, even if I'm able to pull the code(s), there sometimes can be quite a bit of additional diagnosis and intuition involved.

So far, each of the CEL incidents has coincided with (if not been caused directly by) a clogged pcv valve. Each time that I cleaned or replaced the valve, the CEL turned off after a few driving cycles. So, even without the benefit of an OBD reader, I think I had reasonable intuition about the condition of the pcv valve (after I saw all the oil seepage from the engine).

I guess I shouldn't be surprised to be seeing increased blow-by after

153,000 miles. The strange thing is that I haven't seen any evidence that the van is burning oil. Since there hasn't been much time/ mileage since the last oil change (to the Mobil 1 High Mileage), it may take a while for me to see whether this oil actually reduces the blow-by, reduces the oil seepage, and allows the pcv valve to stay unclogged. I have to believe that different oils have different properties, and that some would be better than others at reducing blow- by (without simply switching to a higher weight oil). I will post again after I've had a chance to see whether there's been any improvement.

Finally, as for the short oil change intervals with synthetic oil, this was a conscious (if not very economical) decision, based on two factors: (1) 5-quart jugs of the Mobil 1 are relatively inexpensive at Walmart. (2) Normally I would run the Mobil 1 for an oil change interval of at least 5000 miles (as I do in another car that I own), but am deliberately committing "overkill" here since the Sienna's engine seems very sensitive to sludge formation.

I'll post again after I see how the van is doing over the next 1000 miles or so. If the CEL comes on again, I'll definitely buy an OBD reader and will report back with the code(s).

Thanks again for sharing your expertise.

Ron

Jeff, Ed and NM5K,

I just wanted to report back. After about four months and 3000 miles, the = Mobil 1 High Mileage oil seems to be improving the situation. The total oi= l loss during the last 3000 miles (with total mileage on the van now over 1=

56,000 miles) has been less than a half-pint -- i.e., next to nothing. I a= lso am seeing less evidence of seepage: There are only a few drops of oil o= n the garage floor after 3000 miles (much less than I was seeing before), a= nd I don't smell nearly as much oil burning (caused by dripping onto the ex= haust manifold). The check engine light also has not come back on. I did = notice that the pcv valve was a little gunked up. Although it still rattle= d somewhat, it definitely did not rattle completely freely, and there was a= coating of oil on the discharge end of the pcv. So I cleaned it with carb= spray. It now rattles freely again. I realize this may be a bandaid appr= oach (i.e., using the "high mileage" version of Mobil 1 and cleaning the pc= v valve every 3000 miles) to reduce seepage and keep the pcv valve clean, b= ut I'm hoping that it will continue to minimize the problems until I can ha= ve everything taken apart at 180,000 miles.

If the check engine light comes back on, I will pick up an OBD reader and l= et you know what I see.

Thanks again.

Ron