Originally Posted By: ericthepig
Kevin,
I have a '98 Sienna (1MZ-FE). I bought it in 2001 w/ 62k miles on it. It now has close to 160k. Mainly shuttling the kids. For the majority of it I've done ~8k OCIs using Mobil1 (10w30, 0w30 and 5w30). A Toyota mech was in it at around 142k for valve cover gaskets and timing belt - said the engine was clean.
I heard about he sludge issue soon after getting the van. Did a lot of web research those first couple of years. The majority of vans seemed to be sludging in under 50k, and the '99 and '00 seemed to the the worse - some sludging in 20-25k - the earliest I saw was 14k. I've only seen a couple of post of Sienna's sludging after 50k. So, it seems to me if you have a sludger, you likely would have already sludged. There are a bazillion '98-'02 Sienna's that haven't sludged - many owned by folks that don't know about the issue, and forget to chg their dino for way too long. Just look at the numbers (from what I've read) - you had that surge of vans sludging that first couple of years, and now you don't hear much about it - even though these vans are getting old and high mileage.
And some of the sludge stories - there were numerous folks that claimed 3k OCIs (supposedly provided Toyota w/ receipts, etc), there was one guy that claimed doing 6k OCIs with M1 - and they sludged. So it seems if a person owned one of the sludgers, they were doomed almost regardless of the oil or OCI. (?)
What I take away from all this - these engines may be tough on oil, but something kinked on the production line (or from some supplier) that broke the camels back in a small percent. And if you haven't sludged by 90k, you're out of the woods (imo). Proceed with caution (but I think you could relax the 3k).
(Once again - my Sienna is clean and I've gone as far as 9k+ on M1)
Kevin, pretty good info above. The other thing with this engine is to keep the PCV valve and hose really clean.
I limit my OCI to 5k (w/GC) because of short trips and cold temps. 115k so far so good. Your plan sounds good.
BTW- Use OEM PCVs for the best results. IMHO