Extended OCI for 99 Avalon

[Mark_S]

I have a 99 Avalon, which has been a sludger for some. I have about 225,000 miles on the engine, which I bought new. I have religiously changed oil and filter every 5,000 miles since new. I am currently using Mobil 1 10W30 HM with either a Mobil 1 or PureOne filter. I had the valve covers off about 6 months ago, and there was no sludge, just some varnish discoloration.
After reading this forum for some time, I have decided to increase my OCI. I was considering 7,000 miles, but am now thinking maybe 10,000 miles. I don't doubt Mobil 1's abilities, just going the distance in my car and not forming sludge.
My question is this. Would you run 10,000 miles on a known sludger? If yes, would the Mobil 1 HM be sufficient, or would you go to the expense of Mobil 1 EP? Thanks in advance to those who respond.

Mark

 

[montero1]

Maybe you should get an oil analysis at your next oil change at 5k, to determine whether it not it would make it to 10k.

 

[Mark_S]

Will that tell me if it is sludging?

Mark

 

[Billy_D]

Keep the OCI around 5k. Your Avalon is not a candidate for extended OCI.

 

[IntegraVT]

I don't think I would be comfortable with an extended OCI on our 1MZ-FE, even with M1 EP. I think this engine is better served by more frequent changes with less expensive oils.

But you've definitely been doing something right if you've gotten ten years and 225k out of a notorious sludger.

 

[ChiTDI]

225k w/5k mile OCI in a known sludger. Congrats. I have one too and no thanks to extended intervals with this engine. If anything, I'd shorten the PCV change interval and keep the oil regimen you're using. After another 225k we can begin to second guess. Nice engine otherwise, no?

 

[Durango]

Mark_S,

If it were my engine I'd go no further than perhaps 6K on any synthetic oil and then ask the mechanic to engine flush the innerds annually. It's cheaper to change the oil more frequently than to risk any sort of engine failure due to sludging issues.

Durango

 

[slider]

10K MAXIMUM with a top grade synthetic on this engine if it's in good condition. My Sienna with 215K (same engine) has been getting 7.5 - 10K intervals with Redline and GC and no problems whatsoever.

I would do an analysis with TBN at 7.5K and see how much reserve TBN you have under your conditions before extending further. What happens with these engines is that the oil does fine up to certain point and then deteriorates very quickly. It's a fine line between okay and very bad.

In all cases, 5K intervals with synthetic is a just a waste of money in an engine in good shape.

 

[parimento1]

I just put M1 EP 5W30 in my 97 Avalon this week. It is the first time I am using a synthetic. I can tell you I definitely notice a difference in power, prob from less friction, also, the car does not lose speed as fast when coasting. I didn't think I'd notice anything, but I see that there is some credence to the synthetic advantage. I plan on going 7k miles with it, or just about double what I use the conventional for. Only reason why I switched for now was so I do not have to change the oil again until the weather gets warm again.