2000 Rx 300 Oil Options

[sigtauenus]

I did a timing belt change a couple weeks ago on my wife's 2000 RX300 at 155,000 miles or so, and while I was in there did a valve cover change too. I found some varnish like that pictured below, pretty close to the same color, if it wasn't exact then maybe a bit lighter in color than pictured. There was a bit of sludge in the recesses of the head but nothing significant. I added half of a can of seafoam and am going to drop the oil pan to inspect the contents, change the gasket, and then add a new oil and filter.

The engine runs fine, and I can live with its current condition as-is, since it really doesn't look bad for having 155,000 miles on it. I have been using Valvoline Max Life dino oil 5W-30 for the past 30,000 miles (bought car used), but am considering switching to Mobile 1 full synthetic 5W-30 as I've heard it will help avoid the sludge better with the higher engine temps the RX runs with and perhaps even help to clean out some of the varnish on there now.

Also, I heard that with higher mileage engines it helps to increase the viscosity to say 10W-30 or 10W-40. I've never run anything besides what the manufacturer specifies. I live in Virginia Beach, so it does get cold in the winter here, so I'm hesitant to change the viscosity on the oil.

Opinions?

[Ericok]

It actually looks pretty clean. Penzoil Ultra is another alternative - but it's hard to find.

[Filehorse]

I switched to Mobil 1 10W-30 about the time the original warranty expired. I change it every 5,000 miles and have no concerns about engine lubrication. I went to the Mobil 1 synthetic in hopes of avoiding the dreaded Death by Sludge common to these engines. The 5W-30 was specified in an effort to improve fuel mileage ever so slightly. I personally use the 10W-30 and would certainly consider the 10W-40 for use in hot weather conditions. That said, using any version of Mobil 1 and changing it every 5,000 miles is probably enough lubrication overkill to avoid any concerns about oil viscosity in these engines.

[TomC]

The top end looks very clean - zero sludge. The only reason for 'high mileage' oil is to cut oil consumption or slow down seal leaks. Stick with what you are doing now, would be my recommendation.

Tom