Lil4X

Amsoil has made many claims for "extended interval" oils and filters in the past, but it would be interesting to see if they are really standing behind their warranty. If you are out of the T/L warranty period, you're on your own already - but if not, accepting these advertising claims could be pretty risky. The engine in your Lexus is a VERY expensive replacement item, unlike, say, a small-block crate motor. If you accept Amsoil's "warranty", be sure it is ironclad, brass bound, and copper-bottomed.

A few years ago we had a CL member who was an Amsoil MLM dealer brag about his 25K mile oil change interval on his RX 300. At about 26K miles, he ran every bearing in the engine - the oil pan having become essentially a gob of goo. Poor guy was out about $13K to replace the engine, and was hopping mad that Lexus would not honor his warranty. (Be careful about posting your brags about loooong oil change intervals)

Amsoil, his erstwhile "employer", would not even talk to him . . . saying his problem was with Lexus.

Moral: Read the Owners Manual - the terms of your warranty are spelled out in detail. Ignore them at your own risk. Don't expect Lexus to honor the advertising claims of a multi-level marketer.

TunedRX300

Syn vs Dino and change interval always spark a debate. I believe people are starting making it a personal issue rather than taking a step back and let an owner just research and do what he/she prefers. The key is to research because Lexus' owner's manual is not entirely accurate. e.g. if you believe Lexus' recommendation on RX's tranny of 60K change under "severe" driving condition (e.g. towing), you may just kiss your tranny good bye after powertrain warranty expires.
Engine oil is important, but how many people actually give the same amount of attention to brake fluid? I am not sure about you all but I rather have a failed engine over a failed brake, a marginal engine over a marginal brake. BTW, anyone even know how to change differential fluid? Heck, can any "engine oil expert" even tell me the difference between transfer case fluid and differential fluid on the AWD RX?

Lexmex

When the service manual was written...how did Lexus know that everything was going to run just like the book...they didn't.

Lifetime tranny fluid...hmmm.

Except for tranny fluid, coolant and anything to do with the differential, I change out my oil, brake, PSF several times a year. TunedRX300 is right that you should not overlook these things.

Synthetic vs. dino should have been a dead issue a long time ago.

The only issue I have ever seen crop up when switching from dino is sometimes there is some leaking at first and only with lighter weight oils. By the time the car is getting up in miles, it is probably time to think about a higher weight oil any way.

Now if you want to debate different brands of synthetic oils or even better what grade/weight of oil should be going into your RX...those are great discussions.

DaveJ

Thanks for all the replies on this thread. Apparantly it's not such a simple decision for me to switch to synthetic oil after 90K miles. Although I've cared for the car with oil changes every 3500 miles, I'm still concerned I could create a problem by switching at this late stage. I'll stick with dino oil for the RX.

For my '06 GS with less than 10K miles I may switch to synthetic for reasons of better engine protection than dino oil. Some have said that switching to synthetic saves money because it extends the oil change interval, which of course makes sense. But with new engines still under warranty I would not want to go beyond the oil change interval suggested by Lexus. If there were to ever be a sludge or hint of sludge related problem with the engine and my documention showed I was changing oil at 8-10K miles, I'm sure that would be reason for not honoring their engine warranty, even if it was synthetic oil.

So if I change to synthetic on the GS, I'll stay with the Lexus suggested oil change intervals, which of course makes my oil changes much more expensive but hopefully my engine is much happier.

xfirechief

U have made the correct desision as far I as am concerned. Leave the 90K vehicle with dino & put in AMSOIL in the new one. Amsoil does make a 7.5K oil if u do not want to go the 25K route.
I have since 1978 with NO ENGINE PROBLEM. AMSOIL DOES BACK UP ANY WARRANTY ISSUES if it proves to be the lubes problem. As of the last I have heard there has never been a oil breakdown problem with them if u followed the reqs. they have.

As for the RX 300 engine, Lexus admitted they had a engine problem as far as the oil jelling up in them. Check out any dealer for that problem. The RX 330 has not had any of this problem as far as I know.

xfirechief

AMSOIL was right doing that as it was a Lexus problem. As the moderator of this site u should be aware of that issue. Goo was a engine problem that Lexus warrantied. I beleive AMSOIL must have talked to him as they told him it was a Lexus problem. Dino oils have long been outdated and synthetics are taking over as the major provider for our vehicles needs. I would be surprised not to see synthetic oils in all engines from the factory within 5 - 10 years. Many hi powered engines are synthetic lubed from the factory now.

sha4000

iTrader: (1)

i dont drive an RX but i changed from dino to syn at 120k and have had no problems(knock on wood)

xfirechief

I have seen people switch to synthetic at 75K & not have any problem or at 25K and have big problems. If the engine has seen good service, that is 3 - 5 K oil changes there generally isn't a problem but say there is 25K & the oil or filter was never changed I might expect some problems.

Francis

I had regular oil for 80k miles. Then I used Mobil 1 after that. Now it has 100k miles on the clock. And I change oil every 5~6k miles. It runs fine still.

Francis 99' RX

knolex2001

Using BMW as an example: in switching to synthetics in the mid 90's, BMW had issues with new engines leaking because they still used engine seals designed for conventional oil. The thinner synthetics eventually passed through the seals and seeped out the engine. Initially, to fix this, they supplied BMW's from the factory with conventional oil until the seals aged (approx 5K to 10K miles), then switched to synthetics for their advertised 14K oil changes. They eventually developed metallic seals that could handle the thinner oil from the factory. Here is the problem with BMW's extended oil change program: Once the oil is changed, even synthetics at 14K to 15K miles, it looks like molassas. No BMW technician would do that to their own car. But BMW, in typical BMW behavior, lets their clients pay the price. If not now, then 80K-120K down the road.

NickO7

Mine had 178 Kmiles, and no leak after changing to M1 Synthetic.