I have a 98 GS 400. What kind of oil is recommedned for Lexus GS 400. I know that 5W30 is best suited but do you know if Lexus recommends synthetic oils? What does Lexus use when they do an oil change? What do you think of KNN oil filters? What kind of oil filter do you recommend...I read in this forum that people are using Toyota oil filters of the Supra on their GS 400's. Which year of Supra oil filters are they using.

 

aaaaaaaaaaaaaaaaaaaaa

Mobil One synthetic or Royal Purple synthetic 5/30 is fine. Who cares what the dealership puts in the car, put the best in. Go to K&N's web page and read the benifits over the reg. filter. Then go out and buy a filter chip combo like a SRT. (you can do a search in club lexus and find way too many write-ups on the subject). Good Luck!

 

I've read somewhere that for normal driving, synthetic oil doesn't really make a difference. The main things to make sure:
1. Oil is SAE certified.
2. Never mix different viscosity oils in the same oil change.
3. Don't overfill.

Synthetic, as far as I know is much better for modded engines that run hotter and for engines with are run harder (raced), because it breaks down at much higher temperatures than conventional oils. For normal driving, I doubt you would realize any of synthetic's benefits.

If anyone has any verifiable info to the contrary, please share.

 

I don't have any solid proof, however I stand behind full synthetic oil based on experiece. I have always used full syn in my BMW's, SC and now GS4 and have had fantastic performing vehicles with little to no maint. issues.

Knock on wood...

 

In addition to my engine, I use synthetic products in my transmission and rear differential.

The shifts were noticeably smoother and believe it or not I could sense the car rolled smoother , as if the rolling resistance was less.

I'm typically analytical in my responses, but all I can say here is my buTT could tell the difference.

This alone was worth the change for me, whether or not the other claimed advantages are real or not.

 

once u go synthetic, you should not go back. bad, bad, bad...a big no no! not good for the engine.

 

And why would that be?

 

is it ok to switch to synthetic from dino oil after 140k?

 

You can switch back and forth from synthetic to regular oil. I am a firm believer in Castrol. I have tried synthetic, synthetic blend and regular oil in the GS, I have noticed no difference. IMO, the car idled rougher with they syntec. The syntec molecules do a better job of bonding in the cold and stay cooler in the heat. Though you have to push the hell outta your car to benefit.

 

If you plan on getting 200,000 miles out of you car, I would personally go with a synthetic... I use Mobil 1 with the stock Toyota oil filter if it matters any. I used regular oil for the first 10,000-15,000 miles of my car so everything could be well lubricated before I made the switch over to the synthetic oil...62,000 miles...no problems...idles like a dream

 

BTW...I push my car HARD!!!

 

Mike,

200,000 miles on the SC 400 and 195,000 on the ES 300 with no engine problems. Like I said I am a FIRM believer in Castrol oil. Though I do think Synthtic does not hurt, I don't think the addtional cost is worth it..

I change the oil too

 

This argument at the track goes back and forth like Chevy vs Ford. Its usually the old fashioned "Big Dog" dragster types that stick with conventional oil, and they're the ones who would benefit most from synthetic!

Facts about synthetic:

1. Does not use fossil fuels
2. Isn't refined from impurities
3. Lasts longer anyway, especially in high heat/high compression applications

My opinions on synthetic
1. If some of the best manufacturers are switching over to synthetic only for their ENTIRE line (BMW, Volkswagen, Mercedes, Aston Martin. not just the high models) there's probably a reason
2. Some manufacturers have been able to refine fossil fuels to the same standards as synthetic, and are allowed by SAE to market it as synthetic so beware
3. Blends offer no advantage, they still suffer from the characteristics of fossil fuels.
4. I've been using synthetic oil since my 96 Grand Cherokee (which was eventually traded in for the 98GS, which started the addiction.)

 

And if some of the most reliable engine manufacturers (Toyota, Honda) still use conventional for their entire line, there's probably a reason they haven't found the need to switch to synthetic.

My friend has 200K+ miles on his '90 LS, which had it's oil changed every 7500 miles with Valvoline conventional. Still runs great. As they say, Toyota engines seem to last forever. You'll have problems with the rest of your car far before you have problems with the engine (ruling out negligence).
The main person who will benefit from a 100K+ mile car that used synthetic is the person buying the car from you after you turn to a newer model Lexus. I'm sure they don't mind you spending the extra $$$ for them.

What makes Castrol oil any better than Valvoline, Mobil, Chevron, etc.? I think mainly the marketing.

If you substitute "full synthetic" with "conventional" in the quote above, that's been my experience as far as Toyota engines are concerned. I'm not about to try conventional in an European car that specifies synthetic.

That's the last place I'd go if I wanted to find out the real deal on a product.

No, Lexus does not recommend synthetic oils. They don't advise against using it either, except to say that you shouldn't extend your oil change intervals if you decide to switch to synthetic.

I think you got things a little mixed up. It's a Supra owner(s) that compared the domestic-made Toyota filter to the Japanese-made Toyota/Denso 90915-20004 filter, and decided the latter was the better choice. The 90915-20004 comes stock on Lexus 8 cylinder engines. The 90915-20003 is the same thing except a little shorter, and comes stock on Lexus 6 cylinder engines. I see no point in using the 03 with the 04 around, unless you're trying to save a buck or two.
Read up and get sucked in by more marketing!:
http://www.nbt-brunei.com/part/knowledge/oil_filter/

 

This is from the FAQ at www.lexus.com :

"Synthetic oil can be used at the first scheduled oil change. Please note that the use of synthetic oil does not extend the recommended oil change intervals. Please refer to the Lexus Owner's Manual Supplement for further information regarding the proper maintenance schedule for your specific vehicle.
If synthetic oil is used after that time, it should be the same SAE (Society of Automotive Engineers) weight specification and meet or exceed the API (American Petroleum Institute) grade specifications listed in the Owner's Manual. Even if synthetic oil is used, we do not recommend longer oil change intervals. Once synthetic oil is used, it is best not to switch back to petroleum-based oil."

I only use synthetics for the RX and GS and change oil every 5,000 like the manuals say.

With my van, it now has 297,117 miles. I have used only dinosaur oil but changed the oil every 3,000 miles. I buy any oil that's on sale but revolves around Pennzoil, Castrol, Mobil, Chevron, Texaco, PepBoys - but mostly the first three. I have only used Fram and Toyota filters. I have had bad luck with Purolators before. Incidentally, the van is draining oil now as we speak, and this fill will take me to 300,000 miles. I drain the oil for a minimum of 12 hours and depending on time, up to 2 days. I get an extra 1/4 quart of dirty oil that way.