Synthetic or regular oil ?
 

I read, on a bottle of synthetic oil, that it's better for cold start then common oil. I'm wandering if that would help the diesel sounds some are hearing during cold starts.
Any comments ?

I doubt it would help the diesel sound, based on what I have read on other sites that causes that sound upon start up.

However, I have been trying to figure out if switching to synthetic would be good and if so, at how many miles.

My thought would be a good quality dino would be fine in Arizona. If you want to go synthetic and extended OCIs do oil analysis to determine what’s proper for your driving habits. Also remember if you go to extended OCIs and have some type of mechanical engine failure your warranty could be denied if Lexus somehow determined the car was not maintained to the recommended OCI.

All that said I have run extended OCIs on all my vehicles to include my 240,000 mile 960 Volvo.

If I switched to synthetic I would not expand the interval between oil changes, I would only do it to provide better lubrication and reduce engine wear.

IMO I think anyone would be fine by following the recommended intervals, and using either quality dino or synthetic oils. Using dino, I've never had an engine problem due to improper or poor lubrication with either my personal or company cars (which tend to get driven a little harder and to higher mileage than the personal cars). It boils down to a personal choice and comfort level.

My original concern was whether a synthetic oil (changed at regular intervals) would help the diesel noise that seems to be manifested during cold starts and goes away after the engine warms up. The reason I bring this up is because the claim on the synthetic oil bottle mentions easier cold starts. Someone mentioned on a previous thread that Lexus claims that the noise is due to low pump PSI during cold start. If the PSI is low, doesn't it mean that the engine is not being properly lubricated during a cold start? Would the synthetic oil not take care of that, based on their claim of "better cold starts" ? Bottom line....will synthetic oil help reduce the diesel noise ?
oakplank

Yes, it should. The viscosity of synthetics is less effected by temperture than any quality dyno. "Low pump PSI during cold start" is probably due to the dyno oil being being more like 15w40 the 5w40 when its cold.

Synthetic oil will not reduce diesel noise. If you add 1/2 a bottle of Valvoline Synpower Oil Treatment aka VSOT, that should reduce the diesel type noise because it is loaded with Molybdenum which is a friction reducer but it also has lots of ZDDP which is essentially Zinc and Phosporus which are anti wear agents. Studies have shown that using high amounts of this can foul the catalytic converters but only if your car is burning oil, which seldom happens on a lexus. I have used VSOT in the past with wonderful results. It really quiets a car's engine.
As for the benefits of synthetic vs conventional motor oil, when they say it has superior cold cranking viscocity, that is true but we are talking about -30 degrees. Unless you live on the north pole, most places dont get that cold so there is no need for Synthetic oils. The only time there is a benefit of running a synthetic over conventional is when there is coolant or fuel diluting your oil. Conventional oils degrade(thicken) faster when there is a coolant or fuel mixing into the oil. Synthetics tend to have higher tolerances when it comes to shearing or thickening. This doesnt mean that synthetics never shear/thicken, just that it will take higher amounts of fuel/coolant leaking into the oil before it thickens or shears.
I personally use synthetics because I am not car savvy, and if there was coolant or fuel or dirt leaking into my oil, i would never know it, so if i am using synthetic i know my oil will have higher tolerances for these types of leaks and maybe protect my engine longer. Basically synthetics buys you more time than anything else.
The only TRUE synthetics in the market are 2 types. First is Polyalphaolefins(PAO) which is catagorized as Group IV(4) synthetics and examples of these oils are Castrol Syntec(Made in Germany) 0w30 and Amsoil. Second type of Synthetics are Polyolesters(POE) and they are Group V(5). The only one i know of is Redline.
If you are good at changing your oil every 5,000 miles, then buying synthetics are a waste of money. Any conventional oil will do a great job and also keep your engine clean. I also recommend doing a Auto-Rx treatment once your engine goes over 100,000 miles. Basically auto-rx is a additive that has a detergency effect and tends to clean your engine. If you take your valve covers off and see varnish/sludge, it would behoove you to do this treatment. If you want more info go to www.auto-rx.com.
Just a word of caution, if you have used conventional oil through out the life of your car, and switching to synthetic oil when the car gets older can cause leaks, this is not a fault of the synthetic oil but more so the synthetic oil cleaning your engine and exposing the seals. The quality of conventional oils have improved dramatically and the gap between the two have significantly reduced, thus modern conventional oils do a superb job at lubricating your engine, at the same time keeping it clean. Most people here wont be holding onto your cars for 200,000 miles so using synthetics would be a waste of money. Any good conventional oil meeting API SM rating would do the job admirably. Good conventional oils in my opinion are Castrol GTX, Pennzoil, Mobil and Havoline. Hope this helps

My Lexus dealer in here North Carolina uses "semi"-synthetic 10W-30W Quaker State for service. Lexus manual says only 5-30W is recommended.
Any thoughts?

Jaron5438

That's okay. Where the issue might occur is you have a W40 or a W50.

My original concern was whether a synthetic oil (changed at regular intervals) would help the diesel noise that seems to be manifested during cold starts and goes away after the engine warms up.

Since most Cold Engine Start Diesel like sound is reported by more people and service as coming from Fuel Injectors and I believe this to be true your idea will not work.
I have had this noise since purchase in May 06 and would give anything to stop noise.
My suggestion to Lexus is if all es350's don't make this noise then mine is broke and I want them to fix it even if it means changing the fuel injectors or whatever.
NYardich

Synthetic oil typically tends to run thinner than dino-oils of similar weight... I use synthetic injector oil exclusively in my snowmobiles, but hesitate doing so on 4-stroke "mild weather" on-road vehicles I own.

The weight of synthetic oil IMO will not help the clatter of the valves, etc. it may improve cold weather wear/tear from cold starts due to a film that more readily sticks onto engine parts internally, but I believe this film to be very thin... in other words it isn't going to close tolerances.

I've said this many times before... Most of the time these engines clatter when cold is due to "piston slap." Which depending upon design is perfectly normal, it should go away after 10 mins of driving... No matter what oil you use, this will not be prevented.

It would be OK to run a THICKER oil, but at the expense of more cold start wear and tear... The thicker oil would help eliminate the noises from the head, etc... But I imagine piston slap would be far more noticable.

It's all a trade off.

No. The specification for every Toyota engine that I can think-of off-hand is, "Greater than 3psi, 4.5psi, or 6psi." (Depending on the engine.)

Use a good synthetic, and the stock change intervals in warranty. Out of warranty forget the OEM interval. Flush the crankcase out, do an oil anylisis & find out how klong you can actually go on the oil/filter & save yourself the time & money of doing it.



And use the recommended oils for your temperature range, be it 5w-20, 5w-30, or 10w-30.

Nope. If anything, the diesel noise may tend to be slightly LOUDER if synthetic oil is used. Your ES350 owners manual says genuine Toyota 5W-20 (conventional dino) is the factory fill oil and recommends owners continue using this oil or the genuine Toyota 0W-20 grade (which is synthetic). The ES350 scheduled maintenance guide recommends changing the oil at least every 6 months or 5,000 miles even if synthetic is used.

Since 2003, numerous owners of the GR series V6's have reported diesel engine noises when the engine is cold yet not one has experienced engine failure or other problems. Therefore, I think it's safe to assume the noise is normal, especially considering several of Toyotas most famously durable motors (22R series, 3A & 4A series) made alot of clickety-clackety racket when cold yet it was never found to be harmful.

OK for clickety clackety noise for Toyota but for a Lexus? Just proves some peoples comments to us that the Lexus ES350 is just a Camry. I go on that if they drive the ES350 and then a Camry, there is a difference (except for the clickety clackety noise which they share).
In reading and writing about the clickety and clackety noise, it just reminds me of the Cluck You chicken franchise. Sorry, but I'm LOL.......

It would be funnier if I didn't have the noise though.