dshahs420

After seeing extensive Used Oil Analysis on 5w20 and 0w20 oils, I am going to start using 0w20 since the results are spectacular with very low wear numbers unlike 5w30's which show slightly more wear. Shoot i have seen a UOA on a plow truck using 0w20 and it was eye popping good!!!!! 5w20 oils are what 5w30 oils were in the late 80's into the 90's.

Deven

TunedRX300

Got my Mobil 1 5w20 UOA on my 2000 RX300 and post here FYI
Please do not used it to fuel oil (dino vs. syn, thick vs thin, Amsoil vs Mobil) and filter (paper vs cotton) debates. That will lead to thread closed 100% of the time

8247 miles on oil, Fram XG oil filter until 6900 miles then replaced by Bosch Premium w/ 1 quart makeup oil, K&N air filter, mixed driving.

Lab: Oil Analyzer

Aluminum 4
Chromium 0
Iron 14
Copper 4
Lead 3
Tin 0
Molybdenum 97
Ni/Ti/K 0
Boron 58
Silicon 35
Sodium 6
Calcium 2324
Magnesium 26
Phosphorus 735
Zinc 1099
Barium 0

TBN: 2.17
Viscosity @100 C: 8.83
Fuel < 1%
Water 0
Coolant 0

Compare apple to apple with another 2000 RX300 with similiar setup (K&N filter) but used 5w30 and far fewer miles (5000).

http://theoildrop.server101.com/cgi/...c;f=3;t=001163

I am happy with Cu, Al, and Pb, lower or equal to the other RX300 with 5w30 linked above, more impressive considering I put on ~65% more miles on the oil.
Iron is low but would be perfect if it was lower, pro-rate it by dividing by 165% and compare to 5w30's 10 ppm -> pretty good for 5w20. Viscosity is right on the spot of Mobil 5w20 spec.
My opinion is silicon is high but not sure it is abrasive dirt to cause iron wear. I will need another test with OEM paper filter to see what is going on.
I am happy with M1 5w20, seems to do better than 5w30 for my driving style.
Take this report and interpretate the way you like and make your own decision.

Pheonix

I'm still running 5w-20 mobil 1 synthetic & still like it better.

dshahs420

overall a great report. Not too thrilled about the iron but its not bad for the miles you put on. Your silicone is high at 35ppm, there is definately dirt getting in so might wanna check your air filter.

BennySC400

ok, i'll be honest... i don't know the first thing about what all those numbers mean on a UOA. if anyone here (mainly TunedRX300 or dshahs420) has the patience to explain it, i would love to understand... maybe get a UOA done on my SC400.

but can you guys please answer me this: from what i understood from this thread, toyota/lexus put out a statement saying the new cars will start using 5W20 oil, and some will use 0W20. but that doesnt mean i can start using 5W20 in my 14-year-old SC400?

TunedRX300

You can use Oil Analyzer's Guide to make the UOA "speak" to you.
http://www.oaitesting.com/g2047.pdf
In short, UOA is just like a urine/stool sample one takes a during physical examination. Lab analysis result gives one insight on what is going on with the system - human body or engine in our case.
For starter, you can concentrate on TBN, wear particles, viscosity, and coolant leak to the engine.
Color of the engine oil is a very crude method, for example, Royal Purple has purple dye instead of honey color dye. If one uses how black the engine oil looks to determine effectiveness, then VIRGIN Royal Purple oil must be close to spent since its color is already close to black.

dshahs420

Yes you can use 5w20 oil with confidence, just check your oil level when you first use it just to make sure your car is not leaking oil. Older cars can leak with thinner oil. What grade are you using now?

As for the UOA and what the numbers mean check this link out.

http://bobistheoilguy.com/whatisoilanalysis.htm

JCtx

Thinner oil than the car was designed for is never advisable, as metal to metal contact can occur. Thicker oil is permissible if within the temperature ranges specified in the manual.

koolaidman

am i reading this correctly

it says gr uz jz seriese

that means

rx350 rx330 is250 is350 es350 is300 gs300(gen 2 and 3) lx470 gx470 and rx300 all can use the 5w20. hmmm i dunno about the lx or gx but who am i to agrue with toyota

TunedRX300

If metal to metal contact causes abrasive wears, metal particles should show up more in spetro analysis in 20 weight oil. However, the data shown here indicates otherwise - it is 30 weight oil that has more iron, copper, and lead particles for a given # of miles with similiar driving style.
Remember better oil flow lubricates and cool the engine, the question is which oil flows better, assume both have similiar chemical property?

BennySC400

wow... this sure is some technical stuff!

first of all, in regards to koolaidman's comment... isn't my SC400 engine also a uz-series engine? which means toyota says its ok for me to put 5W20 oil in it?

second of all, to answer dshahs420: i'm currently running 5W40 in it. for a long time my dad was putting castrol 5W50 in it. why? i have NO clue. i think he just bought the cases at costco and didn't bother paying any attention to the viscosity. so, i took over on this oil change, and i put in LubroMoly 5W40. i figured i'd go with it, cuz i know its a good true synthetic oil, and i dont wanna hop down to a 5W30 after the engine had 5W50 in it for so long.

my planned course of action is this: drive on the 5W40 oil for about 2,500 KM (approx. 1550 miles). then do an engine flush, and change to 5W30 Mobil1.

but perhaps you guys are suggesting i go right to 5W20. should i do a UOA on my current oil before i switch, so i can do one to compare?

and do you suggest doing the engine flush, as i mentioned, or do you recommend staying away from that?

for the record, my SC400 has about 127,000 KM on it (approx 79,000 miles)

koolaidman

i belive its a 1uz-fe that what u got

and i check toyotas quick tsb. and i could not find this tsb. going to get the tsb number and try again. but then again tsb's for toyota havent been updated in 2 weeks eg018-06

BennySC400

whats a TSB?

and can someone confirm or deny my planned course of action as being correct? thanks.

BennySC400

ok, i just figured out TSB means technical service bulletin

TunedRX300

I am not aware any glaring issue going straight to 5w20. One remote possibility is you have been using oil thicker than Lexus' owner manual's recommendation for a long time, you may have a false seal (seal not leaking because of thicker oil or sludge deposit).
You can use this dino UOA a SC400 owner posted using 5w30
http://theoildrop.server101.com/cgi/...c;f=3;t=000373
I would save the 5w30 UOA $ and buy Auto-RX to clean the engine, given you want to flush the engine anyway. Auto RX is an ester based cleaner to remove any potential deposit/sludge. Then go to 5w20 after the treatment and do a UOA to compare to the 5w30 baseline UOA.
Of course if you have $ to spend, go ahead and do before and after UOAs, which gives better comparasion.