5W20 Or 5W30

[Santa29]

Hi, reading through posts and notice that there are discussions about 5w20 and 5w30, there was a TSB in 2006 to switch to 5w20 for some cars, but then the 2009 were produced later and the manual still saids to use 5w30. I have read other posts claiming certain dealers are putting either 5w30, 5w20, or even 10w30. Now I was wondering which is right and has Lexus actually came out and told us exaclty if the new oil should be 5w20 or 5w30, also how much does this really effect gas mileage, engine, etc? Any official word as I would like to change the oil myself and am now confused as to which I shoudl be using.

[lenore]

5-20 should be just fine....Most all of the new engines can use that....My RX400h runs great on it.

I Have even used 0-30 on my old RX300 (1999) and worked fantastic....Note I do use full synthetic....

[rx350guy]

Hi, reading through posts and notice that there are discussions about 5w20 and 5w30, there was a TSB in 2006 to switch to 5w20 for some cars, but then the 2009 were produced later and the manual still saids to use 5w30. I have read other posts claiming certain dealers are putting either 5w30, 5w20, or even 10w30. Now I was wondering which is right and has Lexus actually came out and told us exaclty if the new oil should be 5w20 or 5w30, also how much does this really effect gas mileage, engine, etc? Any official word as I would like to change the oil myself and am now confused as to which I shoudl be using.

Hmmmm.. My owner's manual recommends:

Toyota Genuine Motor Oil or equivalent

Oil grade: ILSAC multigrade engine oil

Recommended oil viscosity: SAE-5W-30

And I've never used anything else. The Toyota and Lexus dealerships where I have my vehicle serviced always use 5W-30 as well. I never knew there was any question about the correct viscosity to use..

[lemon]

Per this Toyota chart

http://us.lexusowner...showtopic=68152

you can run 5w20 or 0w20. Take your pick and don't stay up at night worrying. However, I wouldn't hesitate to run 5w30 in the vehicle if that floats your boat.

By the way, I'm using the Highlander HV recommendations for you 2008 RX400h. Mechanically, the vehicles are identical.

[mdrx350md]

It doesn't make a huge difference. My sister's 08 has 106,200 on it now. I put in Pennzoil High Mileage 10W-30 (March-October if I have it around), Pennzoil High Mileage 5W-30 (most of the time) and Motorcraft 5W-20 (if available, it's a Ford brand oil and one of the best values around). I like the HM due to the high mileage and in hope to keep the seals in check. I use all the oil for 6,000 miles and change out the OEM Toyota filter every other oil change. No difference in gas mileage and no more particulate by doing the filter every other change. I always overfill by 0.5 quart. I stopped using synthetic a year or so ago because I don't really use any benefits of it...extreme climates, tracking the car and long intervals. I rather change it out at 6K than go longer on synthetic...I ended up changing it at 9K anyway, so it's cheaper to use conventional aka dino oil. I've read all the UOAs etc and visit bobistheoil guy a few times a week and imho find synthetiic a waste for me. Just for reference I was a huge synthetic fan as I probably used up about 250 quarts (everything from Amsoil, Pennzoil Platinum, Castrol syn, Rotella T6 5W-40, Valvoline synthetic, Supertech synthetic) in the last 6 years or so in multiple cars and found no real benefit. Syn only came in handy when I was doing 10-12K oil changes on my sister's 04 Accord Coupe for about 120K then I went with the routine above. I sold it at 196K due to transmission issues as the engine was running like a champ with redlines every single day of its life. As for different weights...I use Mobil 15W-40 "diesel oil" in my 05 G35 coupe and see no mpg difference from various 5W-30 weights.

[lemon]

Hi, reading through posts and notice that there are discussions about 5w20 and 5w30, there was a TSB in 2006 to switch to 5w20 for some cars, but then the 2009 were produced later and the manual still saids to use 5w30. I have read other posts claiming certain dealers are putting either 5w30, 5w20, or even 10w30. Now I was wondering which is right and has Lexus actually came out and told us exaclty if the new oil should be 5w20 or 5w30, also how much does this really effect gas mileage, engine, etc? Any official word as I would like to change the oil myself and am now confused as to which I shoudl be using.

The TSB about the use of 5w20 was for the 3MZ-FE engine (the 3.3 V6 in the RX330/400h). The RX350 uses the 2GR-FE engine (the 3.5 V6) so that probably explains why the later model's manuals state 5w30. However, in 2010 models (which still use the 2GR-FE engine) Lexus specifies 0W20 oil only. Now, did Lexus spend all sorts of money retooling the engine building plant to make tighter tolerances in the engine so 0w20 could be used, or did they just do some (cheaper) research and discover that 0W20 would be fine in the 2010 without making any changes to the engine from 2008 and 2009? Or did they switch to 0w20 for some small improvement in fuel economy?

The same question could also be asked of 2005 RX330 owners who have the same engine as 2006 owners who can use 5w20 per the Lexus TSB.

In the end, it's your vehicle and your call. But I wouldn't hesitate to run 5w20 or 0w20 if it were me.

[Messerchmidt]

mobil1 5w30 here

[EyesofThunder]

I just switched to 5W20, no issues, mpg does seem improved over 5W30.

This was my reasoning,. the 1UZ-FE is tigher spec than the newer V8 engines, I feel it would be unwise to run thicker oil in the 1UZ-FE than 5W30 in any case (but I have heard of it and they claimed no issues), and if Lexus is spec'ing 0W20 in the new engines, that should be MORE than accecptable in the 1UZ-FE. Here are the clearances... :

1989-2006 1UZ-FE/3UZ-FE (4.0L and 4.3L V8)

Rod oil clearance: 0.0011" to 0.0021"

Main oil clearance: 0.0016" to 0.0023"

Ring Gap: 0.0118" to 0.013" (87.5mm/3.44" bore, 82.5 mm/3.25" stroke)

2007-up 1UR-FE/FSE

Rod oil clearance: 0.002" to 0.0024"

Main oil clearance: 0.0024-0.0027"

Ring Gap: 0.009" to 0.013" 94mm/3.70" bore, 83mm/3.26" stroke

[Lloydk47]

On 7/14/2011 at 9:46 AM, lenore said:

5-20 should be just fine....Most all of the new engines can use that....My RX400h runs great on it.

I Have even used 0-30 on my old RX300 (1999) and worked fantastic....Note I do use full synthetic....

I have used mobile one 5-30 full synthetic for over 10 years. First on my 1999 RX300 with 235,000 miles and now on my RX 350. change every 4,000 miles.

[Lloydk47]

This is from a dealership.

Best Answer:  I'm not sure what the car comes with from the factory, but at the dealership they use castrol syntec 5w30 synthetic blend. Its good for 5000 miles. The "Best oil" is really personal preference. Some people like to spend a lot on royal purple or Lucas racing, others swear that the cheap stuff is just as good. Its all up to you, but just make sure that there is always oil in the car and that you change it regularly and you will be just fine.

[RX400h]

I've been using 5W-30 for 14 years and 120,000+ miles now. At this mileage, I would not use 0W-20 oil but perhaps 5W-20 would be okay. I do add a container of Chevron Techron to the gas tank at every oil change (every 5000 miles).