Called my service advisor asking about oil change on the GSF if I can use synthetic oil change. He told me that the GSF oil changes are every 5k with conventional oil. I'll be using the Amsoil Signature oil which is 10k or 1year which ever comes first. would that void warranty? Is the GSF required every 5k or 6mothns which ever comes first?

 

My humble advice would be that you do not exceed 5,000 miles regardless of the ability of such good oil to not loose its lubrication properties in over 10,000 miles... It is mainly a matter of suspended ppm of various metals in function of the filters ability to remove them, or keep them below a certain level. In order to keep maximum performance (output under load) for a long time (since its a reliable Lexus), one would want to maintain these suspended "metals" under certain limits. Their calculation is that this would be achieved so long as you are flushing the engine of its oil every 5,000 miles. Also keep in mind that they know that maniacs like me are driving often at redline and/or at track and that will also warrant more "flushing' more often.

I use Amsoil Dominator 10W-30 Racing oil which is the highest level of protection that they make for that application. I also use their engine and transmission "flush" product right before draining so as to completely clean and flush "everything" that can be drained by gravity out of the engine. This will greatly help in preventing the buildup of deposits, sludge, etc. This product basically takes 15 minutes to degrade or lower the viscosity of the oil to be changed as much as possible to make it look like water (0W-0). When you open the plug it comes out with a vengeance, been caught off guard many times. Hope this helps.

 

 

I'd take a look at these before deciding to throw away $125 in oil.

https://www.clublexus.com/forums/gs-...-uoa-here.html

https://www.clublexus.com/forums/is-...-uoa-here.html

https://www.clublexus.com/forums/rc-...hetic-oil.html

Finally, here: https://540ratblog.wordpress.com/201...-test-ranking/

While RAT's testing is only film strength when new, your choice is at the top of the list for performance when new. Mobil 1 is very near this and less than half the cost. I am running factory OCI in the GS F and running Mobil 1 5w-30. You can see the wear metal results in the first thread I linked. While Amsoil performs better in lab testing for film strength, I would be very surprised if you saw a significant difference in wear number from what I am seeing with Mobil 1 on a street driven vehicle.

Also, you can see 12k and 14k mile results from Mobil 1 in my IS F in the second thread. The only oil I have run that disappointed me was the Mobil 1 EP recommended in the RC F thread.

I don't make oil decisions without data. Our engines hold enough oil to warrant testing, because you'll be buying 10 quarts for a complete oil change. At $12.95 a quart you're paying a large premium over Mobil 1 which is also in the INCREDIBLE category for film strength performance. As of this writing, here's what RAT has for 5w-30 as INCREDIBLE performers:

3. 5W30 Amsoil Signature Series
7. 5W30 Valvoline Full Synthetic High Mileage with MaxLife Technology
8. 5W30 Pentosin Pento Super Performance III
10. 5W30 MPT THIRTY-K
13. 5W30 Mobil 1, Advanced Full Synthetic, API SN, GM dexos 1 approved
18. 5W30 Mobil 1 ESP Formula (Emission System Protection)
19. 5W30 Quaker State Ultimate Durability, API SN, GM dexos 1 approved
20. 5W30 Pennzoil Euro “AV” European Formula
22. 5W30 Mag 1, FMX, European Formula, API S”M”, ACEA C3-08, synthetic
25. 5W30 LE (Lubrication Engineers) Monolec Tetra-Syn, API SN, GF-5, dexos 1
26. 5W30 Oil Extreme Motor Oil, API SM synthetic
28. 5W30 Valvoline MaxLife High Mileage, API SN, synthetic blend
34. 5W30 NAPA Full Synthetic, API SN, dexos 1 approved

As you can see, there are many solid choices for a lot less money.

 

 

You won't go wrong with any of the oils in the post you quoted. Decide what fits your budget because none of them will disappoint you for the intended purpose you stated. I run Mobil 1 simply because it is available at Wal-Mart almost anywhere in the country, and it fits my use model perfectly. The report from Blackstone on the GS F is outstanding, so I have no intention of changing something that is working especially when 10 quarts of Mobil 1 is less than $50 compared to Amsoil's $129.95 + tax + shipping.

 

how long have you been using mobile 1
can you post the blackstone labs report for us to see?
Im on the fence on which oil to use also i wanted to use amsoil but if u say the mobile one gives good blackstone results then i will be ok using it.

 

Both these threads have Blackstone results. I have used Mobil 1 in my IS F for most of its life and it's over 150k miles now. The GS F has been on Mobil 1 since 10k miles, it is on its third round of Mobil 1. You can see all the details in the reports I have posted.

https://www.clublexus.com/forums/gs-...-uoa-here.html

https://www.clublexus.com/forums/is-...-uoa-here.html

 

Also meant to respond to this one lubuxracer. Really good point on finding that reasonable happy medium regarding oil performance in function of cost. With the very expensive products one gets the feeling sometimes that there is a little of the "law of diminishing returns" involved. As you state, data indicates that much a "cheaper" oil, that is still really good, more than does the job for "the intended purpose" or the application that most people have; at less than half the cost.

My application sometimes feels wrong... hahaha. Will be doing some track days in July, in FL, at very high temperatures obviously. Because that is my application, if there is a small edge to be gained by the best lubricant that I can get, I then don't mind paying more for it.