Hi,

Before moving to the topic of this thread (ie. oil analysis), I'd like to mention that there are several good threads about which oil to use and standard oils vs synthetics here at clublexus, such as:
Oil change interval question
and
What type of oil do you use? (The Mother thread) (Wow, that thread goes back to 2002! It really is the Mother thread!)

My topic here is about oil analysis, and not which oil to use, so I thought it might be better to start a new thread, rather than add another post to those "which oil to use" discussions. Please advise if I should move my new thread here to an existing one. Moving on . . .

I recently switched my 2000 RX300 from conventional Castrol GTX 5w30 to:
Mobile 1 Extended Performance 5w30 15,000 Mile Advanced Full Synthetic (Btw, there is a "high mileage > 75k miles version of this also available). I paired that with a FRAM XG3600 Ultra Synthetic 20k filter.

Today I was looking at my maintenance spread sheet, and was wondering what mileage to set for the next oil change. I found the following 2014 article on this topic and I thought it might be of general interest:
Should you change your oil every 15,000 miles? Here's how to decide.
That told educated me about DIY oil analysis kits and oil analysis services. So I research a bit and find this one:
Is Oil Analysis Worthwhile? - Toyota Parts Blog

I'm wondering if anyone who's using these extended mileage (ie. 15,000 miles+) "petroleum based synthetics" or actual 100% "synthetic synthetics" has ever done either a DIY or service based analysis? Btw, if you need to brush up on that topic see (e.g.) How Synthetic is your "Synthetic" Oil? and Motul – Tthe difference between 100% and full synthetic oil .

I look forward to your thoughts and comments of your experience with oil analysis of extended mileage "synthetics".

Regards . . .

 

This is car dependent on OCI so there will be variables for operating conditions encountered. I did a work-up over the years from 5-15K miles. As the car ages you'll be adjusting based on the analysis findings. The technicians at the lab will be able to advise based on those results. Mobil 1 regular here and ours has 215K.

 

Not sure if this matters or is even appropriate, but I've used Mobil 1 EP 5-30 in my 2003 Hyundai Santa Fe(2.7) since it hit 79k miles. It now has 186k miles. I took the oil pan off a few years ago and it was really clean. I do annual oil changes on that car and bumped up to 15k several times. Maybe averaged 12k for many years. I've never had any engine problems, but I never did any oil analysis- so not sure if this would help you. I started out that car from new with regular Mobil 1 synthetic.

 

I never go past 7500 and most are changed at 5k will Mobile 1 AP or ESP, I would rather not have acid going at the seals and oil is cheap and easy

 

Thanks to everyone who's replied! Your posts were all helpful : )

I only drive the RX300 about 3k miles/yr and it's at ~50k now. I'm thinking that 1) that engine will out live me (haha), and 2) I'll have the oil tested at the 2 year mark. For me, the whole idea of switching to the extended synthetic oil & extended filter was so to minimize the frequency of oil changes I have to do on multiple vehicles here in the South Florida hot lands. And . . . I'll continue to revisit this thread as my tests progress in coming years.

As always, you comments/suggestions/critiques are welcome.

Regards . . .

P.S. Not to dwell on this in this thread, but a small but occasionally smelly little oil leak I had on the front valve cover seal (running onto the header) has stopped since I installed the synthetic two months ago (and this is not the extended "high mileage" version that has additives for that either).
tightened the front cover ( a couple of the bolts were literally only finger tight after 20 years).

 

Hi Club Lexus Members,

I have some feedback on the synthetic oil change and the oil analysis. But first some new info: I had to sell my 2000 RX this Spring. I really didn't want to, but for reasons beyond my control, I had to take possession of another vehicle. There simply wasn't any room in the driveway for the RX300 it so I put the word out amongst friends. It went to a good home, with a mechanic in the family too . They needed dependable transportation for commuting to school. I also gave them a bunch of parts I had planned to install, but never had the time in the last couple years. They'll get some good use from that RX. Moving on . . .

I promised I'd feedback on the oil analysis if I ever did that. Well, I did have it done, but not on the 2000 RX300 (@~50k), but on a 2011 For Fusion (@~22k). I did the switch to the 15k synthetic and 20k filter on both the RX300 and the Fusion on 7/25/2020.

The RX300 received:
1) 5 1/2 qts 5w-30 Mobile 1 Extended Performance 15,000 Mile Advanced Full Synthetic. (For future: Note that there is also a "high mileage > 75k miles" version of this). And . . .
2) A Fram XG3600 Ultra Synthetic 20k filter

The Fusion (2.5L w/ FI) received:
1) 5 1/2 qts 5w-20 Mobile 1 Extended Performance 15,000 Mile Advanced Full Synthetic (For future: Note that there is also a "high mileage > 75k miles" version of this). And . . .
2) A Fram XG3614 Ultra Synthetic 20k filter.

As mentioned, the RX300 has now gone onto greener pastures, but the Fusion is still in the stable. On 7/25/2020 the Fusion had 15,950k miles when I did the changeover to synthetic. It had 24,021k when I sent in the oil sample a couple weeks ago. So the Fusion has run ran 8121 miles in two years on the tested oil. I've attached the Analysis Report.

Based on that report (and our ~4k/yr mileage use), I'm going to run that run the Fusion another year on the current oil and filter and have it tested next May (ie 3 years in use). Of course I'll continue to look at the level about once a month an add a bit if necessary. What I'm seeing here that that the oil industry's recommendation to change even this extended synthetic oil at a maximum time interval of one year, may not be accurate for all owners' environments. I believe we also have to consider here that the Fusion only saw 8121 in two years.

I'll be interested in any comments you care to offer on the test results or otherwise. I'll also continue to update this thread as time passes when I have new info (unless you don't want the "oil test results" posts here because the test subject is now a Ford, haha).

Regards . . .