dfish

I'm approaching 90k miles and I was wondering what are your opinions on doing an engine flush? I've recently switched to full synthetic oil and I'm guessing the engine may have alot of gunk built up. Will an engine flush do more harm than good?

bob2200

Why are you guessing that? Do you have the service history on the car? Was the oil changed regularly, at what interval?

Lexmex

bob2200 is right. If we knew more service history, we could tell you if a flush would be good. I also would run at least go through one cycle with the synthetic oil and see what drops in the pan then (color and texture).

My uncle favors Kerosene as his weapon of choice, but I prefer Liqui Moly Engine Flush, though there are others out there, just depends on availability.

TunedRX300

I recented used Auto-RX, which was recommendated to me by Lexmex, to stop a seal leak. Kind of related to the leak, ARX cleaned hard sludge deposit off my engine. My leak after 2 cycles of treatment have slowed also, perhaps oil is getting to the seal as before it is blocked by the sludge...
ARX is different than other chemical engine flush. It is made up by three natural esters (similiar to Group 5 base oil used in Redline engine oil), which work very slowly over around 1.5K miles to disolve sludge and let oil filter to catch them.
Here is what I found in my oil pan after I cut open the filter used for ARX treatment.

satxrx

I'm also using ARX right now but still too early to tell if it's effective in cleaning out the engine... But I've heard many positive reports. As for whether or not you should, I'd think it should be alright. Esp. if you don't know the service history and with all the talk of engine sludge in the RXs you are erring on the side of caution, IMHO. Good luck.

dfish

thanks for all the good advice. I didnt really know much about maintaining cars before. I used mostly dino oil at 5k interval, +/- 1500 miles. Sometimes I would get it done earlier and some intervals longer depending on my schedule. Now that I learned how to do oil change myself thanks to the great DIY pages on this site I do it every 3000. Its mostly highway miles on the engine.

bob2200

The next question is where did you have your oil changed? If a quality oil (like you would expect a Lexus or Toyota dealer to use, hopefully) was used, oil changes at 5,000 mi [+/- 1,500 mi] with mostly highway driving should be no cause for concern or sludge suspicions. When you said "mostly dino", do you mean that you've been alternating with synthetic oils? In my opinion, the real concern is low-quality oil changes where recycled or otherwise inferior oil has been used and/or perhaps the oil filter hasn't been replaced. I'm assuming that you drive more than 10,000 mi/year (i.e., oil change interval is less than 6 months).

dfish

Most of my oil (10 if i remember correctly) changes were at a speed oil change place where they used penzoil oil. I did mix a few penzoil synthetic changes in there when they had deals on the synthetic.
I remember about 3 at toyota/lexus dealer (dino).

One the bad side:
1@ walmart but it was valvoline synthetic.
1@ jiffy lube oil change which I never went back to again.
1 more local quick lube place. i think it was penzoil oil they used.

I think that covers it all.
I wish I knew more about oil and maintenance earlier!
Thanks for the help.

bob2200

I think that's the kind of information that is needed to get good comments. I don't have enough experience with that situation to comment further.

TunedRX300

Did you buy the car used? 10x 5K only gives 50K
Quick lube places typically uses cheap bulk oil made with minimum additives on perhaps recycled base oil. But your miles are mostly hwy so if there is sludge, it should be minor.
I used M1 since my 3rd oil change, before I got into oil analysis I did not know how oil is doing in my RX. The minor sludge in my case may be that 1mzfe used up TBNs after 6K and I just did not know it until I change oil at 7.5K.
IMHO, you can finish your current fill of GC until 6-7K, but synthetic oil won't clean sludge if you have some. If you wish to have the peace of mind of a clean engine, you can run Auto-RX for the next oil change and cut open the filter to exam what is trapped in filter media element.
If you needs to be sure, just send a sample for a UOA. I will do so myself for my GC fill.

bob2200

The way I read it, it's approx. 10x at the speed lube place, 3x at dealers, and another 3 as listed; for a total of approx. 16 changes (5,000-6,000 between changes from new).

dfish

Thanks! I got the car new.

How much does a UOA cost and where can I get it done?

I think I'll try the Auto-RX treatment at the next oil change and do an experiment to see what is trapped in the filter.

TunedRX300

UOA is around $20, it gives good data on your driving style and condition. I found Total Base Number, wear metal, flash point, and viscosity useful. But UOA won't give you indication of whether you have sludge.

I have used Blackstone and Oil Analyzer. PM me if you need more info

Hint: I use other 1mzfe owners' UOAs posted on BITOG for an oil that I am interested in. That gives me a ball park range on oil change interval, I then do one UOA on my own. So as long as GC (or M1) does not change its formulation, I have a pretty good idea when I should change oil.
$20 can be recovered easily over 2-3 oil changes: w/o data, I would drain oil that is good @ 5K, but that oil maybe is good until 7.5K.