rcm3

First tech question::FLAMESUIT ON::

MY rig has got 175k on the clock and its been running dino-oil for all its life. I subscribe to the school of thought that running syn-oil in a motor makes it last longer, but...

I have also heard that switching to syn after prolonged use of natural oil can cause problems becuase the high detergent content of synthetic oils will clean out all the gunk and buildup into your engine - which in the case of high mileage switches can cause damage as it is broken loose.

Does this make any sense? What if I were to switch to a blend for a couple oil changes and then go full syn in order to smooth the transition and try to capture as much as possible in the oil filter?

Thanks for your help!

Bob_98SR5

that is why you would run an engine flush prior to switchign to synthetics. then you'd run regular dino and switch out the filters at around 3k and 6k to capture and discard any large particles. then you'd replace the old dino w/ synthetic and a long life filter.

search "auto rx". they seem to have this procedure down. expensive to go through their process, but lots of people swear by it. i did this w/ no significant effect, but its probably b/c i only had around 70k on the clock

bob

Jeffires

I don't have enough experience to answer this, but I've heard that theory before- some people recommend to change automatic transmission fluid but not to flush the transmission when it gets very high mileage for that same reason.

rcm3

As far as I know that is because when they do these 'flushes' they don't replace the tranny filter as well. So when they flush, everything that has collected in the filter over the life of the tranny is pushed out into the system causing damage. But a good analogy anyway. There can certainly be considerable buildup expected in a motor this old.

rcm3

Thanks for the autoRX suggestion. I searched it and actually came up with a bunch of threads directly related to my original question that I didn't see when I searched initially. Looks like the responses to its use have been good overall and so that is the way I am going to go. According to searched threads, some just switched cold turkey, but better be safe with the autoRX than sorry.

Jeffires

Luckily, I have been the only owner of my truck and have always kept new fluids and flushed tranny, radiator, block when needed. I have heard older mechanics warn against flushing a transmission, particularly an old one that hasn't been flushed. Flushing the crankcase a couple of times sounds like a good idea to me.

Toyo4x4

At this point, I'd say keep using dino. We all don't know the condition of your truck and at 175K, it MIGHT need a rebuild a few years down the road...who knows?? One of the myths, "switching to syn CAUSED a leak" isn't true. It is because some of the gunk that you mentioned is cleaned out of a seal that has been worn or damaged, ie:unplugging/cleaning a hole/leak that was already there and stopped up. I'd save the extra cost of syn right now and wait until the engine is rebuilt and then start with syn after break in. I've used AutoRX with great success. I had a plugged PCV valve that caused an oil burning/ low oil issue. I did the two bottle treatment and gained back MPG and a smoother running truck.
If you feel you must switch, again at this point, semi-syn would be the most I'd go.

Also, a lot of info about lubrication can be found here: http://theoildrop.server101.com/cgi/ultimatebb.cgi

trd90toyota

Well, hope this helps...

https://www.yotatech.com/forums/f123/change-synthetic-oil-high-miles-truck-7236/

There is much info on this thread...

rcm3

Great thread. Thanks for posting it. Looks like I should verify that there is no leaks before I do anything else (autoRX,switching to syn).

To the guy that was asking about Royal Purple: Its FANTASTIC! I am not sure if I am going that route for the toyota but I just switched to using it in my m3 and love it! It is in my motor, tranny, and diff. Smoothed my engine and removed excess noise and ticking and it also smoothed my shifting. My first gear notchiness completely disappeared after a week with rp in my tranny.

rcm3

Anyone know where to buy auto rx? Is it sold at auto parts stores or do I need to buy it from the company directly?

Bob_98SR5

direct from the company

trythis

I read a consumer reports article that tested synthetics and different brands of oil in NY city taxi cabs. They did extensive engine tests before and after the (I thin kit was ayear) of useing the specified oil. NO difference what so ever in engine wear as long as the oil has the API stamp on it, they said it works fine. Why spend extra money? Its good advertising, yes, ,and you don't have to change oil as often , but other than those two compelling arguments, dino