My 03 has 69K on it. I just bought it from the dealer 2 months ago, and its due for its oil change. I'm assuming its been using dino oil, but I'm not sure. Here's my plan...Correct any problems for me.
Change out oil with 1/2 mobil 1 synthetic and 1/2 dino oil.
Use bigger mobil 1 filter.
Wait 4K miles and change oil using all Mobil 1 synthetic.
Do 5K oil change intervals for the rest of the car's life.
My Max is used 1/2 highway and 1/2 city.

 

Just use all Mobil 1- not half. You should easily go 5K, more like 7.5K
OH, and be sure to check the oil level every 1000 miles with that 3.5L!

 

My engine doesn't burn a bit of oil. I will, of course, check it often when going synthetic.

 

^^^^^^

once you switch to synthetic, you cant switch back to regular dino oil,
it will mess around with your seals
and when going to synthetic.. just pour all synthetic in, dont mix 50 synthetic 50 dino

 

I agree. I have 65 K miles on my 04 and the last oil change I went just short of 10 K miles, with an oil test of the oil that went that far. The test said there was still life remaining in this Mobil 1. But then I do a lot of highway driving. If you do mainly city driving, you probably should stick to a 7.5 K mile OCI using Mobil 1.

 

that's actually an old myth...you can switch from conventional to synthetic and vice versa back at any time.

you can do a run of auto-rx (will gently clean your engine with no harsh solvents....more info on http://www.auto-rx.com/) and switch to synthetic at any time. Your seals will be fine.

 

buy some cheap oil.... do an oil change and drive it around the block a couple times and change it again to synthetic. it'll help clean out all the old oil

 

Nonsense!

I would do an Auto-RX trial first. See www.auto-rx.com and do a search in the Additives Forum of www.bobistheoilguy.com. This product will clean your engine internals, ring packs and combustion chamber, while rejuvenating your oil seals. It is not available in stores, only on-line. Look for a coupon on BITOG.

Once you switch over to synthetic oil, you might want to use Valvoline Synthetic Oil Treatment along with the oil.

 

I don't know about that. One of my Dad's customers couldn't pay his bill so they took his acura TL. It had synthetic oil and when the broker changed it to conventional and they started the car, the car didn't want anymore. My Dad's customer found that to be hillarious.

That process looks convincing enough to me though, but I won't ever switch just to be safe.

 

quick answer:

dump old oil, fill new synthetic and use stock filter.

 

Forget the millions of other possibilities that could be contributing factor to it not working...

You can change back and forth without issues. I know.. because I've done it. The only dilemma that some should consider, is that on higher mileage vehicles, switching to synthetic may cause the motor to consume more oil or leak due to synthetic's inherent nature of being a lower viscosity.

 

Synthetic oils are intended for use in mechanically sound engines. In those engines, oil consumption can actually be reduced with synthetics because of the lower volatility of the oil; better sealing characteristics between piston rings and cylinder walls; and because of the oils resistance to oxidation. If a high mileage engine does use oil after switching to synthetics, it has been my experience that it is due to the synthetic oil becoming contaminated from deposits left behind by the petroleum...and dirty oil will not seal as well as clean oil does, thus resulting in increased consumption.

Concerning the viscosity, in order for a lubricant to be classified in any SAE grade (5w-30, 10W-30, etc.) it has to meet certain industry guidelines with regard to viscosity. It makes no difference whether it's 5w-30 petroleum or 5w-30 synthetic...the oil has to maintain a standardized viscosity or it can't be rated a 5w-30.

 

Thanks for this post.

Question: I bought a used 1976 Celica that burned oil, but it burned even more oil when I used synthetic oil in it. I suspect that the engine had been beat by the previous owner. I always assumed that it burned more synthetic than dino oil because the synthetic oil was more slippery and would slide through places where the dino oil could not slide. Do you have any other explanation for why this occurred? Thanks !

 

As you know, another advantage of a good synthetic oil is the uniformity of the molecules...and that uniformity reduces friction between moving engine parts and within the lubricant itself...that slippery-ness factor. Perhaps there's some validity to your theory...just hard to say. But the only instances I have seen where oil consumption increases is due to the synthetic picking up crud left behind by the petroleum oil and becoming prematurely dirty. The 20R engines used in Toyotas of that vintage were pretty tough...I had one too. In fact that was the first car where I experimented with synthetics. You're probably right in that the engine was abused before you bought it. I have a customer who still has an '83 Celica...he's the original owner and he switched the car to AMSOIL in '92...he's active duty military and every few years he drives it cross country to his new duty location. Still no oil consumption.

 

The 87 Celica was the first production engine with 4 valves per cylinder. That 2 L, 4 cylinder engine would move, and you could feel the engine jump when the RPMs passed about 3K RPMs. The only problem I ever had with that engine was the oil consumption. IMHO, Toyota no longer makes products of the quality of that 87.

 

6-7k is just fine.