Changing From Conventional To Synthetic Oil - Corolland: the Toyota Corolla Forums

2003 Corolla -- 168,000 miles. Have always used conventional oil, but for the past 2 or 3 oil changes, repair shop has suggested I switch to synthetic because of the high mileage of the car. I have always changed oil every 3,000 miles (give or take a couple thousand) and the car has had very few problems other than the normal maintenance. Can anyone advise as to whether I should make the switch or stick with what I have been doing? I know very little about these things so must rely on other's expertise. Car still gets great gas mileage. I do sometimes hear a light tapping noise with very light acceleration, but that goes away quickly. Happens more in cold weather. I hope to keep driving the car for many more miles. Thanks for any advise.

I see no reason to switch at this point, especially with your short change interval - stick with what you've been doing, car seems to be running well with that recipe.

Changing to synthetic - especially if you don't push the oil change interval longer (7000 to 10000 mile oil changes) - is more of a waste of money at this point. The quality of conventional motor oil now is significantly better than conventional oils in the past. In some cases, current conventional oil can exceed the performance of some early synthetics in terms of high temperature stability and solvency.

If you want to read up some what others think - try hitting the Bob is the Oil Guy forums (BITOG). Just wade through the sales pitches for Amsoil and Lucas - then you'll find some great info on lubricity and tribology - lots of VOA (virgin oil analysis) that shows you what many oils have in terms of chemical make-up and additive packages.

Thanks for the advice!

Doesn't it consume much oil between oil changes? I would switch to a high mileage oil, such as Castrol GTX High Mileage which is part synthetic with a viscosity that is slightly heavier than your average 5W-30.

"Castrol GTX High Mileage is the premium engine oil for engines with over 75,000 miles. As your engine ages, its performance decreases and oil breaks down faster. Over time, seals deteriorate, gaskets become brittle and oil consumption increases, leading to reduced performance. Castrol GTX High Mileage combats this aging process and provides superior protection against harmful deposit build-up in higher mileage engines to help extend engine life.

Features and Benefits:

· Contains superior detergency that fights harmful deposits in higher mileage engines*

· Utilizes special base oils to provide superior protection against oil burn-off compared to leading oils**

· Contains seal containers that provide added level of protection and help reduce leakage

· Reduces deposit formation to minimize compression loss and maximize engine performance"

http://www.castrol.com/liveassets/bp_internet/castrol/castrol_usa/STAGING/local_assets/downloads/p,q/pds_castrol_gtx_high_mileage_2010.pdf

http://www.walmart.com/ip/Castrol-GTX-High-Mileage-5W30-Motor-Oil-5-qt/17253557