GSquicksilver

After years and years of driving and always using conventional oil on all my cars, I finally switched over to synthetic oil today for my GS400. I decided to go with Mobil 1 5w30 since it's a good price at walmart and plus it's easier to get than amsoil. I'm crossing my fingers now hoping there will be no leaks. My car has 126k miles on it now and does not have a single leak.

I've been doing research on synthetics (excluding amsoil) comparing Mobil 1 and Castrol Syntec. From what I've read, there has been many debate that Castrol Syntec is not true synthetic. There are claims that it is not made of PAO, whereas Mobil 1 is. Therefore, I decided to go with Mobil 1.

I'd like to know the opinions of others on this board about Mobil 1 vs. Castrol and if I made a good choice. Also how many miles do you guys go between oil changes running synthetic? Thanks.

LEXUS_KID

iTrader: (4)

You made the right CHOICE

GSteg

iTrader: (15)

go mobile1 synthetic!

Castrol is synthetic, but not 100%. From what I heard, manufactors need a certain percentage of synthetic material to be considered "synthetic." Kind of like how you see "made in the USA" stickers on some products, when infact a lot of those products are not 100% made in the USA.

dwoods420

Hello,
I get synthetic oil in my 2001 gs300. I have been doing it since 35,000 miles. I now have almost 80k on the car. No problems. I get it done at Lexus. I am not sure what brand they use. I just looked at a invoice and they only write Synthetic 5W30 OI.
Lexus says the Synthetic should be changed every 5,000 miles. I change it every 4,000.
Whenever I check the oil after 3,000 it still looks brand new. I am sure it can go 5,000 with no problem.

GSquicksilver

do you guys recommend that i go 5k on this oil change before i change the oil again or should i do it a bit earlier since this is the first time i'm using synthetic? i'm just curious if the left over conventional oil that did not drain all the way would have any effect on the synthetic oil.

GSteg

iTrader: (15)

If it bothers you, change it at 5k . You wont be doing any harm.

blacksc400

iTrader: (4)

I always change my oil l( of course synthnic) every 2500 miles... won't cost much anyway... just all my cars' oil change due on the same time.. so I always have to change all of them(depends on many cars I have at the time, )
My last SC had 170K on it and when I use Mobil 1 synthnic there isn't any leaks..

engin_ear

iTrader: (1)

I've been running Mobil1 5W30 since 20K miles. I now have 116K. No problems, it's great. Change every 5000 miles with filter change. The best thing is if you don't get to it in time you can still go 7-10K without any problem (not recommended though), like middle of winter. You don't need to change synthetic at 3K intervals, it's a waste of time and money unless you're really killing the car. As long as you use a quality filter - Toyota, Mobil1, K&N. No Fram, Purolator, Mighty, JiffyLube, etc.

suge66

I've always been told that when u shift to synthetic from convetional, u will have leaks. It seems to me that this is not trrue according to u guys. I have 88k on my car right now, is it safe to shift @ that milege? I dont have any leaks right now, and amsoil is obtainable near me on a regular basis. Is that better than mobile 1?

Vette Boy

I switched my 02 over to synth right after I bought it (with 70K miles on it). No leaks, no issues.

I use Mobil1 'cause it good, inexpensive and I can get it at Autozone. IMHO, Amsoil isn't any better that other choices, just more $$.

I switch out my Mobil1 every 5-6K miles which is about 6 months. I run 5W-30 from November to April, 10W-30 from April to November.

GSteg

iTrader: (15)

The leak rumor started from those who have bad seals to start with. If you have leaks, think of it as a GOOD thing because you know what's wrong. I personally rather know that I have bad seals, than to drive with bad seals (conventional oil covering up).

DASHOCKER

iTrader: (2)

Amsoil stays cleaner longer. I change it out every 6k. Tried mobil1, and it doe not last as long

AUGuy21

GSQuick,

I began using Valvoline SynPower around 95,000 miles and just switched last week to Mobil 1 Synthetic. I've had no leaks from switching to synthetic, however, the longest I can go before a change is 3,500 - 4,000 miles, and 4K is stretching it. I've got 101,500 now and my oil light came on around 3,800 miles after last change. I've heard that in higher mileage cars, synthetic will NOT allow you to prolong your time between oil changes... Just my two cents...

e-man

We have oil lights on our cars? I've never seen it. When does it come on? What does it mean?

engin_ear

iTrader: (1)

Amsoil is supposedly better but might be overkill for a street car. I don't think there are very many engines that have died while using Mobil1.

Obviously the earlier in mileage you shift to conventional, the better, and the less likely you will have seal leaks.