I recently bought my '02 4Runner from a private seller, it has 67k on it and the owner used regular oil on it. Is it too late to change over to synthetic oil? Would it really make that much of a difference at this point? A friend of mine who worked at one of the local quick lube shops told me that if you start with regular oil, you should stick with it and not switch over. Same thing goes for synthetic, if you start with it, stick with it and don't switch.

 

i switched at 52k miles and no problems.. its your choice... keep an eye (if you do switch) on head gasket leaks and rear main seal leaks..

 

May be a dumb question but does switching to synthetic affect the head gasket and main seals?

 

no but old school way of thinking is that dyno oil helps "clog" any small indescrepencies in the seals where as synthetic doesnt. it actually cleans all the gunk out eventually exposing possible irregulars in the seals.. but to my knowledge its not that big of deal unless you have a lot more miles on it..

 

It doesnt effect head gaskets but if you do have a oil leak anywhere it will effect that. Auto Rx is a great product to safely remove any crap thats inside your engine but you can only find it on the web.

 

No problems switching. Amsoil has a product that 'preps' the engine for their synthetic. I switched at 40k and everything ran a little smoother. Other than fewer oil changes you might not see much difference.

 

I switched to amsoil at 85k and have zero issues, and that was 10k miles ago.

according to synthetic oil manufacturers, synthetic switch will not create oil leaks, but if you already have them, it will leak more.

at least thats what I found in research before I made the switch.

 

i dont think its a problem to go from normal oil to synthetic but i heard its bad to go the other way around.

 

thats an even older wise tale.. you can go back and forth. i read that somewhere i wish i could remember i would post the link..

 

amsoil engine flush then amsoil oil!

 

i switched to syntec blend at 136k and fullsynthetic at 145k

 

go ahead and change it. as far as the old wives tale of sticking with what you swapped with...its just that. although i'd stick with whatever youre switching to for a while at least. dont go back n forth every change...

you will notice a difference in full synth in the motor. it'll just feel happier..

 

KyleT - Any change after the switch to Full Syn? Did you extend your service intervals? My '95 3.Blow 4run (with 120K and runs great) has been run (like a moron) with Frams and very regular changes (3000 or less) of dyno and some blend. After too much reading in the forums, the Frams are no more and I am considering Full Syn and better filters (mobile 1 probably).

BUT, (Opinions please chime in!) Is it better to go with the blended over Full Syn since I have so many miles and an older vehicle. With possible damage from the (insert moron quote here again) Frams? Thanks

 

i go 7500 miles. I was gonna try 10K but it just started looking a little dirty. I have thought about changing the filter only at 2500 and 5000 but never did. It runs really well, does not burn or leak a drop.

 

oem or napa filters ork fine, or if you get the larger one that people run to hold more oil that would work too.

 

I switched to mobil 1 at 160k, I had a small leak in the oil pan shortly after switching but to my surprise it went away.

Just switch and keep an eye on it like the others said.

 

Switched to Amsoil/Mobil 1 @ 50k, now Im back on Dyno oil... at 100k.

Its a myth that synthetic doesn't need to be changed as often. 5k synthetic oil is just as dirty as 5k dyno oil.

Since I change my oil every 3k anyways, I don't find the purpose in using ridiculously expensive synthetic.

 

if you have dirty conditions, then yes, but it has been proven to last longer before breaking down. I can only go about 7500 before mine starts too look dirty. It has not lost its viscocity as far as I can tell. dino oil breaks down much faster and looks dirty when it is broken down.

 

The oil isn't going to be any cleaner no matter what. Its going to still have the same amount of debris contained in it, no matter what you put in there.

 

I might go with a synthetic blend the next change i do. I have used Frams a couple times too Dentonmac, so I guess we are both morons! I run a purolator now.