4A-GE and syntethic oil

[Nookie]

What about the 4A-GE engine and full syntethic oil(5w50)?
Some of my friends say, that it is not right to use fully syntethic oil on old engine (bu why??)...
What should I use? Everyone says, that Castroll bagan to make bulls**t...

[NoHachi]

There is almost no real fullsynthetic oil on the market anymore. But beyond that, oil is just oil, synthetic is just manufactured a bit better sometimes.
What you need to make sure is that you get the recommended oil weight/temp rating (is 5w50 within specs?) and that you get the rest of the specifications good as well...there is a bunch of G-xx numbers on the oil that should match your specs in the instruction manual. Not many people do that, but it can make the difference between an engine that last 200.000 and 400.000 kms

[Mux213]

Nookie,

From what I've understood from reading is basically what Nohachi sais, most oils that you buy in the store that claim to be synthetic really aren't, they are semi-synth meaning they are plain old normal oil but with synthetic additives that improve the oil in one way or another.

The thing with these additives is that they often improve the oil in ways like enabling the oil to desolve polutents, making sure the oil does not leave any residue, making sure the oil lasts longer so you need less frequent oil changes before the oil goes bad etc.

Now this all sounds very good and indeed it is but with an old engine there is a drawback which is why people tent to say that you shouldn't use (semi-)synth oils in these engines. If you have an engine that has run with mineral oils for its whole life its run with oils that has deposited gunk, this gunk tends to build up around seals and that sorta thing. No problem at all, these engines are designed with it in mind, its often is just a few microns of the stuff anyways.

When you switch to the newer oils they tent to start to 'clean' your engine and slowly break the gunk away. Two results in this. First, the gunk starts to move around in your engine and if not filtered out quick enough by your filter (and if not clogging up your filter in no time) it is possible it may end up clogging up the smaller oil channels within your engine with bad lubrication of specific parts in your engine as a result.
Second, with the gunk being resolved on very old engines this can actually cause small oil leaks where the gunk has actually damaged the seals a bit.

Whether this is all true or not, or just and urban myth? No idea, but it always sounded logical to me. Its always been the reason for me to tell people not to switch to (semi) synth on old engines until you've rebuild your engine because in that case, with all new seals and a cleaned engine I do believe running (semi) synth has added value for money.

My mean reason for not switching to (semi) synth though is a different one, a simple matter of numbers.
I can go to the store and buy enough mineral oil for an oil change for 5 to 10 euro's. If I buy the right type of oil and I drive my car nicely warm before I abuse it, 4AGs last well over 300k before they need a rebuild. Just look around at the cars we have on the forum, we have MANY +200k km cars on the board and almost all of them run mineral oils.

I can also go to the store and buy semi synth oil for 20 to 30 euro's.
WHY?!?!?! WHY spend 4 times as much money just so I can say I use oil in my car that is slightly better??? Sure I might be able to do oil change every 15k km instead of every 10k km or whatever oil change scheme you use but then still its 2 to 3 times as expensive and still its questionable if my engine will really outlive my future wishes. I'm probably going to rebuild and tune my engine way before it brakes down anyways!

So I ask you, WHY in heavens name buy expensive oil if it only is slightly better.
Yes for a new rebuild engine I can understand. But for an older engine, it just doesn't serve a purpose!

[dAYTONA]

Like Mux said. I will just add, there there was a fellow on the toyots-mods list years ago, who like me had a 3T-GTEU engine in his Corolla, and one day filled it with 5w-xx Mobil one oil and after 5 minutes of warming up, the engine started to rattle, and knock. Till this point, he used mineral oil.

The build-up of sludge/gunk which goes hard from temperature can actually help keap your old engine together. And as Mux said, the synthetic oils will flush your whole engine clean. And who knows how llong it will last after this.

Mobil 1 synthetic oil is proven to give a coupe extra hp compared to other mineral oils. Mobil 1 synthetic is also notoroius for making small oil leaks, big oil leaks.

Before I tear my engine down for a rebuild, to avoid cleaning it later, I might run it on synthetic a bit ;-)

[Ivan141]

I'm running Valvoline 5W40 full synth (at least called full synthetic..i know it's not) since I put my latest engine in. I'm switching back to thicker semisynthetic oil though, it started to consume a bit more oil since temperatures started dropping.

[robokill]

RUnning 5w 40 full synth

This oil runs fine. We made the step on ivan's car if he keeps using 5w40 after 2 more refresh it will not use oil anymore!

[Ivan141]

It didnt use oil when we just put it in...now I already put in 2 extra liters.. (apporximately 5-6000 km's driven since the engine is in..)

[Michel H]

Had 10w40 Castrol GTX in my Blacktop. It was very thirsty, about 1ltr/1200km. Changed to Castrol RS 10w60 and since then I never had to fill up ?¿ But unlike the 16v, they have no oilcooler which is a bit strange heh ? Maybe it just gets too hotty ?

[Mux213]

robokill Wrote:RUnning 5w 40 full synth

This oil runs fine. We made the step on ivan's car if he keeps using 5w40 after 2 more refresh it will not use oil anymore!

Robo, you have a rebuild engine dude!

[Mux213]

Michel H Wrote:Had 10w40 Castrol GTX in my Blacktop. It was very thirsty, about 1ltr/1200km. Changed to Castrol RS 10w60 and since then I never had to fill up ?¿ But unlike the 16v, they have no oilcooler which is a bit strange heh ? Maybe it just gets too hotty ?

I remember reading something a long long time ago that the missing oilcooler was actually something many people pointed out as a problem and it was an upgrade many did when installing a blacktop into their car.

You might think about adding one...

But I could be totally wrong about it making sence, just read about it somewhere....