Tuesday, October 17, 2006 - 12:16 am, by: Yang Luo(Steven)
i have been looking around to find the best one for soarer.i have asked on the chinese forum.they said if you always go beyond 5000rpm you better get 5-50w to protect you engine.is that right. i am using mobile SYN 10-30w is this one the best one for our soarer?
Tuesday, October 17, 2006 - 09:16 am, by: Benjamin Burgess(Jampac)
stick with a 10w for 1jz, 5w is too light. I rotate between 10w-30 and 10w-40. Currently have penzoil semi synthetic 10w-40. However for my next oil change I brought this nulon stuff from autobarn, 10w-40 fully synthetic, API grade M, cost $54 bucks for 6L's. Pretty good value for full synthetic.
Tuesday, October 17, 2006 - 12:48 pm, by: Tom Burgan(Burg)
Both are suitable but in the end just comes down to personal preferance. I always go for the 40w. You should really do a search on this, probably one of the most covered topics.
Wednesday, October 18, 2006 - 02:41 pm, by: Benjamin Burgess(Jampac)
From what I've heard, lite weight oils like 5W-xx and 0w-x are just not suited to the 1jz cylinder head. Was never designed for such thin oils on cold start, so its possible there'll be increased wear on cold start until the oil gets up to its warm visocity of 30 or 40 or whatever it is.
0W is more suited for places were it is really cold, like in europe as you want good oil flow at extremely cold temperatures, not the case in australia.
Wednesday, October 18, 2006 - 04:01 pm, by: Cihan Aday(Cihan)
Most 0-40's are 'thicker' at operating temp than a similar 10-40's for example. They're just 'thinner' at lower temps for increased low temp lubrication.
Its not as simple as 0W is thin, 15w is thick, they each have curves of temperature vs flow under standard conditions.
If you block out all the mumbo jumbo, a good 10-30w is what most of use should be using. Motul 10-40 semi-synthetic works great for me. I'm currently trying out the 5-40w fully synthetic version and its just as good. I'd expect it to be more viscid than the 10-40 at startup, and less viscid than the 10-40 over and at operating temperature to provide some more high stress buffering against wear, and promote better oil pressure.
Wednesday, October 18, 2006 - 09:35 pm, by: Dominic Kelly(Drk_awd)
I guess it's partly because oil technology has moved on quite a bit since the JZ engines were designed. Oils with wide viscosity ranges back in the early 90s were chock full of friction modifiers (Viscosity Index Improvers) which quickly broke down and sludged up especially in highly stressed engines. That's most likely the reason for the relatively narrow 10w30 range specified by Toyota (which was pretty cutting edge back in 1991).
Modern synthetic oils don't require the friction modifiers that mineral oils do (or at least nowhere near as much) which is why we commonly see oils with wider viscosity ranges nowadays eg. 0w40 or 5w50. If your engine is in good condition the 0w and 5w oils won't hurt. If your engine is blowing smoke or leaking everywhere then thicker oil is only a bandaid solution anyway.
Thursday, October 19, 2006 - 12:17 am, by: Michael Sztyk(Sli1)
Im also currently trying out the Motul 5-40w oil. Pretty good stuff, only thing it seems im blowing a puff of blue smoke only on cold starts. Im assuming id have to move to a 10-40w oil?
Previously i was using Mobil 1 Syn 5-50w.
Had my turbo's rebuilt with steel wheels earlier this year so the turbo seals should be ok.
Anyone else thinks it would be valve stem seals?
I am yet to also do a compression test but as i said, its only on cold starts.
Thursday, October 19, 2006 - 08:26 am, by: Dominic Kelly(Drk_awd)
I'm using Fuchs Titan 5w40 and have no problems with smoke on startup. My turbo might need a rebuild soon as I think I get just a bit of smoke under full boost. I only top up about 500-600ml in 5000kms with the Fuchs oil so it can't be too bad.
Try the 10w40 and if it goes away then stick with it otherwise you might have to fix the source of the leak (or just leave it). It could be the stem seals, if it gets worse you'll see puffs of smoke when driving around and not just at startup.
Thursday, October 19, 2006 - 12:00 pm, by: Benjamin Burgess(Jampac)
I can actually go full oil change interval without topping up. The most I've measured it using was around 100mls after 5000ks. Thats using 10w-40. However I reckon I lose most of my oil out of the rocker cover gasket (common 1jz problem). Absolutely top engine 1jz.
Thursday, October 19, 2006 - 12:40 pm, by: Dominic Kelly(Drk_awd)
They are a great engine and 100mls is next to nothing. I forgot to mention mine is a 1.5jz and it also had a slight leak from the front main seal which is now fixed.