Best oil for RB25DET during hot summer months?

[Nguyen]

I've got an R33 which has done almost 100,000km and summer here in Perth is usually 35deg days, sometimes over 40. I know factory oil specs are 7.5w30, but is it wiser to use a thicker oil during our hot summer to reduce oil breakdown? I've heard that you should use oil close to factory spec, because of bearing cleanances, but then i also read that you should use thicker oil in hotter climates, which is true? Car's mods are just exhaust, and fmic. Don't want to spend $100+ on an ester based synthetic though. Not so much after brand recommendations, more a viscosity range, and whether a 50 weight oil is too thick?

Have been considering the following synthetics:

Motul 8100 X-Cess 5w40

Mobil 5w50

What can you recommend, from your experience and knowledge?

cheers

[RB30-POWER]

I would recommend a 10w40 in all conditions.

The factory recommendation might be fine in Japan, but incase people didnt notice we are in Aust, the climate is a hell of alot warmer here then in Japan generally anytime of the year.

But thats only my 2cents.

[(B1) MR_fanny]

yeah im currently using motul 4100 10w40 just because i didnt want to go too thin (in summer) and the fact that my engine has done 100ks too.

[Kinks]

i'm using motul 8100 year round. the only difference being i don't thrash my car in hot weather, aside from being harder on the engine you make less power anyway so there's no point.

[cameron]

Castrol Synthetic Type R 10w-60 I found is best for hot weather. - Around $60 - $70 depending were you get it from.

Jun

[25det]

using mobil 1 5-50W since i got the car not probs....

[Busky2k]

That castrol 10W60 stuff is too bloody thick. That belongs in race cars, or smoke blowing Sigmas.

Motul 8100, Mobil 0W40, Castrol 0W40 or Shell Helix Ultra 5W40 would be a good choice for all year round use.

[Cubes]

The Motul 8100 5w40 is what I will be running when this motor clicks over 10,000km's.

Until then I am running the Motul 4000 10w30. Should ensure the bores are run in properly.

The Motul 8100 stuff really is good value for money.

I am considering spending a little more on the Motul 300v providing I can extend the drain intervals, this all depends on how the oil reports come back.

I am going to change the 8100 every 5000.

If I can get 10,000 out of the 300v I will be better off.

[gatty]

i use Mobile 1 - 5w-50

$64.95 for 5L

[Cubes]

Is the Mobil 1 we get in AUS the good german stuff or is it the crap stuff?

Apparenty if it is made in Germany it states "Made in Germany".

I've had a look with no luck.

Which is the reason for going with the Motul 8100, they tell you it is 100% a PAO oil. Not a mix.

[25det]

i think its made in new zealand??? but the price of it went from about $50 to $65 as gatty said but now its supersyn or something but still 5-50W i dont know its just worked well for me.

where can you get motul 8100 in bris (i dont think super cheap auto has it, cant remember if autobarn has it though)??? is it that much better??? what sort of prices???

[Cubes]

Autobarns have the Motul stuff.

Not all of them do.

Come to think of it I have also noticed the price jump in Mobil 1 oil.

Possibly we are getting the good stuff now.

[Whale_Ryda]

do any of u guys do an engine flush? after doing that on mine the oil pressure is consistantly higher

[gatty]

hows you flush it?

/please don't tll me with a garden hose

[Cubes]

Engine flushes can cause nasty problems.

I have heard of simply switching oils can also cause the same problems.

The bloke who did the machine work for my rb30 said the most critical part of keeping a motor running for thousands of km's is to select an oil and don't jump from one oil to another.

On that note I saw a VL Calais (shopping for my little sister) that had done 196,000km's on what looked like the origional oil

The oil on the rockers were so thickly coated it was unbelievable.

BUT the funniest part is it ran perfectly smooth, no knocks or ticks.

Gut feeling told me to steer clear of that one, especially after noticing the overflow bottle was empty & the temp would climb up to 3/4.

[lwells]

Flush is an elastic term. It can either mean the use of flushing products -- which usually contain heavy detergents -- or it can simply mean a more thorough oil change. Rather than simply dropping the oil and replacing, some people "flush" by dropping part of the old oil, filling with new oil, dropping all the oil, refilling, etc.

LW.