My yaris is due a service and i was checking what the manual recommends. The engine requires 10W-30 in a temp range of 0'f upwards. It can also take 5W-30 from 50'f downwards. I made a few phone calls and it seems 10W-30 is no longer available and that 5W-30 is fine. Can i go lower, say down to 0W-30? It never gets much above 80f here. In fact it hardly ever gets up to that so would i be ok with that oil? The transmission requires 75W-90 but i would like to know if i can go any lower than that. I've seen a 75W-80 which is only a little thinner so would i get away with this? I've heard of some yaris drivers using ATF in their manual cars to improve gearchange and make it less clunky but that oil is made to be pumped around the transmission right? The manual version doesn't have a pump afaik so is dependant on the oil being picked up by the gears. ATF may not do this effectively. Any suggestions? ollie
You can safely drop that first number down to 0 for your engine oil. That number just refers to the cold weather performance and a good synthetic 0W-30 will be fine. Otherwise, the 5W-30 will also work well. That's what I still run in my Elantra and it hasn't kept me from knocking the big numbers out. I couldn't tell you about transmission oil weights, but I can say that normally ATF in a manual transmission is a bad thing. The reason is that ATF is pretty caustic and unless a transmission is set up for it the stuff can eat through seals. I don't know if your car can handle that but I definitely wouldn't assume it can!
I would be careful with the oil in your diesel. In my Jetta, using the lower weight oil can cause problems due to the higher compression and blow by possibilities. I would check it out extensivally before you dropped the weight much.
Thanks guys. I think i'll stick to 5W-30 for now but maybe when winter comes around i'll try 0W-30....after some more research! Any thoughts on 75W-80 instead of 75W-90 in the transmission? ollie
I would go with 75w-80w synthetic gear oil in the tranmissions! I switched to this in my Miata 1993 mod. and find the shift much smoother. You would notice a differance with 75-90w synthetic as well . H
So off i went this morning to get my new fluids and filters. I got castrol magnatec 5W-30 fully synthetic (cheaper than others!) and some 75W-80 transmission oil. The new oil filter was smaller and i got a fright as it's o-ring was smaller too. However the seat has a large area and the o-ring sat lovely on it. No leaks either, which is nice..... I had a short errand to do after but it was hard to tell in the short time i was driving how much of an improvement there is. The gearchange did feel smoother though so it bodes well for a reduction in friction. Now i'm in a position where i can either fill up my tank to get a good picture of how much improvement (if any) i get. Or i can just run out this tank as normal and recover it somewhat. What would you do?!? ollie I got a new air filter too. The old one was a little grubby but not too bad.
Did you go with synthetic gear oil as well? It sounds like you did? or did you mean the lighter wt. oil [75w-80w] made shifting smoother? It probably would. Hal
I've been watching like a hawk but have yet to see much improvement. Having said that, i have been correcting the SG2 after a fillup so that will account for the apparent lack of improvement. It was under-reporting the fuel used. I'll have to wait until i fillup again and calculate it the old way. ollie
