Castrol GTX 5w20 and Toyota 4cyl.

[daemonite]

I know that most conventional 30wt oils shear down to a 20 weight anyway, would there really be much more wear and tear on my 2az-fe (scion tc) if I just go with a 5w20.

And aren't toyota engines built to tight specs just like honda? ford? So is there any reason not to besides the fact that toyota recommends 5w30 in the manual?

The whole reason I'm thinking about it is because my girlfriend's car uses 5w20 and we bought a couple of jugs cheap and her car is barely driven where as mine see a lot of miles quickly. So someone has to use that oil!

 

[ekpolk]

If you've satisfied yourself that there's no reason why Toyota has not jumped on the 20 wt bandwagon, then you should be comfortable doing this. If you do run 20 wt in this engine, just be aware that you're conducting a high-stakes science experiment. I'm not going to be the one to endorse doing this. That said, I doubt your engine will immediately melt down on 20 wt. If you decide to go for it, by all means, please do a UOA and post the results. Proceed with caution.

 

[haley10]

I think all American and Japanes manufacturer's desire getting CAFE credits. Whether they need them or not, they can be sold and transfered.

Either GM and Toyota haven't completed their testing yet or have and decided it's not a good idea yet with their current designs.

Until Toyota specs. (retro) 5w-20, you never really know for sure, what the issues might be.

 

[z917990]

I really would not use 5w-20 in an engine that specifies 5w-30. You run the risk of nullifying your warranty and possibly causing engine problems if you use the wrong viscosity. You're right, many 5w-20 UOAs look good, but I have only seen these UOAs in connection with engines that specify 5w-20. BTW, I use 5w-20 (Mobil 1 or Pennzoil Platinum) in my '03 Accord, but I use 5w-30 (or 10w-30 in the summer - Trop-Arctic, Mobil 7500 or Valvoline Durablend synthetic blend) in my '99 Accord. Both engines run well on the oils specified by the manufacturer and, at this point, I really do not want to experiment with cars that I cannot afford to replace.

 

[oilyriser]

you could always mix it half n half with 5w30

 

[daemonite]

well i threw in the 5w20 with a bit of VSOT to thicken it up. Runs fine, will post UOA in 5k.

 

[the_oil_dealer]

stright 5w20 in a Toyota 4cyl is a bad idea. theyre "bigger" 4cylinders with very 'angular dimensions.'

 

[Ray H]

Aw heck, go ahead and dump 5W-20 in your Toyota - manufacturer recommendations be darned. Just think of yourself as an insightful visionary. (Besides, what does Toyota know anyway? Even Hyundai now recommends 5W-20!) After all, it's your engine, right?

 

[daemonite]

quote:

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Originally posted by the_oil_dealer:
stright 5w20 in a Toyota 4cyl is a bad idea. theyre "bigger" 4cylinders with very 'angular dimensions.'

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the honda oddessey 3.5l v6 runs 5w20, even ford v8's...

 

[the_oil_dealer]

quote:

---

Originally posted by daemonite:

quote:

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Originally posted by the_oil_dealer:
stright 5w20 in a Toyota 4cyl is a bad idea. theyre "bigger" 4cylinders with very 'angular dimensions.'

---

the honda oddessey 3.5l v6 runs 5w20, even ford v8's...

---

But they have more forgiving rod/stroke ratios than the 2.4 toyota engine. That thing has a96mm stroke

I cant imagine the rods being too long, so that would give it (ESTIMATING) between a 1.55:1 - 1.45:1 rod/stroke ratio... that would mean that the rods will shove the pistons into the cylinder walls at more of an angle. Plus they sound clunky lol