synthetic 5W-30 or 10W-30? - Toyota Nation Forum : Toyota Car and Truck Forums

importcar · 10-08-2008, 01:13 AM

My 01 Camry 5S-FE has 123,000 miles. I want to try synthetic but I'm not sure what viscosity to go with. My car has no leaks and oil consumption that I know of.

uibalnme · 10-08-2008, 01:23 AM

What does it say on the oil cap? On my gen3.5 the recommended oil viscosity is printed on the cap.

Stillrunning · 10-08-2008, 06:13 AM

I've just tried Ow-30 Mobil 1. I've not done oil analysis yet but it gets flowing very quickly on cold start-up. Mobil says it meets or exceeds 5w-30 or 10w-30.

importcar · 10-08-2008, 08:07 AM

The owner's manual says 5W-30 but I heard 10W-30 is better for high mileage engines.

rty · 10-08-2008, 03:07 PM

Quote:

Originally Posted by importcar

The owner's manual says 5W-30 but I heard 10W-30 is better for high mileage engines.

That's because higher mileage cars might have leaks or burn a little oil. If your engine doesn't have any problems you should be fine with 5W30. Usually people use 5W30 in the winter and 10W30 in the summer. My gen 4 manual has a graph with 5W30 for low temps, and 10W30 for high temps.

uibalnme · 10-08-2008, 03:27 PM

One thing to consider, a thicker oil will make your engine work harder. Think swimming in water, then swimming in mud.

I used 10W-40 once, and my MPG dropped from 33 to 28. So, after 3k on that oil, I went back to 10W-30.

touringcamry · 10-08-2008, 04:21 PM

There shouldn't be any difference once the oil is hot. The 5 and 10 for when the oil is cold.

In SoCal, you could be fine with 10W-30 year round but I'd say go with 5W-30 since it should help efficiency when it's cool.

importcar · 10-08-2008, 09:10 PM

Thanks all. I'll stick with 5W and see how it goes.

Black95Cam · 10-08-2008, 09:27 PM

i'lve been using 5w30 all year around.. as hot as 110+ and as cold as low 20s...

gladis · 10-08-2008, 10:34 PM

A little bit OT, but there shouldn't be a problem in switching viscosities, is there? Between 5W-30 and 10W-30, that is.

Black95Cam · 10-08-2008, 10:48 PM

Quote:

Originally Posted by gladis

A little bit OT, but there shouldn't be a problem in switching viscosities, is there? Between 5W-30 and 10W-30, that is.

nope.. not really...

touringcamry · 10-09-2008, 03:20 AM

None at all. You can even mix them together if you like.

importcar · 10-09-2008, 08:05 AM

What about mixing different brands?

Black95Cam · 10-09-2008, 08:50 AM

manufacture dont recommend mixing brand but you can... the manufacture perfred if you stick to one brand of oil..

nikita · 10-14-2008, 09:11 AM

SAE J-300 is the specification for motor oil viscosity. The "W" spec is misunderstood by most everyone. Read it here. http://www.infineum.com/information/viscosity.html

Note that the difference between 5W and 10W is the Cold Cranking Viscosity at -25C vs -30C. If you are in California, Texas, Florida, etc, its not going to make any difference. The reason 10W-30 is preferred over 5W-30 for some high-temperature and high-mileage applications has to do with base oil and additive chemistry. Multigrades are manufactured by taking a thin base oil mixture and adding polymers that dont allow it to thin out as much at high temperature. Pour point depressants are added to keep wax crystals from forming and thickening the oil too much at very low temperatures. The problem is that a thinner base oil tends to oxidize and evaporate more easily, leading to higher oil consumption and possible sludge if drain intervals are pushed way to far, like 10k miles. Note that oil chemistry has vastly improved over the years, so these issues are much less than even just a decade ago. Synthetic 10W-30 is really straight 30 that happens to meet the low temperature spec without any polymers. I dont use syn because it simply is not worth the extra money (2-3x) due to the vast improvements in conventional oils in recent years.