What Oil??? 5w-30 10w-30 10w-40
 

whats the difference between all these oil. and what oil should i use for my car???. i drive a 93 first gen GS. with about 120,000 miles and running GREAT. i always went to cosco and they only carry 1 type of Mobile one and i always just use that one. its 10w-40 my friend said its not the right one for my car. can someone explain to me whats the difference between the numbers and which i should use.

under the hood on the cap it says 5w-30 but i think thats what your suppose to use when the car is new with few miles. but my car is becomming higher milage. thanks.

i use 10w-30 in the summer and 5w-30 in winter. 5w is better for the winter

I use 10w40 synthetic blend...

With that many miles, I wouldn't use 5w30, it's too thin, when it has little to no miles, yeah go head. Personally I would use
Mobil 1 10w30 all yr. round.
If you happen to notice that your burning oil, and this can only be determined by checking it, use Mobil 1 15w40 in summer and 10w30 in winter.

- 1st number indicate Cold temperature : The larger the number the heavier the viscosity (thicker, resist frozen)

2nd number is indicate for Hot temperature operation

Notes: you DO NOT have to change different type of oil in the summer vs winter, that is the thing of the past, it does NOT apply to your multi-grade oils (ie 10-W-30, 10-W-40, 5-W-30 ) Unless you live in extreme place like Alaska or something.
If you don't already know, ie 5W30 meaning it range of operation is the same as all the oil in the range 5W to 30W.


See all the recommendation and info here:
http://www.api.org/programs_services...y/oilguide.pdf
Guide to SAE Grades of Motor Oil for Passenger Cars
Typical SAE Viscosity Grades for Passenger Cars

Pick the oil depend on the place you live, you can see 5W30 cover all the normal ranges.

If lowest expected outdoor temperature is:
0°C (32°F) 5W-30, 10W-30, 10W-40, 20W-50
–18°C (0°F) 5W-30, 10W-30, 10W-40
Below –18°C (0°F) 5W-30



Multigrade oils such as SAE 5W-30 and 10W-30 are widely used because, under all but extremely hot or cold conditions, they
are thin enough for easy cranking at low temperatures and thick enough to perform satisfactorily at high temperatures.
Note that your vehicle’s requirements may vary. Follow your vehicle manufacturer’s recommendations on SAE oil viscosity.


I personally switch back and forth between 0W30 and 5W30 Full Synthetic oil, just because 0W30 oil can flow a lot faster than 5W30==> reduce engine wear during start UP. Beside, synthetic oil are SUPERIOR to conventional oil in duralibility and vicosity rate, does not really matter if you use 5W30 or 10W30 synthetic, same thing, even 0W30, did you see the operational range of them? they pretty much cover all the temperature here in Texas

Funny, I just had this conversation over the weekend. My book says 5W30 but I always use 10W30. The thinner oil is good for early morning low temperature starts, but living in Cali we never see severe temp changes (unless in the mountains or desert). I think the 5w in winter and the 10w in summer is the best bet.

so since i'm gonna be changing oil 10w-40 is wrong. so i should try and return it and get a box of 10w-30??

i live in southern california.

Jmai22
 

10-40 is fine, use 5-30 next time, 10-40 ie range from 10 to 40
10-30==range from 10 to 30, see the range, 10-40 has a wider range then 10-30

I use 5w30, it is the softest. 10w30 is too rough on the engine.
I can feel the difference. Want smoothe -go 5w30

I use Amsoil 0-30. Since the the first number is cold weather start then I figured the lower the better. Correct me if I am wrong but at running temperature 0-30 should be the same as 10-30. Actually I got use to the 0-30 when living in San Diego for 13 years. I re located to Atlanta last July(2011).

I just got back from getting the oil changed. Precision Tune owner say 20-50 is best. I use to run that in my BMW and Mercedes before that but I don't think that would work to well for my LS 400(2000 MY).

John

10 years old post

Stock GS400, 110K miles, Castrol Edge synthetic 5W-30. Car does not burn a drop between changes

Simple, just use manufacter recommends, 5w-30

Come on guys so many threads on this topic.... Bumping a 10yr old post?