Which oil to use

[Jimbob]

Hey all

So I live in Brisbane Australia about to do a oil change do you think I should stick with 10w-40 or go 10w-50 or even 20w-50?

I ask because it never gets that cold here but in summer can be up to 40°C

[Big Rich]

Here ya go:

http://wiki.gstwins.com/index.php?n=Maintenance.ChangeOil

Stick with the grade Suzuki recommends.

[fetor56]

This is a decent quality,and as we all know.......oils ain't oils.
http://www.supercheapauto.com.au/online-store/products/Castrol-Activ-4T-Motorcycle-Oil-15W-50-4-Litre.aspx?pid=20019#Recommendations

[Jimbob]

So 15-50 is okay?

If suzuki recommend 10W-40 is there any downside going 10W-50? Doesnt that just mean the oil will work at an even higher temperature?

[gsatterw]

It also means it will be thicker at lower temperatures, I believe.

[gsJack]

So 15-50 is okay?

If suzuki recommend 10W-40 is there any downside going 10W-50? Doesnt that just mean the oil will work at an even higher temperature?

My opinion on engine oil grade based on over 400k miles of riding air cooled  bikes year around here in NE Ohio, the last 180k miles on my 97 and 02 GS500s:

Use 10w-40 or 15w-40 unless you have a high oil consumption problem and really need the 20w-50.  I put 15W-50 Mobil 1 synthetic in my 97 GS for about 45k miles after breaking it in on 10W-40 dino for 5k miles and when oil consumption increased I switched to the cheaper 15W-40 Rotella T for the next 30k miles.  I used the 15W-40 Rotella T in my 02 GS for all it's 100k miles.  Engine wear due to miles seems to have progressed about the same on both bikes regardless of oil type.

My 97 GS progressed from regular to mid grade to premium gasoline to prevent gas knock in hot weather as the miles and carbon built up same as the 4 Hondas I used 20W-50 in summers did previous to the GSs.

When I switched from the 15W-50 to the 15W-40 in the 97 I went back to regular gas year round without gas knock and have used regular gas all my 100k miles on the 02 also w/o knock.

The GSs run cooler on a xxW-40 oil than on a xxW-50 oil and your doing it no favor using the heavier oil in hot weather unless oil consumption is real bad.  Besides lubricating the engine the oil also provides cooling by carrying heat away from the head to the sump.  This cooling flow is reduced with the heavier oils.

[twocool]

Go by the Suzuki manual....

Use 10W - 40....  That is "good" for temperature range of -20C to "over" +40C



only if that oil is unavailable, should you substitute...

10W - 50 covers the exact same temperature range....(-20C to "over +40C)

15W oils are for less cold....(-15C)....

Since it doesn't get that cold where you live it doesn't matter....

As Jack says below...thicker (50) oil is not necessarily "better"...may cause engine to run hotter!  Also, thicker oils can make starting harder, and allow slightly more engine wear until warmed up...

Use 10W - 40...common, easy to get, low cost, works for the entire ambient temperature range...puts your mind at ease...be happy...worry about more important stuff..

Cookie

Hey all

So I live in Brisbane Australia about to do a oil change do you think I should stick with 10w-40 or go 10w-50 or even 20w-50?

I ask because it never gets that cold here but in summer can be up to 40°C

[Atesz792]

Since you're in Australia I'd say run the thickest you can get away with, GS's like to sip oil, especially in hot weather & at high RPM.
Of course 10w-40 will suit your needs, but keep an eye on the dipstick, it might disappear quickly.

[Jimbob]

Ok Thanks guys

[fakejimmymorgan]

Hi JimBob, you've probably done the oil thing now but living in South Aussie I use penrite 10w40 diesel oil (with a little motorbike picture on the front of the bottle) because my ute and my bike could share and save me a few bucks.  Plus its decent oil.  Next change I'll switch to Penrith HPR5 synthetic 5w30 because all the vehicles can use the same oil then.
Jimmy

[user11235813]

I'm in Brisvegas and I've been using Fuchs Silkolene Comp 4 15W-50 it's a fully synthetic $60 and after my last oil change yesterday it was still in pretty good condition.

[Janx101]

Still using valvoline 15/40 diesel oil with the motorcycle rating

Brand is not important though.. most important is bike rated and NO friction modifiers!

[Jimbob]

So cars oil can be used in motorcycles as well as long as it doesnt have friction modifiers?

[Suzuki Stevo]

Unless you ride in extreme cold, 15w-40 is a good choice, the farther the two numbers are the more Polymers are in the oil. 15w-40 has less Polymers added to it than 10w-40...I just added this as a Fun Fact you can add to your bag of tricks in the next oil thread 

http://micapeak.com/info/oiled.html

"Multi viscosity oils are one of the great improvements in oils, but they should be chosen wisely. Always use a multi grade with the narrowest span of viscosity that is appropriate for the temperatures you are going to encounter. In the winter base your decision on the lowest temperature you will encounter, in the summer, the highest temperature you expect. The polymers can shear and burn forming deposits that can cause ring sticking and other problems. 10W-40 and 5W-30 require a lot of polymers(synthetics excluded) to achieve that range. This has caused problems in diesel engines, but fewer polymers are better for all engines. The wide viscosity range oils, in general, are more prone to viscosity and thermal breakdown due to the high polymer content. It is the oil that lubricates, not the additives. Oils that can do their job with the fewest additives are the best."



Go Hawks!

[Rallyfan]

The chart does show something "odd" though: according to the chart there is no reason not to use 20W year-round since it is unlikely the rider will use the bike below -10C.

Yet the other day I topped off my 15W-40 Rotella at +10C and it was syrup.

This is where a good synth 15W-50 (eg, M1?) could come in since I believe it's more pumpable at low temps than Rotella (check specs first).

Yet Suzuki sees no worries at -10C with a 15W.

[twocool]

Suzuki recommends 10W 40 for ALL conditions....

They say you may use others "if 10W 40 is not available"

Oil that is too thick can be an issue in cold...hard starting...less lubrication until it warms up...15W would not be my choice if 10W 40 is available (and it is)

Cookie

The chart does show something "odd" though: according to the chart there is no reason not to use 20W year-round since it is unlikely the rider will use the bike below -10C.

Yet the other day I topped off my 15W-40 Rotella at +10C and it was syrup.

This is where a good synth 15W-50 (eg, M1?) could come in since I believe it's more pumpable at low temps than Rotella (check specs first).

Yet Suzuki sees no worries at -10C with a 15W.