5w30 /10W30 seasonal ?

[zking67]

I am curious about this one ... my car uses 5w30 synth. year round , my dad says use 5-30 winter /10-30 summer ,dealer uses bulk Castrol GTX 5w30 for 0CI I will be doing 4 month OCIs should I flop around with seasonal viscosities? am I harming the engines? or should stick to 5W30 Pennzoil Platinum ( I know PP is overkill for short OCIs but for 7$ more for an OCI VS Pennzoil conventional Ill take the PP)

What are your thoughts on this?

my dad does not want to use synthetic after 40K miles on 2008 pontiac SV6 so I guess 3K/3mos for him old school!says engine will leak oil . BTW his first car ... in 1953 was a 1948 ford Prefect ( 2 cyl.) sort of like a PT cruiser


BTW i buy my oil in US what you guys pay for synthetic thats pretty much the price for Dino maybe 1.75c more per qt , so no brainer there.

 

[Quattro Pete]

The views seem to be divided on this one, but I personally do not see a valid reason for alternating oil grades due to seasons. A 5w30 oil will protect your engine as well as 10w30 during summer, but a 5w30 will offer slightly better startup properties during winter, so using 5w30 year round is a no-brainer to me.

 

[tig1]

I switched between straight 20WT Valvoline in the winter to 30wt in the summer back in the early 60s into the 70s. Thats old school stuff. Use the wt. the engine is designed for and use it year round.

 

[HTSS_TR]

If most of your winter trips are less than 10-12 miles (15-20 km) I would go with xW20 in winter and 5W30 in summer.

 

[bepperb]

Look at the specs of Mobil 1 5w30 and 10-30 and tell me where they are significantly different... I can't tell.

Engine won't leak oil on syn, but if he's only willing to go 3000 miles he might as well stay on conventional.

 

[dgee]

I'd just use 5w30 year round.
PYB for short OCI's. No need to dish out more for syn

 

[Old Mustang Guy]

When I got my first car in 1970 many people didn't trust multi-weight oils of that era and used straight 30wt year round in our Texas climate. I went with 10W40 which was becoming very popular. I'm a 5W20 guy on my Fords now.

 

[rick9009]

My 2001 mazda protege and 2003 hyundia elantra spec 5w30 only up to 90 degrees. So they require 10w30 in the summer. Above 105 the elantra requires 5w40 or thicker. Before just taking advice on here check your owners manual.

 

[Eddie]

Follow the owners manual

 

[SrDriver]

Last 4 vehicles here have recommended 5W20 year around. That is what we have used without issue and we have long hot summers here. Today it will be near 100 degrees.

 

[scurvy]

Seasonal viscosities are silly. 5w30 and 10w30 are the same viscosity at operating temperature, but the 5w30 will flow better at low temps - use it year 'round without worry.

Both my cars get 5w40 and have had no problems going from -17F in Chicago to +107F in Baltimore.

 

[J. A. Rizzo]

I would follow whatever the manual says and don't worry about it. Change it according to the maintenance schedule and use whatever API spec oil the manufacturer recommends. If PP does it for you, great. If Pop changes 3 mo./3k mi., you already know you can probably discount most of his thoughts on the matter.

Originally Posted By: zking67
BTW his first car ... in 1953 was a 1948 ford Prefect ( 2 cyl.) sort of like a PT cruiser


Before this statement, I thought Ford Prefect was just a character in Hitchhiker's Guide to the Galaxy. One trip to Wikipedia cleared that up. You learn something every day.

 

[dwendt44]

Being in Canada, 5w30 year round will be fine.

My 2¢

 

[OilNerd]

Originally Posted By: scurvy
Seasonal viscosities are silly. 5w30 and 10w30 are the same viscosity at operating temperature, but the 5w30 will flow better at low temps - use it year 'round without worry


+1.

Always good to see Montrealers on the forum.

 

[dparm]

Only time I would change for the summer would be to something like 15w40 from a 0w40/5w40.

The difference between 5w40 and 10w40 isn't very great.

 

[webfors]

It's up to you. Put it this way, there's no benefit *not* to use a 10w30 in the summer over a 5w30. It's more shear resistant and usually a great deal on sale

 

[coffee]

You could even consider MaxLife 5w20 or 5w30 for year round and get sealer and protection.

 

[hooligan24]

would there be reason to not use your owners manual recommendations if those recommendations were made back in the API SL or earlier days? AIn other words, Is there any significant changes between SL and SM/SN that would change the decade old recommendations?

 

[Nickdfresh]

With the advent of Group II, II+, and even II/III blends for "conventional oil," there's really little reason in switching grades and 5w30 will do fine year round where called for.

 

[znode]

Absolutely no need in switching to 10w30. You're getting more cold startup wear and less fuel economy, all for the hypothetical "more shear resistance," even though no modern 30wt oils with its high-quality basestocks under proper service intervals require "more shear resistance".

The only scenario in which I would do it is under an engine that is known (and not by anecdotal evidence either) to shear oil out of grade, not by dilution (which you can get rid of by a 15 min highway trip), within its service interval. That would unlikely to be any engine made in the last 10, or even 15 years.