Conventional 5w30 in Phoenix in the summer?

[dvancleve]

Howdy folks.

I have run full synthetic oils forever, since the late 80s anyway. It sounds like regular oil is a lot better than it used to be, and I am not driving my '97 Subaru Outback much (maybe not even 3K miles a year). I should probably be doing time based oil changes, so there won't be many miles on the oil. It seems like conventional would be fine. Do 5w30 non-synthetics hold up in high heat driving (say 110F+ for a few weeks straight) or should I stick with 10w30?

Thanks, Doug

 

[Smokefan1977]

Welcome to BITOG,

5-30 will work perfectly year round out here in conventional flavor. Pennzoil and Mobil Super 5000 are both great products. I persoanlly like the additive package of the Yellow Bottle SN oil

 

[oggb]

Just use 10w-30 year round. You'll probably never even notice the difference in gas mileage or anything else.

 

[Eddie]

I would use a good dino like PYB in a 5w30 and change once a year.

 

[Oregoonian]

Motorcraft 5w30 (Blend) would be my choice.... Its a great semi-syn.... and price-wise....about the same cost as a quality conventional (dino), such as PYB or Mobil Super 5000.

 

[Merkava_4]

10W-30 doesn't shear as much as 5W-30 and you don't need the cold flow ability in Arizona. Go with 10W-30.

 

[The motor guy]

Look at the owners manual.

 

[dvancleve]

It says 5w30 anywhere, 10w30 also listed for temps above 0degF... So does conventional 5w30 degrade faster than the same 10w30 under hot to very hot conditions?

Originally Posted By: motor_oil_madman
Look at the owners manual.

 

[Bamboooo]

7.5w-30

 

[aquariuscsm]

I`d go for the 10W30.

 

[Cristobal]

Go for the 10W-30 if you will be around Phoenix.

But if you plan to go in winter to Flagstaff or some places like Angel Fire and Eagle Nest use the 5W-30. These last two towns are in New Mexico and see lows of -25 or so pretty often in December or January.

 

[CharBaby]

Originally Posted By: dvancleve
It says 5w30 anywhere, 10w30 also listed for temps above 0degF... So does conventional 5w30 degrade faster than the same 10w30 under hot to very hot conditions?

Originally Posted By: motor_oil_madman
Look at the owners manual.


5W30's shear a bit more than 10W30's due to fuel dilution. Fuel dilution is due to many short trips, oh lets say, less than 10 miles. Many engine start ups and short trips time after time don't allow for the fuel in the oil to burn off. And I don't mean that fuel is getting "dumpped" into the oil, just "some" all the time when driving only short distances.

There is a bit more to it than just the difference between a 5W30 and a 10W30. It also has to do with the viscosiey index improvers(VII) and that 5W30's use more VII's than 10W30's in which the fuel dilutes the VII's more. Others can explain this better than I can.

Fuel in the oil is caused when the cold engine is started and the engine is running in it's richest mixture. And then when the engine is turned off after just running down the street(to the store or where ever), the fuel doesn't get burned off. And over the period of several months or a typicle oil chance interval(OCI), the oil such as a 5W30 "can" soon become a 5W20 as the fuel has thinned it out.

Although if your trips are longer or if you happen to get on the 101 periodicly then there isn't an issue when using a 5W30. I think you'll be fine using either 5W30/10W30 without any issues at all especially in Phoenix and with the new SN/GF-5 conventional motor oils.

Keep in mind that long(er) trips are always easier on the oil and the engine than short(er) trips. Getting the engine up to "operating tempuratures" (not outside temps) is the key.

 

[CharBaby]

I forgot to mention about moisture in the oil also.

 

[lexus114]

Originally Posted By: Cristobal
Go for the 10W-30 if you will be around Phoenix.

But if you plan to go in winter to Flagstaff or some places like Angel Fire and Eagle Nest use the 5W-30. These last two towns are in New Mexico and see lows of -25 or so pretty often in December or January.



2:37 AM? Man you guy`s are up late!

 

[CROWNVIC4LIFE]

Originally Posted By: Oregoonian
Motorcraft 5w30 (Blend) would be my choice.... Its a great semi-syn.... and price-wise....about the same cost as a quality conventional (dino), such as PYB or Mobil Super 5000.


I definitely agree with this!

 

[mechtech2]

dvan -
I am glad to see someone who learns and stays up with the times [oil wise].
'Dino' oils are very good to superb right now.
For the vehicle you mentioned, theh dino 5-30 will work great.

 

[dvancleve]

Thanks guys :^) I gotta say though, my takeaway so far is that 5w30 dino would be fine but sticking with the 10w30 I have always used might be (a tiny bit) better. I am think I'm going to try the Nextgen Maxlife 5qt jub with the rebate, still pondering which weight... Doug

 

[dvancleve]

Originally Posted By: dvancleve
Thanks guys :^) I gotta say though, my takeaway so far is that 5w30 dino would be fine but sticking with the 10w30 I have always used might be (a tiny bit) better. I am think I'm going to try the Nextgen Maxlife 5qt jub with the rebate, still pondering which weight... Doug


Not sure what happened, I was editing this but couldn't save the changes. Anyway, I just read most of the "Motor Oil University" stuff and now I am (once again) not sure. I didn't know that dino starts as the low number and has stuff added but synthetic starts at the high number. Clearly synthetics are better, but does it matter?

This car does mostly short trips and doesn't rack up many miles per year. I took that to mean the 10w30 might hold up better, but it is worse for startup. Probably any of the synthetic weights I have used over the years flow better than either 5w30 or 10w30 dino, so is startup my biggest concern? Also, this car leaks at least a bit. Is 5w30 going to exacerbate that, or does it matter?

Doug

 

[andrewg]

5w-30 Motorcraft Blend. Cover all the bases without costing an arm and a leg. Good for short trips, handles the heat well, flows good at start up, and will be fine for the OCI. If your car does leak a bit like you said....you may want to try a high mileage blend from Valvoline in a 10w-30.....or get the leak fixed.

 

[Smokefan1977]

In a long drain yes 10-30 wont shear as much but out here dont be scared to run a 5w oil. Put it this way, i have a friend that is the shop foreman for AAA Yellow Cab and the only oil they use is Formula Shell 5-30 with 6000k OCI. Every car they have on the road has 250K+++ miles on them. I do agree Motorcraft Syn Blend is a fabulous product, but for the OCI your planning Dino or syn blend will give you equal protection. It doesnt happen often but I know where I live ( south Gilbert ) last winter we did see some Lows in the teens. This is where i'd want 5w.

With that leak you may consider a High mileage oil. 10w and 5w will all leak the same. The difference is so very little. With the OCI you are planning you will not see any better protection from Dino to Syn. The major advantage to syn is the ability for extended drains. It always helps to once a week put that car on the freeway for a couple of miles. Motor oil isn't the only item that benefits from a good heat cycle