5 OR 10 W 30 Oil for 3.4 DOHC

[Paul GTP]

Which Oil is better for the application (not weather releated)

I just read article about motor oils on http://www.60degreev6.com

It says that 10W30 Oils are much better than 5W30 for the car engines

[Robby1870]

I have always used 10W-30 in my 3.1L. Dont know about a DOHC, but I think it should be the same.

 

Robby

[Redfox340]

5W-30 in my DOHC.

 

Stated on my oil cap and in the owners manual.

 

- RedFox340

[96montyZ34]

GM service manual says 10w30 recommended for dohc.

[STR]

GM service manual says 10w30 recommended for dohc.

 

sorry, oil cap says 5w30

[Brian P]

5W30 shouldnt be in any engines with more than 50k, use 10W30. 5W30 helps fuel economy by a micro number and thats why GM uses it. Ive been using 10W30 for 120k. Use it and you will see any small oil leaks and consumption disappear. Screw the friggin oil cap, no pun intended.

[stlunatics2oo3]

my cap and manual all say 5 w 30

but i am using 10 w 30 and i think it runs smoother with the 10 so just my 2 cents but brian is right

[Jeorge]

My cap says to use 10-30 but I dont have a Dohc,

 

I would say 5-30 in the winter and if you also read your manual it should state for summer 10-30 is fine. and it also askes what type of driving you do....atleast every GM owners manual I have Read says that

 

except mine it states only 10-30 because of the turbo...

[GnatGoSplat]

I used 5W30 up to 190k on my 89 Cutlass and never had a problem.

For the past 2 years I've been using 10W30 in the summer and 5W30 in the winter. Still no problems.

 

The manual states 10W30 is fine in the summer, so that's what I'd use.

The reason 10W30 is better: Less viscosity improvers.

The base oil viscosity of 5W30 is 5, of 10W30 is 10. It just takes more viscosity improvers to make 5W effective as a 30-weight.

 

Either way, it's no big deal. However, 10W30 is not recommended in climates that go below 0-degrees so if you're expecting some negative temperatures, stick to 5W30.

[gimp19]

I've used 5w30 ever since I bought my car but I'm also switching to 10w30 for spring and summer. Mainly because I know that it protects much better in hot temps then 5w30 and I want my car to go over the 200k mark

[RedZMonte]

For the past 2 years I've been using 10W30 in the summer and 5W30 in the winter. Still no problems.

 

Thats exactly what i do. thicker oil during the hot summers and thinner oil during the cooler winters.

 

RedZ

[SmokesGTP]

Yeah I pretty much stick to 10w-30 on my DOHC. On a car with 130k what difference is 5w-30 gonna make? not much, besides making it leak more. Anyone use the high mileage stuff by pennzoil or valvoline or any others? I use the pennzoil and its good shit, stopped the little bit of smoke I used to get in the morning.

[JS91Z34]

I use 15W-40 in my DOHC.

[Cutty Hertz]

10w40 for me!

[ismellrealbad]

10w40 in mah 3100

[GnatGoSplat]

There's more Viscosity Improvers in 10W40 which is why it's never a recommended oil. Acceptable, but not recommended. It's more likely to promote sludging in the engine.

[Cutty Hertz]

10w40 for me!

[Baddflash]

After or around 200k I've always switched my oil to 10w30. It gets real cold in Canada so 5w30 for winter. My Buick Century with 3.8L got over 250K with not one problem ran great, very quick.I got over 350K on my Cutlass with 2.8L MPFI never touched the block or heads it had a bit of blow-by but never smoked out the back.Currently my Lumina's 3.1L has just turned 253K and runs awesome. No blow-by, no oil burning, not even a leak.

 

Although in my opinion the 3.4L should have always had 10w30 and you should probably use synthetic; although switching can possibly create leaks, possibly!!! The Twin-Dual is a very complex motor a puts a lot of stress on all the systems of the car, it is not one that takes well to neglect. Routine maintenance is the key with these motors; I've seen many trashed by 100k very sad to see cause these engines rock.

[slick]

5w30 for mine.

[Bolt_Crank]

10W30 year round.... there's a reason us Canadians have block heaters

[Go4DaMo]

Correct me if I'm wrong:  the "5" in 5W-30 is crank weight.  As the engine warms up to operating temp, it becomes "30" weight.

 

Just put 0W-30 synthetic in my LQ1 DOHC.  It's original equipment oil from Toro for their snowblowers.  So, it's high zinc.

 

Planning to run it in below freezing temperatures.  It sounds happy the first 20 miles.

[Schurkey]

6 hours ago, Go4DaMo said:

Correct me if I'm wrong:  the "5" in 5W-30 is crank weight.  As the engine warms up to operating temp, it becomes "30" weight.

 

Just put 0W-30 synthetic in my LQ1 DOHC.  It's original equipment oil from Toro for their snowblowers.  So, it's high zinc.

5W-30 is as thin as a 5 weight at 0 degrees F.  It's as thin as a 30 weight at 212 degrees F.

As opposed to stuff you don't see much of--5-30 with no "W".  "5" weight at 32 degrees, 30 weight at 212.

 

Have you checked the zinc level of the Toro oil?  First Guess:  It's whatever they could source in custom-printed packaging cheaply, that's not a bit different from mass-market oil.  Given the weak valve springs and hardened followers of the LQ1, "high zinc" is not on my list of priorities.

[LokiZ34]

I have been using 5w40 since my 96 z34 3.4 DOHC hit 160k miles and it's now at 256k miles with no issues other then transmissions don't like my car

I use rotella t6 5w40 and have since I switched from 10w30  high mileage Valvoline and always  used the wix xp oil filter