Dangers of 5W-40 in a car spec'd for 5W-20?

[Steve S]

 Originally Posted By: GMorg

xxch4osxx wrote: "what is your opinion on using a good quality synthetic straight 30 weight oil". I would bet that most any "straight 30 weight" would qualify as a multigrade. Does anyone sell a synthetic straight 30?

That is a rather bold statement !

 

[Nickdfresh]

 Originally Posted By: sprintman

In Australia you probably would run 5W40 in it.

Same thing in Europe I bet...5W-40 is probably spec'd for this engine in other parts, no worries...

 

[GMorg]

Steve S: Perhaps it is, but can you find an exception? The naturally high viscosity index of the synthetics typically found in base oils will generally put an SAE30 in at least the the 10W category.

 

[Jim 5]

Somewhere on this site there's a honda accord v6 UOA. That car is spec'd for 5w-20 and he got his best UOA yet on 5w-40. Cars that are spec'd for 5w-20 in north america are routinely spec'd for 5w-30 and 5w-40 elsewhere in the world. I wouldn't use a 5w-40 in a northern north american winter though.

 

[tdi-rick]

 Originally Posted By: GMorg

Steve S: Perhaps it is, but can you find an exception? The naturally high viscosity index of the synthetics typically found in base oils will generally put an SAE30 in at least the the 10W category.

Way back in the early nineties, Neo's SAE30HD actually met the 10W-30 spec, but they marketed it as a straight SAE30 as its target market was motor racing.

 

[BTLew81]

I'm REALLY thinking of running Rotella Syn in my 3. I've run GC in it, which is essentially a 40wt with NO change in MPG. It actually ran much more quietly as well.

 

[Johnny]

 Originally Posted By: ArcticCat

I've got the option to obtain some synthetic 5w-40 oil(VW 502 00/505 00 and Porsche approved) at a very low price. It would be used in a Mazda3 2.0 that is spec'd for 5w-20 and changed at 12,000km intervals (after the warranty period expires). Are there any downsides besides potential loss of fuel economy ? Anyone think there's any danger to the engine aside from possibly a couple MPG and a couple horsepower?

What brand of 5W-40 are we talking about here?

 

[ArcticCat]

It's Syntec 5W-40.

 

[Johnny]

That's a good oil.

 

[Tornado Red]

 Originally Posted By: Johnny

That's a good oil.

Syntec is an okay oil. It's not one of the top 5w40's.

 

[sprintman]

BP Visco 5000 5W40.

 

[G-MAN]

 Originally Posted By: GMorg

Amsoil ACD 10W30/SAE 30 qualifies as a multigrade. That is my point. It is difficult to find a synthetic SAE30 that does not meet the cold viscosity requirements of at least a 10W due to the high viscosity index.

True for conventionals, too, since these are being made with Group II base oil now. If tested as such, Valvoline straight 20 would qualify as a 10w20 and their straight 30 would qualify as a 20w30.

 

[BTLew81]

OP...thought of running M1 TDT, D1, or RTS?

 

[toyota62]

Castrol Magnatec C3 5w-40. ACEA A3/B3/B4/C3

 

[ArcticCat]

 Originally Posted By: BTLew81

OP...thought of running M1 TDT, D1, or RTS?

No, haven't ever really thought of running those. Anyway I didn't pull the trigger on the 5w-40 deal, so I'm still working on using up my stash of Mobil 1 5w-30, Q Horsepower 5w-30, and Castrol GTX 5w-30. I'm now leaning towards switching to GC when my stash runs out, but that won't be for a good 2 or 3 years, at which time who knows what bargains will be out there!

 

[lars11]

Should not be a problem. In Sweden it is speced to 4.3liters of 5w40 synthetic if it's a 110kW 2.0. 5w40... as most cars.

 

[BTLew81]

GC would be a FINE choice in this car. My engine really "liked" this oil. No drop in MPG, VERY quiet

 

[ArcticCat]

Ya, I actually have 2 OC's worth of 0w-30 GC and 1 OC worth of 10w-30 Penz Platinum in my stash, in addition to the 5w-30's listed above. So I've got enough in the old stash to run my Mazda3 for about 3.5 years. After this is all used up I'll be stocking-up on some more GC and/or some other Euro spec oil, but not until there are some good discounts available. I bought my GC at $6 Canadian per quart a while back, but I haven't seen it that cheap again since. So...I'll likely be replenishing my stash with GC when I see it for $7 or less a quart, unless some 'new and improved' Euro spec synthetic becomes available at this price.