Is 10w40 Dangerous?

[coffee]

I have seen people post negative things about 10w40 grade and want to get more feedback on this grade. Is there some reason people are negative about this grade or is it a good grade and safe to use?

 

[Merkava_4]

This ought to be a good one.

 

[ekpolk]

Old history. At one time (70s, early 80s IIRC), some car makers actually forbade the use of 10w-40 oils, apparently because the "primative" VIIs used then were so poor that they could not be expected to hold up through a normal OCI. As for now, I doubt that there are many engines that actually call for this grade (it was one of the authorized grades in my 04 G35, FWIW), and OTOH, I also doubt that the current versions are anything like the potentially weak oils from twenty years ago.

 

[BarkerMan]

It that a typo? Do you mean 0w-40?

 

[coffee]

I meant 10w40 because many people post about VII's or something like that and make it like it is a bad grade of oil. Personally I am interested in using it for my older Volvos if it is a good grade of oil.

 

[wavinwayne]

API SL & SM 10w40 conventional oils should not be 'dangerous' in any non-turbo, gas engine where an XXW30 or 10w40 oil is recommended.

 

[Merkava_4]

There are some that perceive 10W-40 as being an extremely thick oil that is sure to bog down your engine with fuel mileage robbing sluggishness; almost akin to pumping concrete through your engine.

 

[XS650]

Originally Posted By: Merkava_4
There are some that perceive 10W-40 as being an extremely thick oil that is sure to bog down your engine with fuel mileage robbing sluggishness; almost to the point of being akin to pumping concrete through your engine.

That's what happens to people who snort kerosene.

10W-40 got a somewhat deservedly bad wrap back in the olden daze when VI improvers and oils in general weren't what they are today.

 

[Merkava_4]

10W-40 is so thick that it will break the impellers of your oil pump off.

 

[kilgore68]

I have a 1992 Jeep Cherokee with Renault 2.1 L TD (Norway)
The manual says "Do not use 10w-40 oils,Use 10w30 or 15w40"
The engine was first made in the late 70`s or early 80`s
I have never understood why I should avoid 10w30.
Maybe bad oil from those years, is the explanation

 

[Merkava_4]

10W-40 is so thick that it takes 20 minutes to reach the top of your engine on start-up; in the mean time, your engine is running dry with no oil flow.

 

[Merkava_4]

10W-40 will shear back to a 30 weight in 500 miles and leave broken strands of plastic viscosity index improvers floating around in your engine. What else can I come up with?

 

[coffee]

Merkava, you are killing me!! I was laughing out loud at home! Thanks for those posts. I may go with the 10w40 for my Volvos.

 

[Gary Allan]

Quote:
What else can I come up with?



You'll shoot your eye out, kid!

 

[Pablo]

It is twue back when we rubbed our rocks together for heat....er...in 1970 or something, for 10W rated Group 1 base oil to achieve 13+ or so cSt @ 100°C it would take a lot of VII's, more specific polymeric thickeners....and in the olden crusty days some of these just did not hold up too well, and result in some nasty sludge. Never a worry with synthetic oil and now even with Grp II+ oils, and much better VII's.

 

[Audi Junkie]

I use it in Euro cars and oil burners.

 

[sprintman]

In the UOA section there's a very very good UOA with 10W40. it was posted a long time ago. If 10W40 is dangerous what would you call 40W70??

 

[flatlandtacoma]

It may be dangerous if you drink it...

 

[paulo57509]

I like putting 10w-40 in my shopping cart because it makes me appear VERY dangerous. I'm downright scary because I buy Pennzoil 10w-40.

 

[coffee]

hehe, well I am glad I was misinformed and can feel confident using it. Thank you all for the input.