10w-40 too thick?
 

I recently did an oil change, and much to my dismay, i might have used the incorrect oil viscosity.

I meant to use 10w-30, but instead i used 10w-40.:egads:

My engine has 186,600 miles on it.

At idle, oil pressure is at 37psi.

I do run the car quite hard, and was wondering if this is going to be a problem.

Thanks in advance.

It shoudn't be a problem....your in california so im sure you car is seeing temps in the 90's.(especially if your saying u push the car a lot)

Is your car NA?

yea NA.

Its probably like 90+ today. lol

I believe the only problem might be a very minimal loss of hp like 1-2 bhp.

yeah its fine especially since ur at 180k miles.

i mean how long have u used 10w-30 for?

Probably for a while. Maybe the last 3 changes?

well just keep goin with the 30 then after this...ur car was running 5w30 im guessing since the last 3 changes so its still kinda fresh on the engine that ur using 10w...

then again ur engine isn't fresh at 180k miles so remember that...dont be concerned just drive it.

i use 20w50. You'll be fine

heres the perfect link for a good amount of good information regarding oil viscosity basics:

http://www.supramania.com/aehaas/

Since you are a 10w-40 your start up will be the same viscosity as a 10w-30 oil. It only thickens at higher operating temps.


Vinh:

"There is little advantage to a thicker based oil as a 20W-50 at very high temperatures. No, the 4 cS oil is not twice as thick as the 2 or 3 cS oil. This difference is almost insignificant.

There is a huge advantage of using the thinner, 10W-30 at startup where 90 percent of the engine wear occurs."

personally I would change it to an even thinner 0w-30 TRUE synthetic. Just so that there is even less wear on start up and it still acts as a 30 weight at op. temp.

mobil 1 0w-40 is what i use, best of both worlds

I want to go thinner, however I am starting to notice a little dripping :sad:

Rear main seal FTL.....

...you guys need to understand hes at 180k miles. Using synthetic now is like trying to stop smoking cigarettes after you already got diagnosed with cancer....

hes not even turbo...just let the car be at 10w30 where it is perfect for his engine.

lemmiwink your in texas idk how hot it gets there but here in so.cal this summer its been hitting the 100's every day almost. And if its not 100 degreess its like 95...same ****

especially since hes saying hes pushing his car all the time...in this heat pushing the car is a killer sometimes...imo.

try not to push it the way ur saying when ur A/C is on full blast in this heat..

What is your argument? Don't switch to synthetic because he's had dino oil all his life?

What, would you say, is the problem of switching to a synthetic at really any stage except for the break in stage of a motor?

Did you hear of how they may make seals leak? I admit that i've heard that they used to shrink seals, but that is now a thing of the past as their addative packs include things that swell seals. So now it actually helps it not leak.

Leaking seals means you should change it. Period.

Also what of the heat? Yes it is hot in Texas, but what of it? Op temps of an engine is near or over 200 degrees farenheight.

Relatively speaking, 100 degrees is still fairly cold and even then its the exterior temperature not the temperature of the engine itself. I doubt you will go inside, turn on your car, and your temp guage will already be above the bottom most line.

So your engine temp is still "cold" at startup even in Texas. Startup is still the phase where the most amount of wear occurs. Having a "thinner" viscosity on start up capable of increased flow will cut down on engine wear. Its not the pressure of the oil on engine parts that lubricates it. It is the flow.


Besides, at operating temperature 0w-30 IS THE SAME VISCOSITY as 10w-30.

Also a true full synthetic (group IV PAO, or group V ester based oil) will be able to carry and transfer heat very efficiently without degrading the oil itself . This is something dino oil can't brag about.

Hence, why the 3,000 mile oil change is now being pushed past 5,000 because old dino oil will degrade significantly by then. But true full synthetics are still holding their viscosity well over 5k miles.



I doubt that you will kill your car if you push it with the a/c on in the heat. It might not perform as well in hot temperatures and the parasitic draw of the ac compressor, but with an intact and healthy cooling system I believe you can get on it within reasonable limits. Pushing anything hard enough will get it to it's limits though regardless of outside weather. In that case an investment in supporting cooling mods (oil cooler) is a good idea.


OP: sorry to jack your thread. I will stop now and if somone wants to argue more I suggest making another thread specifically for that.

LOL this thread is vaguely familiar...:rolleyes: someone has been on supramania too much!!! jk

I've read this article too and i think it has some very vaulable aspects that have changed my look on motor oil. I'm still very hesitant about changing to synthetic on my 168k motor as i have seen first hand. Even though i believe that these additive packs will help, it still makes me paranoid as hell. I have dropped the viscosity from my usual 10w-30 to a 5w-30 and noticed that it is a little quieter at startup. If and when i do perform an engine swap i will definitly make the switch to a 0 weight oil though.

To the original post though: you should be fine to your next oil change, but next time get some 5w-30 dino oil and see if you notice a difference. If your as gutsy as lemmiewink here go for a zero weight motor oil like 0w-30 and see what happens.

thanks guys.

Car feels fine right now. I notice absolutely no difference.

And i never push the car with the AC on cold.

Its either off, or on MAX heat.