dirty howie

If you add equal amounts of 10-30 wt oil with 20-50 would that be the same as a 15-40 wt oil ??????????


DH

JohnnyC

No, and the reasons why involve equations that I do not want to even think about getting into.

SHINER

iTrader: (18)

Do NOT ever mix oils!

dirty howie

Can you please tell me why????

The oil is synthetic and the same brand if that makes any difference.

Please enlighten me............!!!!!!!


DH

dirty howie

Is it ball park close or what?????

It would have to be thicker than 10 at the low range and less than 50 at the high end.....wouldn't it????


DH

delinquent543

bump, this is a good question lol.

ChocoTaco369

no, because they all have different properties. for example, mobil 1's 40 weight series is much better than its 30 weight series. you'll be mixing different additives, different base crude, possibly different groups (group I, group II, group III, group IV, group V), plus they all run at different CST's. it's nothing but a big mess. mixing oil is a BAD IDEA. PERIOD.

btw, why would anyone EVER want to run a 15W-40, especially in an LS1? can you say "no startup protection" and "never starts in the cold"?

staringback05

iTrader: (8)

WTF?~!.....who comes up with this crap?...choco handle this oil issue, just thinking about that gave me a headache....

thatd be like giving midgets stilts and telling them to post up jordan....that **** just aint gonna happen

dirty howie

So you recommend Mobil 10-40 (correct me if I'm wrong) but feel 15-40 is too thick???

Also I am in SoCal ...... so cold = 40* F

And this is a stroked 402 which is not really a factory LS1 in clearance specs.

And the builder recommeded 15-50 Mobil1


DH

dirty howie

Can you please translate this into an answer that is understandable


DH

SHINER

iTrader: (18)

I think you could get away with a 20W-50, especially if your living in sunny California!

dirty howie

I have been using Valvoline Syntec 20-50.

Then when the weather recently changed my oil consumption went up. I had a leakdown/compression test and all was good.

Tony at AFR suggested that a possible explanation would be (this is not his words) that some tilt in piston/rings could be sucking extra thick oil off cylinder walls.

Thanks for confirming that I am not a COMPLETE IMBACILE for using thicker oil


DH

dailydriver

If a builder specs an oil weight then I guess that's what you should use. The ONLY oil brand I would mix weights with (within brand only) is Red Line. Reason being, they are one of the few (only??) brand(s) that DO NOT add viscosity index improvers/pour point depressants to any of their oils except for their 5W-40. Otherwise, the additive package is IDENTICAL across their whole multi-viscosity range (I confirmed this with their techs). So mixing weights is OK with Red Line.

ChocoTaco369

i wouldn't recommend a 10W anything. there's no point in running a 10W in an LS1. all it does is starve the motor on startup. run a 5W or a 0W. the only oils i can honestly recommend are GC 0W-30 and mobil 1 5W-40. mobil 1 0W-40's okay, too. other than those three, i wouldn't put anything else in my engine. the last ~8,000 miles of my motor's life have been on GC 0W-30. i just switched to mobil 1 5W-40 for a comparison. i'll analyze both and run the better from here on out.

a 50 weight is far too thick IMO! i wouldn't want that clogging up my motor and causing huge oil pressure. i wouldn't run a 40 weight either if it's conventional oil. a 40 weight synthetic is fine because they seem to be thinner and have better flow properties. again, 5W or 0W is all you should run in these motors. 10W is too thick for startup and doesn't flow fast enough.

dirty howie

Thanks for your input....


DH

dirty howie

Thanks for your opinion and clarification .......


DH

ChocoTaco369

np

1999Transamman

iTrader: (18)

dirty howie

Refilled with Mobil1 15-50 as originally recommended by builder.

Doesn't seem like anyone makes a 15-40 synthetic?????.....you can get 0-30, 0-40, 5-20, 10-30, 10-40, 20-50, and even 5-50....but not 15-40

At least I know I can run the **** out my car saturday at WSIR


DH

dailydriver

Most of the synthetic 15W-40s are labelled as "diesel oils" with higher TBNs/detergents/additive packs, etc. Both Red Line and Amsoil make one,. I'm pretty sure there's a Rotella and a Delvac version as well.