Will 5w-30 hurt my engine

[01sapphirebob]

I asked this befor but I could'nt find the thread. Will driving with the 5w-30 oil hurt the engine?

[Vman455]

I'm going to guess at Tom F&L GoR's response here: no. The first number (5W) indicates the oil's viscosity at cold temperatures; it's still a 30 weight at normal operating temperature.

Of course, Tom will also probably say you're better off using a 15W-40 mineral or 5W-40 synthetic diesel oil...do I get a prize if I'm right?

[plumcrazy]

what he said but wait for tom to give the exact reason.

[Tom, F&L GoR]

Originally Posted by Vman455

I'm going to guess at Tom F&L GoR's response here: no. The first number (5W) indicates the oil's viscosity at cold temperatures; it's still a 30 weight at normal operating temperature.

Of course, Tom will also probably say you're better off using a 15W-40 mineral or 5W-40 synthetic diesel oil...do I get a prize if I'm right?

Correct!
5W-30 is OK, 15W-40 and 5W-40 have more to offer.

The 5W30 is a US-centric viscosity grade and won't have many (any?) Euro performance specifications. It is the "good" product of good-better-best choices. Fine for "normal car" use but I'd go to the next choices if there is track time involved.

[Schulmann]

If you have a cold thermostat, it is better to run 5w-40 or 5w-30 in the North.
In Canada 5w-30 is the way to go in the spring. 5w50 is an engin killer during cold weather.
5W-50 will cause valve floating above 5500rpm.

My engin hardly gets upto 160F because I have a cold thermostate.
It is not very good because the oil doesn't get enough hot to remove acides and water vapor.

I also use a thinner tranny oil so the shifting is easier.

[Stretch]

Originally Posted by Tom, F&L GoR

Correct!
5W-30 is OK, 15W-40 and 5W-40 have more to offer.

The 5W30 is a US-centric viscosity grade and won't have many (any?) Euro performance specifications. It is the "good" product of good-better-best choices. Fine for "normal car" use but I'd go to the next choices if there is track time involved.

I don't have it in front of me, but I thought the service manual for my 95 said to use 10W-30. That hasn't been mentioned at all in the thread so far, is it wrong?

Is 5W-30 a better choice all around? That would actually be awesome b/c my dd is that weight so I would only have to buy one kind at the store.

[Tom, F&L GoR]

Originally Posted by Stretch

I don't have it in front of me, but I thought the service manual for my 95 said to use 10W-30. That hasn't been mentioned at all in the thread so far, is it wrong?

Is 5W-30 a better choice all around? That would actually be awesome b/c my dd is that weight so I would only have to buy one kind at the store.

We'll get into the formulation now...

As stated, a xxW-30 is a xxW-30 is a xxW-30. The "30" is not an actual measurement, it just means that the oil is between 9.3 cSt and 12.5 cSt at 100C.

Oils are formulated by starting with the low temperature properties. Therefore a 5W-30 is perhaps a 4 cSt unadditized oil until viscosity modifiers (thickeners) are blended in. This makes the thin oil at low temperatures behave like a thick oil at higher temperatures. A 10W-30 would start at maybe 5 cSt and add less VMs to reach the "30" window.

At very high shear (think "smear") rates the VMs can elongate or align with the direction of shear and depending on the chemistry, produce a little more or a little less thickening power. So people argue about whether a 5W-30 with more VM would shear more and provide less thickening when engine parts really need it.

The reality is that the chemistry of the VM determines shear down, and consumers can't tell what they buy. The "30" is a window, so you don't know if the oil is at the thick end or the thin end. The API specifications are clear, so no oil can be below the techical minimum. Therefore any arguement is moot, since any oil is meeting the spec and there aren't any facts available to say how much better than the minimum the oil is.

So strictly speaking of viscosity - a 5W30 gives equal or better performance than a 10W30 in regards to starting, pumping, and hydrodynamic bearing protection.

Why do I mention 15W-40 and 5W-40 oils?

If you follow the viscosity explanation, then the 5W-40 should be obvious. You get the same low temperature and pumpability performance, plus added insurance when the oil gets really hot or if you are a track rat. Notice I said more insurance, not more performance.

Those two viscosity grades are popular diesel engine oils. Diesel engine oils have 2X to 3X the additives and that adds anti-wear, deposit control, dispersancy, and extended drain. A 5W-30 is usually only a passenger car oil, so would be the 1X additive treat rate. A 10W-30 is frequently specified for light duty trucks, so probably is a 1.25X additive treat. The secret to longevity is never extend the oil drain past what the oil additives can last. So a 5W-30 is fine, as long as you change the oil when needed. (When needed is a whole different story. Let's just compare the different oils for now.)

Back to the 15W-40... it is the most popular diesel oil grade, available at Walmart, not expensive, but extremely robust. If you don't start your engine at 5F or below, then the 15W is fine. I use a 15W-40 year round and I am in upstate NY (near Tator Dodge.)

The 5W-xx and 10W-xx are designated passenger car oils and meet emissions system control protection and fuel economy requirements. Therefore Dodge would be hard pressed not to recommend using them. I have not looked at the 0W-40 Mobil 1 bottle, but I suspect it meets the fuel economy requirement that the 15W-40 would not be able to.

[Billy Coons]

$hit!!! I just put 0W-30 Mobile 1 Syn in mine...am I in trouble now?

[01sapphirebob]

Thanks everyone for the respnoses!!!!

[Tom, F&L GoR]

Originally Posted by Billy Coons

$hit!!! I just put 0W-30 Mobile 1 Syn in mine...am I in trouble now?

Of course not. Re-read the homework assignment above...

the 0W-yy gives you excellent pumping at low temperatures.
the xxW-30 provides good hydrodynamic bearing service, same as 5W-30 and 10W-30
the 0W-30 I believe has some Euro credentials (ACEA) so it has more additives.

it's a good choice.

[ViperTony]

Hey Tom, I was at Tator's last week picking up some fluids and Chuck informed me that Chrysler switched away from Mobil over to Pennzoil. How do you feel about Pennzoil?

[Billy Coons]

Originally Posted by Tom, F&L GoR

Of course not. Re-read the homework assignment above...

the 0W-yy gives you excellent pumping at low temperatures.
the xxW-30 provides good hydrodynamic bearing service, same as 5W-30 and 10W-30
the 0W-30 I believe has some Euro credentials (ACEA) so it has more additives.

it's a good choice.

Thanks Tom!

[Tom, F&L GoR]

Originally Posted by ViperTony

Hey Tom, I was at Tator's last week picking up some fluids and Chuck informed me that Chrysler switched away from Mobil over to Pennzoil. How do you feel about Pennzoil?

Pennzoil and Quaker State and Shell are all brands of oil marketed by Shell US. In the late 1990's, Shell and Texaco had a joint venture that forced many Texaco lubricant formulators to go to Houston (I jumped ship into fuels at the time and stayed in NY.) So basically my long-lost ex co-workers are formulating those oils today. They are a good bunch and if you look at some of the "tuner" oils that Quaker is coming out with (like the odd viscosity grades, I think there is a 2.5W-30 that isn't even an SAE category) it tells me the technical and marketing folks are working well together.

Hey, the marketing guy at Quaker that challenged the other oil marketers to an engine test for wear protection could not have done so with out the technical folks' saying it was OK. I think Quaker (i.e. mother Shell) was calling out the others on their goofy "pick a single category out the many to say we're great" claims and they were right - nobody took their offer of a free engine test.

I like the view that they are still differentiating between the brands they carry. Shell is huge in the US and likely gets good price discounts on their purchases. I think they will do fine.

Mobil is also a great brand. They led the mass consumer into synthetics (no matter what Mr. Amatuzio says) and their marketing has support racing, OEMs, and performance enthusiasts also. However, as ExMo is selling all their branded gasoline stations they will be dropping out of marketing fuels themselves. That becomes an interesting scenario since it may affect Mobil oil sales at the stations (i.e. either don't have to carry Mobil 1 or may carry other brands besides Mobil oil at a Mobil station.) It also means any cross advertising of Mobil oil with ExMo fuels is going away. Could be tougher sledding for the Mobil oil brand.

[Stretch]

Originally Posted by Tom, F&L GoR

So strictly speaking of viscosity - a 5W30 gives equal or better performance than a 10W30 in regards to starting, pumping, and hydrodynamic bearing protection.

Tom, thank you very much for the information. In the future I will use the 5W-30 in the Viper to make it more convenient to be buying the same oil as my daily driver.

[alpine7822]

Tom, with the switch from Mobil to Pennzoil, and, as you predicted above, a possibility of trouble for Mobil oils...as long as we continue to use synthetics, can you switch brands (i.e. - Mobil to Castrol or Pennzoil) without any issues?

[Tom, F&L GoR]

Originally Posted by alpine7822

Tom, with the switch from Mobil to Pennzoil, and, as you predicted above, a possibility of trouble for Mobil oils...as long as we continue to use synthetics, can you switch brands (i.e. - Mobil to Castrol or Pennzoil) without any issues?

Please don't read too much into my Mobil comments. That's just an old, ex-formulator talking.

You can always switch brands; mineral to synthetic and reverse. Part of the oil development program is to test for general compatibility.

The only thing not to do is a 50%-50% mix of two oils, even same brand. A 5W-30 and a 10W-30 both from Mobil don't necessarily have the same additive package. The problem with mixing additive packages is that some additives only work at 100% effectiveness at 100% of the dose. They work at 40% effectiveness at 50% of the dose. You may have two oils, each contributing 50% additive, but resulting in only 80% of the performance.

And before anyone panics, when you change your oil the amount left behind is not enough to worry about. Don't go double flush your oil, a simple change is fine.

[Jerome Sparich]

What would be a "better" choice between these 2. All things being equal.

Shell syn or Rotella T?

[Tom, F&L GoR]

You didn't say, but I assume you mean Rotella T synthetic. If so, simply pick the cheaper one. You can't believe how overformulated these oils are for passenger car (Viper) use and so the size of the sledgehammer doesn't matter.

[Darbgnik]

Hey Tom,

I have a hard time finding 0w40 mobil here so I grabbed 15w50. You mentioned higher performance oils had higher protection, I think, so I was wondering if this particular formulation would have more or the same amount of additives. And what your thoughts of this particular formulation are.
Thanks

[Jerome Sparich]

Originally Posted by Tom, F&L GoR

You didn't say, but I assume you mean Rotella T synthetic. If so, simply pick the cheaper one. You can't believe how overformulated these oils are for passenger car (Viper) use and so the size of the sledgehammer doesn't matter.

The Rotella is non-syn.

I am switching over from M1 in my truck and my beater to Shell syn. I will use the Rotella non-syn if it is "better" for me.

The Syn cost is $25 per case of 6 and the Rotella is like $28 per 12 qts (3-one gallon containers).

The truck gets 3k oil changes and the beater gets a once-a-year-needed-or-not change. That is anywhere from 7-12k miles.

Thanks Tom

[rcl4668]

Here's how the SRT engineers responded to my similar question:

Originally Posted by rcl4668
One other quick question: In the Summer 2008 Viper magazine article "From street legal to track regal," author Matt Bejnarowicz on page 15 recommends "[f]ill[ing] the engine with Mobil 1 15w-50 for extra protection under higher stress conditions * * *" in the 2008-2009 ACRs.

I have a 2008 Viper convertible that I take to approximately 8 to 10 HPDE events/driving schools per year (not races or timed events). The events are typically single day track events with 4-6 run sessions lasting from 20 minutes to an hour per sessionwith 15 min - 40 min breaks in between sessions. The track events account for about a third of the vehicles' usage with the remainder being normal street driving. I am in the Pacific Northwest where temps are typically fairly mild (no lower than 20 degrees generaly in the winter and no more than 100 usually in the summer).

Would my engine (which is stock internally) enjoy extra protection using the 15w-50 Mobil 1 as opposed ot the factory fill 0w-40 Mobil 1 I have used exclusively thus far? Would there be any disadvantage or risks performance or wear protectionwise to using the 15w-50? Would it be adviseable to use the 15w-50 during the track/HPDE "season" (April through October) and then switch back to 0w-40 for the remainder of the year?

Engine oil is a frequently-debated issue on this (and other) forums and I wanted your expert opinion. Thanks for your help.

/Rich

If you are at the track, zinging the motor at high rpm for extended periods, like your HPDE events, you will get extra protection from the viscosity of 15W-50. On the other side, 20F is about the lowest you want to do cold starts with that thick of oil. Even at higher cold start temps, like 50F and below, you should let the 15W-50 oil warm up before you start loading the engine hard. So, as usual, it comes down to your useage, driving habits, and expectations, which is why there is no right answer.

If you want the best of both worlds, run the 15W50 during the track season, and 0w-40 the rest of the time.