Thin vs Heavier Observations/Questions

[OriginHacker21]

I've been running Amsoil ASL 5w30 in my car for two oil changes (3-4k each). Having run GC 0w30 for 30k miles before I dumped Amsoil in there I noticed that my car's engine (140 hp 2.2L Ecotec 2004 Sunfire) rev'ed a lot easier with Amsoil. I also noticed with Amsoil that downshifting was a lot easier because the engine was more willing to go in the higher rpms.

Well a few days ago I put GC 0w30 back into my engine (mainly because I have a huge stash of GC that I want to use up). I noticed that the idle was a bit more rough (vibration) and the exhaust sounded more throaty but the engine was far more quiet in noise output (in front). I noticed how the engine seemed reluctant to past 3,000 rpms unlike with Amsoil which felt free up to 6k. When downshifting I have to leave the clutch in longer because the engine doesn't rev up as willingly.
I have driven almost 400 miles with GC 0w30 now and have only noticed a -1 to -2 MPG difference (getting 37MPG instead of 38-39MPG like I did with Amsoil) along with an overall heavier engine feel.

Upon startup - Amsoil ASL 5w30 was smooth as dream. Engine was a bit louder (noise only) once warmed up and it loved to rev in the 3-5k range.

Upon Startup with GC 0w30 the engine clicks and clacks (lifters?) for a good 30 seconds (when it is 40F outside) till the engine warms up to about 100F. Then the engine is very sluggish till it hits full temperature. Overall - the engine is quieter/smoother but doesn't want to go past 3k rpms. I notice that there are more engine vibrations with GC0w30 than with Amsoil (in the gas pedal on takeoff).


SO my question is this: Which oil is preferable? Is GC going to be detrimental to the smaller engine in the long run due to more stress/engine load? I've run GC with great used oil analysis for 30k miles before and just recently seen the effect of a lighter oil (Amsoil ASL). Lighter oil makes the car seem like it lost 500 pounds.

P.S. I have ScanGuage which I monitor consistently (engine load, MPG, Engine temperature, and air intake temp). I drive 220 miles a day to/from work.


Questions/comments/similar experiences? Yes, I know I'm splitting hairs but thats what BITOG is about right?

Thanks all, - Paul

 

[carock]

I NEVER say that these things do not actually happen, but there is no engineering service that has ever found that switching between excellent oils, like the ones you mention could make such a big difference.Particularly with fuel economy.Nonetheless, if it works, stay with it. Every discovery is made by observations made just like yours, then the testing and instrumentation begins.

 

[Merkava_4]

Jee, the way you're describing GC, you'd think you were talking about a straight 50 weight.

 

[OriginHacker21]

There probably isn't a huge amount of difference - but there is enough to notice a difference nonetheless.

I guess I'll have to wait for a used oil analysis on the GC and Amsoil to compare the weight (cst).

 

[Titan]

When you make statements about exhaust sounding more throaty with one oil, it makes me think your other observations may be similarly affected by your biases. Come, on...really? A few Centistokes difference changes theh exhaust note? I simply don't believe this is true. Certainly you do not provide enough information to make a determination that GC is perhaps going to be "...detrimental due to more stress/engine load."

You may get better fuel economy, and may indeed have a more responsive throttle response from small engines with thinner oils. That sounds much more reasonable!

 

[hominid7]

My car certainly notices the difference between something like Castrol GTX 10w30 and Superflo 5w30. True they are both rated as being the same (viscosity) at 100*C, but my guess is that my car rarely sees 100*F. So while operating in the 'cooler zone' of 70-90*C i'm sure my car picks up a couple of HP, and also produces a noticably different audible sound. My car also idles absolutly silent and vibration free with 5w30, with 10w30 it's really smooth, but you can detect a few rumbles now and again.

Is one better than the other? Likely not so much that it would make a difference in the life of the car. However if you are getting lifter tick with one oil at startup, regardless of viscosity, i'd try something else.

My guess is you could save a bunch of $$ and run Motorcraft 5w30 in that engine and have the best of both worlds.

 

[OriginHacker21]

Yeah, I think you guys are right. I have it in my mind that GC 0w30 is "much" thicker than Amsoil when in reality there is little difference. Thanks for that info Titan - I believe you are right.

hominid7 - That sounds *very* familiar to what I am experiencing.

I did a search and GC is thicker at 100 CST (12.3) vs Amsoil 100 CST (10.6).
CST @ 40 - 67 for GC 0w30.
CST @ 40 - 55.8 for Amsoil 5w30.

CST values for Amsoil taken off of Amsoil's site and GC's CST values taken from: BOBPage

Check out that page - talks a lot about viscosity and whether or not you can "feel" it.

Notice how much "thicker" GC is than Amsoil at startup. That might be causing the lifter clicking.

427Z06 reported some different GC viscosities on that BOBPage link (close to the bottom of the page)
CST 40 - 69.0
CST 100 - 12.1

 

[Merkava_4]

We're going with all CAPS for CST now? I thought it was supposed to be little 'c', big 'S', and then little 't'. (cSt) If we're going to all CAPS, that would certainly be easier.

 

[hominid7]

My Mazda gets some clacking at startup in temps below freezing with the old Havoline 10w30 and Castrol GTX 10w30. None with Pennzoil, Superflo, or Motorcraft 10w30, and none with any 5w30 i've ever tried.

For the record i've never used any full synthetic and dont plan to anytime soon. I dont mean to turn this into a thin vs thick debate, nor a dino vs synthetic debate, but i still cant justify the cost of synthetics relative to the benefits i would see in the environment my car operates in and my OCI, granted your environemnt may be much different.

GC may flow at temps far below where a regular 5w30 conventional would, and likewise be less prone to shear under very hot temps or in racing or towing conditions in the outback, but that does not necessarily mean it is not still thicker at say 15*F than a traditional conventional or synthetic blend 5w30, not does it mean it will protect your engine any better at normal operating temps in realtive normal temps like we see in Dallas, KC, Denver, NYC, etc... So unless you are operating your car in extreme temperatures or racing, GC while not hurting your car, may be creating more drag and thus creating more friction and less power than perhaps a traditional 5w30 would and thus be seen as a worse oil for your particular engine in your environment. Keep in mind i'm saying this in theory, i have no direct experience with the 2.2 Liter Ecotec engine.

Despite the fact it was 80*F yesterday here, last week it was 12*F one morning (Crazy Texas weather for ya). After slipping and busting my rear on the ice, i made it to my car, curious as to how it would sound at start-up with the Pennzoil conventional 10w30 oil i had in the crankcase. It cranked up with zero hesitation and zero clacking or any complaints whatsoever.

I continue to go back and forth in my mind regarding 5w30 and 10w30. If one was significantly worse than the other in my particular situation, my choice would be easier.

 

[hominid7]

Quote:

---

When you make statements about exhaust sounding more throaty with one oil, it makes me think your other observations may be similarly affected by your biases. Come, on...really? A few Centistokes difference changes theh exhaust note? I simply don't believe this is true. Certainly you do not provide enough information to make a determination that GC is perhaps going to be "...detrimental due to more stress/engine load."

You may get better fuel economy, and may indeed have a more responsive throttle response from small engines with thinner oils. That sounds much more reasonable!

---

There is no doubt in my mind that i can hear a difference between certain oils. Now my question is, what exactly am i hearing? Is it the fact heavier oils make the actual internal engine quieter and i can thus hear the injector clicking more? Or does a thicker oil make the friction gear noise more noticable (which is a problem in my particular engine design)? There is a difference in my car, of that i have no doubt. However i would be willing to debate on exactly what i'm hearing, or not hearing.

 

[todds21]

I recently put GC 0w30 in my wife's ES330. It previously was running Mobil 1 Extended Performance 5w30. The car does seem quieter on cold startup with the GC but does seem a little more sluggish...I am writing this off to a thicker oil. In Dallas the thicker oil I think will be a benefit as its in the 70's this week and will be in the 100's for months solid before long.

 

[williar]

This goes to show that one needs to use an oil that's appropriate for the vehicle. No oil, including GC, is appropriate for all applications.

 

[OriginHacker21]

Hominid7 said:

Quote:

---

There is no doubt in my mind that i can hear a difference between certain oils. Now my question is, what exactly am i hearing? Is it the fact heavier oils make the actual internal engine quieter and i can thus hear the injector clicking more? Or does a thicker oil make the friction gear noise more noticable (which is a problem in my particular engine design)? There is a difference in my car, of that i have no doubt. However i would be willing to debate on exactly what i'm hearing, or not hearing.

---

100% agree with you there. I can definitely tell the sound difference of GC 0w30 and Amsoil 5w30 in my engine.

It would be interesting to get an expert in here to explain what we are hearing and what this means for the engine.

Above posters are correct: one oil does not fit all. I am very convinced that you have to find an oil that your engine likes for optimum operation. Very interesting indeed.

 

[Titan]

May be a different sound. Doubt it is related to the exhaust "note". I've heard the valve train noise change on a couple of Honda engines I had depending on the oil used...but, mostly at relatively low rpms.

 

[Laminar Lou]

The weight of the oil is not the whole story. Friction modifiers play a role in how smoothly the engine revs too. I've got Amsoil 0W30 in the Tundra and it likes it a lot. I've noted a consistent increase in MPG as well. So much that it will pay for the cost of the oil over the life of the oil change (I project about $80 in savings over 1 year/6K miles).

OriginHacker,

The Series2K oil is pretty expensive, but when I switched from the Amsoil XL 5W30 to the series2K 0W30 I noticed a marked improvement. Not only does the cold idle pressure get to normal faster during warmup, but the WOT smoothness has been improved.

Might be worth a shot.

 

[sprintman]

What will your exhaust note sound like with 40W70?

 

[OriginHacker21]

I believe that the posters here are correct - the noise is not the exhaust but rather the engine itself. I made an incorrect assumption linking the noise with the exhaust but it was instead the engine itself - as Titan said - at low RPMS/idle.

 

[427Z06]

Quote:

---

Yeah, I think you guys are right. I have it in my mind that GC 0w30 is "much" thicker than Amsoil when in reality there is little difference. Thanks for that info Titan - I believe you are right.

hominid7 - That sounds *very* familiar to what I am experiencing.

I did a search and GC is thicker at 100 CST (12.3) vs Amsoil 100 CST (10.6).
CST @ 40 - 67 for GC 0w30.
CST @ 40 - 55.8 for Amsoil 5w30.

---

Don't forget the HTHS and FMs between the two.

Whether all this is perceived or some kind of placebo effect, I'll just add that my experience with differences like this depend heavily on the engine involved. Generally, in new, tight, smaller Japanese engines it's highly pronounced. In an older 7M-GE or bigger American V8, not really noticeable. YMMV.

 

[buster]

I've always found it depends on the engine and HT/HS of the oil. GC made my Accord sluggish. Amsoil runs great (5w30). So do all the 5w-20's.

Too bad Castrol doesn't use the GC chemistry for all the Syntec oils. Castrol, are you listening?