Using Heavier Weight Oil

[csaxon]

"Are there any problems with using a heavier weight oil like 10W50, 20W50, 5W50, 10W40"

I had written Mercedes with the same question for my SL. The letter sent to me from Ellen Bie of Mercedes was "our engineers recommend using the heaviest oil for the driving conditions". She then listed about 10 or more tested and recommended oils.

I don't know but I think these recommendations for american cars are more about getting MPG and marketing the better mpg, than about engine longevity.

 

[AndyH]

csaxon: No offense meant, but oil recommendations for a Mercedes (or really any German automobile, which tend to thrive on thicker oils) doesn't really apply to a Honda Civic.

 

[DaveInLA]

It does seem that newer engines like lighter oil, maybe for fuel economy reasons.

But my 1989 BMW recommends 20w-50, and so that's what I used before I switched to M1 15w-50. Some people used 10w-30, and most people on the E30 message boards said it was too light.

 

[hominid7]

Cogito: My old VW Jetta needed 20w50 year round here in Texas. Not necessarily for "engine protection" but because the engine mgmt system required a very high oil pressure. Otherwise the oil pressure warning lights would go crazy and the cars temp would get pretty hot. Keep in mind though, this was an 8 valve 4 cyl engine.

I think the newer German cars are more in-line with thinner recommendations, but the older ones seem to do well on 15w40 - 20w50.

 

[Cogito]

Why would German cars work any better with heavier oils than Japanese cars?

 

[Cogito]

The last day or two I've been thinking about the advice I've received in this thread, and reading up on Auto-RX. I remember one time that my oxygen sensor went out and the engine ran real hot (the cat converter was red hot). I probably scorched some oil and left some crud deposits in the engine from that incident that need to be cleaned out. So I think it makes sense to try out the A-RX treatment to see if it may reduce my oil consumption. Since I seem to be using a quart roughly every 700 miles or so, should I just add an extra 2 oz. of A-RX when I add a quart of oil?

 

[CoyoteMan]

I've noticed everyone talking about using 0W-30 oils. My impression is those oils were intended for temperatures in the -30 F. range to allow a much easier startup.

Just exactly what is the advantage of using 0W-30 motor oil in a standard climate where the night time temps never go below 10 F. degrees?

 

[ColdCranker]

CoyoteMan, The "0w" can be good, but you are right in that, if the temperature is above 0 degF, your probably better off with M1 5w-30 than German Castrol 0w-30 down to 0 degF or so. M1 5w-30 flows better at around 0 degF. The following table from member name 427Z06 shows:


code:
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TEMP * M1 0W-40 * GC 0W-30 * M1 0W-30 * M1 5W-30 * M1 10W-30 * M1 0W-20 * RL 5W-20-20 * 2661.5 * 2609.0 * 1994.8 * 2225.1 * 3424.8 * 1712.7 * 2995.8-10 * 1197.8 * 1127.1 * 872.4 * 944.7 * 1332.9 * 730.8 * 1165.30 * 599.3 * 546.6 * 428.3 * 452.9 * 595.7 * 352.8 * 521.410 * 327.6 * 291.8 * 231.3 * 240.1 * 298.3 * 188.5 * 261.820 * 192.9 * 168.8 * 135.3 * 138.3 * 164.1 * 109.5 * 144.530 * 121.0 * 104.4 * 84.6 * 85.5 * 97.6 * 68.3 * 86.340 * 80.0 * 68.4 * 56.0 * 56.0 * 62.0 * 45.1 * 55.050 * 55.4 * 47.0 * 38.8 * 38.5 * 41.6 * 31.3 * 37.060 * 39.8 * 33.7 * 28.1 * 27.7 * 29.2 * 22.6 * 26.170 * 29.7 * 25.0 * 21.0 * 20.6 * 21.4 * 17.0 * 19.280 * 22.7 * 19.1 * 16.2 * 15.8 * 16.1 * 13.1 * 14.590 * 17.8 * 15.0 * 12.8 * 12.4 * 12.5 * 10.4 * 11.3100 * 14.3 * 12.0 * 10.3 * 10.0 * 10.0 * 8.4 * 9.1110 * 11.7 * 9.8 * 8.5 * 8.2 * 8.1 * 6.9 * 7.4120 * 9.8 * 8.2 * 7.1 * 6.9 * 6.7 * 5.8 * 6.1130 * 8.2 * 6.9 * 6.0 * 5.8 * 5.7 * 5.0 * 5.2140 * 7.0 * 5.9 * 5.2 * 5.0 * 4.9 * 4.3 * 4.4150 * 6.1 * 5.1 * 4.5 * 4.3 * 4.2 * 3.7 * 3.9

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quote:
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GC qualifies as a 0W-30 multigrade, per the SAE J300 viscosity chart, at 2 temperature extremes.

It is a 0W since it is less than 6200 cP at -35C and it meets the SAE 30 100C requirements at 100C.

No specifications exist as to what the temperature/viscosity curve does between these two temperatures.

The GC 0w-30 vs. M1 5W-30 viscosity anomaly exists due to the fact that GC is 12 cSt@100C and M1 5W-30 is 10.5 cSt.

Since both have high VI indexes(which is really the slope or rate of change of the temperature/viscosity curve), both are getting thicker at similar rates as the temperatures get colder.

It simply takes GC awhile to catch up to the M1 5W-30 & pass it up and be thinner on the way to the -35C final temp!

 

[ColdCranker]

OK, the above chart is not readable. My bad. I tried copy/paste. It can be found at viscosity comparison thread discussion URL :

 

[ColdCranker]

Remember, in the table, the temperatures are Celsius!

 

[Cogito]

So, anybody? Should I add 2 oz of A-Rx when adding a quart of replacement oil before the 3K OC?

 

[RandyBarnett]

Use the recomended amount of AutoRX for the amount of oil in the engine.

 

[sprintman]

Anybody using less than 40W70 is a wuss!!

 

[Titan]

IF "clearances" are larger than they were when the car was new, it means wear has occured. If a car gets "used to" heavier oil by increasing "clearances", it means using heavier oil resulted in increased wear. Which, I think is possible, as a slow-to-flow heavy oil in something like a Honda Civic engine might cause more start-up wear than if the engine would have had the correct thinner oil in it.

I like your response, Sprintman! Oil viscosity isn't a contest...use the thinnest recommended oil that works well in your application. Your "clearances" will thank you...especially at start-up.

 

[bar1]

Titan, Honda recommends oils in a span from 0W-30, 5W-30, to 10W-40 (maybe 50) for those engines in other markets than NA (even places that has more or less equal climate as NA).
In fact the warranty would be void here if I (found and) used a 0W20 (or 5W-20) oil in a Honda engine. Going one step up in SAE grade isn't going to hurt any Honda engine, but mpg might be worse.

 

[shokhead]

Maybe someone should explain what the 5 and the 30 means in oil. I would but it would really be confusing. LOL

 

[radiometer]

When I bought two new Honda Civic LXs in December, the dealer service department told me that my using a XW-30 in them is not a warranty issue. I have GC in the one I drive and my engine just loves it. I'm getting a much less cold engine noise and the idle is smoother at all times.

My wife asked when I'm going to do that with the one she drives.

It is not bogging down my engine as some have reported in their experiences. It is as responsive as with the factory fill.

I'm watching MPG carefully and at this point I see no significant difference even though I'm needing to run the AC in our quite warm winter. I won't tolerate poor MPG and that is why I'm paying close attention to this.

I've paid attention to the message at the top of the main page of this forum that states, "Your Engine Is Talking! Are You Listening?" Oh, you bet I'm listening and my engine is very happy.

 

[427Z06]

Here's a picture of the translation, since that URL is posted incorrectly. Notice it doesn't say anything about thicker oils providing any additional protection. And the 0w20 is just as good as a 5w40 at high temperatures.

 

[Titan]

bar1, as I said, use as thin an oil as appropriate for YOUR application. If YOUR manual doesn't state it allows 0-20 or 5-20, don't use it if you are concerned about warranty problems. If you are out of warranty, perhaps you view that as a different set of rules, perhaps you don't.

I don't think running slightly thicker than needed oil is a big deal, either. I'm just not so hung up on the exact viscosity issue. Oils shear and/or change viscosity, so, we are just looking at ranges anyway. I wish GC 0-30 was a bit thinner. Doesn't keep me from running it, but, I'd prefer a thinner 30 weight than the almost-40 GC.

 

[GMorg]

Thanks 427Z06,

That label really just says to not use 10W-30 if ambient temp is below -20 C. I don't see how a label warning about how an oil can be too thick supports any comments about "thick" being better. Apparently, Honda does think that 40 weight is acceptable - not necessarily preferred...