Itry to use redline whenever possible. Back from the racing days I found that Redline dissipates heat much faster than even Amsoil, based on an electronic oil temperature gueage. Having said that Amsoil is a great oil and that is what I run in abscence of Redline. Both have 15-40 available.

 

CRX:

10W-30 is acceptable according to your owner's manual. Check the temp range. As long as the oil meets whatever spec (for my 2002, the minimum is CH-4), then you can use it. Note that the Rotella 10W-30 is CI-4 rated. But NOT CI-4+!! Part of the CI-4+ spec is a viscosity that puts it thicker than a 10w-30. The oil for CI-4 PLUS must be thicker because of the higher oil temps associated with the cooled EGR and other emissions measures that the PLUS spec was developed around.

Most everyone knows that most engine wear occurs at startup. Why? Simply put, the oil is too thick, and piston tolerances are too high (too cold). Oils are designed to function at operating temp, usually 180-220 degrees. Note that oil is much thinner at these temps than during a cold start.

It's possible that a lighter oil allows more wear at higher temps. But I accept that trade off for MUCH faster pressure rise, and better oil performance when the engine is warming up. Like they say: dress for the crash, not for the ride. Since like 90% of wear occurs at startup, I "dress for the crash" by using a lighter oil that STILL meets all the specs required for my engine.

In my usage, I have a lot of short trips and cold starts, so a lighter oil is much more appropriate. If you do a lot of hwy driving or towing, then a heavier oil would be more appropriate. The point of my post was just that lighter oils protect better when max wear is occuring, and good enough when up to temp. These engines have 1) lots of bearing area, and 2) high oil pressure-- BOTH of which indicate that a thick oil is not necessary.

I've actually considered a 0W-20 wt oil, just to see how it worked! Generally, if you have good oil pressure, you have thick enough oil.

Rotella in 10w-30 is PERFECT imo for these trucks.

Redline in 10w-30 is my favorite of all possible CTD oils. I just hesistate at $30/gallon

 

So why chance damage with a 0W20 when you can run a 0W40 that gives the benefits of both worlds? 0W viscosity when cold and 40W when hot? Besides the 0W40, 5W40 is probably cheaper than 0W20, the only vehicles I know that run 0W20 are Ford and Honda and I don't think those are rated at CI4? Just cause you have oil pressure at a certain temp doesn't mean that the oil isn't experiencing thermal breakdown. oil pressure is only part of the problem, if there isn't enough lubricating properties, detergent properties, anti-foamong properties etc then the oil isn't going to be working properly and can damage other parts in the engine. Again if you are comfortable doing this in your expensive truck fine...but in my truck I want to ensure it lasts as long as possible and am more comfortable using viscosities that cover all the demands I put my truck through. And in my owners manual there is no reference at all to any 30W oil. It even recommends 5W40 for cold climates (-15°C) and the only other recommendation is 15W40. And yes you are correct about the CI4+, however have you seen how much soot the new 600 series motor leaves in the oil...trust me the + is a good idea! In the end it comes down to personal preference I guess.

 

Amsoil front to rear in everything I own including a New Holland tractor.15w40 engine oil in my truck with a once a year or every 12k oil change and a filter at 6 months and top off.Fixing to call Amsoil tech line and inquire about the NEW suggestions of their Donaldson oil filters with NO change at 6 months and talk about now their suggesting oil every 25k or once a year.

 

I use Royal Purple 15w40 CI-4+ and have in all my diesels, with great results. I live in a hot area and pull 12,500# I need the added protection the syn oils give.

 

Flyinhigh79,

I am running Amsoil 15W-40 in my truck down in hot, humid South Texas and towing a large boat. Note that most of the guys recommneding the "lighter" oils are in Canada and the northern states where the temperatures are lower. Keep in mind your environment and the type of work you do with your truck.
I purchase in large quantites, a 30 gallon drum direct from a Amsoil jobber in Dallas, TX, Ches Cain. He gives me great service and a good price. I think my last drum was equilavent $5.35/qt. Running synthetics in all my vehicles and been very happy.

L8r,............dogger

 

Dogger, this is my point...it is a common misconception a 0W40 is too light when hot. This is wrong. When tested at higher temps for viscosity it still retains a 40W rating, same as a 15W40 or even a straight 40W, it is no thinner when run in extreme temps. However the main benefit is that at subzero temps it will infact have a viscosity of a 0W which is obviously better than 15W when trying to get oil flowing to bearings, cams and other vital parts quicker. Same is true about a 5W40. I am not saying there is anything wrong with 15W40 just that if the price isn't more then there should be no reason to not use the oil with the wider range. In fact I run Mobil1 0W40 in my race car that sees extreme temps (even worse than my truck) and the motors have been standing up even better then when I used to run 15W50 and with cooler operating temps as a result. If you can get ahold of a viscosity chart for any particular oil of interest compare what viscosities at what temps between a 5W40 and a 15W40 and see what the differences are at higher temps, bet you would be surprised as to how well that 'thin' oil can perform. And again if you can get 15W40 cheaper and it won't be run in sub-zero temps then why not, sub-zero temps was the initial reason I switched to 0W40 but after researching the oil and seeing the the thermal stability and viscosity at higher temps I decided to run it all the time. I do also tow in relatively hot conditions occasionally (110°F) and am not concerned at all that the oil cannot keep up in the extreme temps. But again it all comes down to personal preference.

 

I use 5W40 Mobil 1 Truck & SUV as a blend in the truck, 1 gal with 2 gal of Delvac 1300, am using it 100% in an older Taurus, will start it using it 100% in the other Taurus, and will probably go 100% in the truck for the winter. I get it for $4 a qt at a local store when it's on sale, or you can get it for the same price in 5qt jugs at wally world. It's very, very similar to Delvac 1, both being excellent oils.

 

Well, all that I have seen has led me to believe that the first number in an oil spec is RELATIVE to the second number.

So, a 0W-40 is NOT the same cold thickness as a 0W-20. Allow me illustrate with info from Redline oil, for different viscosities of their oil.

SAE------>5W20--->5W30--->5W40--->10W30--->10W40--->15W40--->15W50
V@100°C>9.1----->10.9----->15.1----->10.7------>14.6------->14.5------>19.6
V@ 40°C >55------>67------->94-------->70-------->98--------->97--------->138


Sorry for the format, it's hard to make it appear properly. Anyway, note the *interesting* viscosities of different grades. Of note:
-- 10W30 is MUCH thinner when cold than a 5W40 (70 vs 94)
-- 15W40 is thinner when cold than the 10W40 (97 vs 98)
-- 5W30 is much thinner when cold than a 5W40 (67 vs 94)

So we can see that ALL 10W and ALL 5W are NOT THE SAME!!

This phenomenon is NOT unique to Redline oils. Let's looks at some data on Mobil 1:

SAE:----->5w20---->0w30---->5w30---->10W30---->5W40 (T&SUV)->10W40
V@100-->8.8------->10.3----->11.3------>10.0------->14.8-------------->14.2
V@ 40°->48.3------>56------->64.8------>62---------->102-------------->91.07

Well look at that! The 5W30 is THICKER when cold than the 10W30 is! The 5W40 is THICKER than the 10W40 when cold as well! The 10W30 is THINNER than the 5W40 when cold! 5W20 is THINNER than a 0W30!

So, we can see CLEARLY that a 0W is not always thinner than a 5W or 10W or 15W when cold. It's not even consistent within grades (for example, why is M1 5W30 than a 10W30-- both when hot AND when cold???).

The bottom line is that the specs on the front of the bottle tell you VERY little about the actual viscosity of the oil at the standard temps of 40°C and 100°C.

LOOK AT THE SPECS! Don't just go by the "rating". You can verify the data above at www.redlineoil.com and www.mobil1.com

Oddly enough , Redline 15W40 is thinner when cold than M1 T&SUV in a 5W40 grade.

 

What about Rotella synthetic 5w-40???? I'm running straight rotella until I hit 20K only have about 3K in less than three weeks!!!

 

Definitly interesting info. Does the viscosity ratings go any lower than 40°C by chance? I wonder if the viscosities get closer to what they are supposed to be at say 0°C (32°F)? Anyways great read and yes I agree check the specs...but don't forget about warranty issues for those of us still in warranty. I still wonder what DC would have to say about an engine failure when using 5W20 oil? My opinion is it is still not really worth the chance of the cost of a new motor. Out of curiosity have you found a 5W20 that is CI rated? The attached site has the specs for Esso XD3 oils, good read also.

http://www.esso.ca/Canada-English/Fi...Xd-3_extra.pdf

 

I wasn't referring to trying a 20wt in my truck-- my Nissan car is what I had in mind. The truck needs a 30wt minimum, imo.

There are no 20wt oils CI rated AFAIK. They won't pass the wear tests.

I wonder if the viscosities would change at a colder temp?

Would be expect a 5W30 that's thicker than a 10w30 at the tested temps to thicken more slowly as it gets REALLY cold, to the point where the 5W30 is thinner, like we would expect??

I dunno. I'm gonna surf the API site to see if I can find out.

jlh

 

Ah, now I see where the 5W20 comes in....