ugly oil analysis using CK-4

[Killer223]

Agreed! I will as well when my stash of 5/40 runs out in about 6 years. 3 if I go straight 5/40.

 

[Tuesdak]

Phoenix!! you live down south? no need to run 5/40.. IMHO. it is depressing to see the iron go up, but in my trucks i run 15/40. well. 50/50 in one, and straight 15/40 in the other.

THIS!!! 5W is too thin to run in this extreme heat period. It never gets cold enough here to be a benefit.

I have trouble with 15w-40 as it is, towing, 121 degrees extreme summer heat and setting off low oil pressure alarms. Combine this with going out of grade from oil overheating. Synthetic is better, but, the polymers that increase the viscosity have a limited life and are hurt by extreme heat.

Looking through my samples I see a spike in iron related to a replacement turbo, towing, and an engine rebuild. IMO stay away from 5w anything here, check the turbo to see if the compressor is rubbing the housing due to bearing wear, and pull a sample at 3000 miles to see what is going on. (Oil change not needed just a sample.)

I would see if they can run a soot number on that sample for you as my samples do have this. Soot is useful for another reason oil is going out of grade too thick aside of overheating, bad tune smoking too much, ring seal or EGR failure (proving gapless rings are better in a dirty IDI engine)...

 

[Killer223]

I really think I'd try a straight grade for one run, I have a few friends that live down in phx, they both run straight grade oil.
Me being in Flag I have to use the 15/40 as it gets cold.

 

[TWebster]

ck-4 is most likely cleaning up the engine internals and that why the increase in FE.

 

[AH64ID]

I have trouble with 15w-40 as it is, towing, 121 degrees extreme summer heat and setting off low oil pressure alarms. Combine this with going out of grade from oil overheating. Synthetic is better, but, the polymers that increase the viscosity have a limited life and are hurt by extreme heat.

:--) Woah! I hope the alarm went off at idle, but that's still not good. The low oil pressure alarm trips below 6 psi for 30 seconds. The min pressure at idle is 10. I'd be concerned more about what causes the low pressure than 121° heat.

Ive seen idle pressure as low as 15 (on the hot side off the block, not the oil filter head) in the 110's and high coolant temps. And it was back around 20 within 30 seconds of idling. Below 6 psi for 30 seconds is concerning if it wasn't false.


Synthetics do handle the extreme temps better. In the hot climates 15w-40 is fine but 5w-40 shouldn't matter. When they are both hot the viscosity is the same. If the ambient temp is hot enough a 5w-40 isn't going to be much thinner than a 15w, and they both get up to temp quick. There are more synthetic 5w-40's than 15w-40's out there and, IMHO, a synthetic 5w-40 is better in hot climates than a dino 15w-40. A synthetic 15w-40 is my preferred oil thou.

I just looked at some Amsoil specs and CK 5w-40 is slightly (15.2 vs 15.0) thicker at 100° than the CI 15w-40 I run. There should be zero concerns running that oil in high ambient temps.

The Valvoline Premium Blue 5w-40 CK oil has a 100° viscosity rating of 15.3. Its fine in hot ambient temps too.


Edit: just saw your comment on soot. It's on the black stone report as insolubles.

 

[GrantP]

I currently have the first batch of CK running in my '07. I'll grab a sample next month when I change it to compare. I'm guessing I'm not going to be happy with the results.

Please let us know, I'm trying to figure out if there is a trend here.

 

[GrantP]

Phoenix!! you live down south? no need to run 5/40.. IMHO. it is depressing to see the iron go up, but in my trucks i run 15/40. well. 50/50 in one, and straight 15/40 in the other.

I agree there is no "need". But the synthetic was on sale so I thought I would give it a try. I also travel a lot through the rockies so temperatures are certainly going to vary. I'll be up your way tomorrow. When the truck leaves the garage it's generally heading north...weekend trips to Flag are routine and a couple to Whitefish MT every year.