Just the idea of being many, many km beyond Alice Springs and overheating !!
VVT and thicker oil
- Thread starter Scott S
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I'd have to agree the article isn't entirely correct.
If it was, then every start in cold temperatures would result in multiple codes and a poor running engine - which is not the case.
I have personally run 40 grade oils in vehicles specifying 20 grade in the US, with absolutely zero issues.
[insert CAFE discussion here]
Overseas manuals/specifications do not list only 0w20...it is a spread, based on temperature much like US manuals used to be.
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Really, why is that?
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If you are to fill an engine with 0W20, but only drive it in the summer, then you should take a look at this calculation: 0W20 has 202 mm2/s at 0C. 0W40 has 270 mm2/s at 10C. So if I start my vehicle exclusively above 10C, I can drive a 0W40 without hesitation.
Kestas
Staff member
I once changed the oil and put 20W-50 in a 1998 Escort ZX2 where 5W-30 was recommended. It immediately threw a VCT code. Swapped that oil for 5W-30 and all was good.
What was the code number?
Some Mopar vehicles can have this problem but that's a bad design IMO. I've actually sat and read the valve timing actual vs desired on my own vehicle which has dual variable valve timing and even on a cold engine running a 50 grade it's spot on. The closed loop/vvt operation kicks in as soon as the engine coolant temp reaches 32°f. There is absolutely no reason a computer controlled engine with cam position sensors and crank position sensors can't adjust to differences in oil viscosity and oil viscosity plays a small role in the first place. Solenoid controlled VVT operation is done via pulse width modulation of a valve that opens to hydraulically move the cam gear, the more VOLUME of oil in the gear the more retarded the timing, since oil flow in an engine is controlled by a positive displacement pump the only thing that would cause the timing to be unable to retard is a complete lack of oil due to either low oil or a vvt valve being stuck shut or slow to open.
Kestas
Staff member
I forget the number, but it was for the cam sensor.
Sure, under the force of gravity. There's a reason that a positive displacement oil pump is used to force oil through an engine to critical parts. The VVT is a system being fed by pressurized oil. They operate correctly above a certain oil pressure, so doubt that they would malfunction or set a check engine light if the oil pressure was higher than not.
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Why would you choose to drive one of the worst-driving dual-cab utes on sale here? They really are a POS to drive.
Good chart. Is all the hand wringing done at Bitog just a result of staring up an elephant’s butt? Differences between in kinematic viscosity at 100 C are “in the noise”. Oil is oil. Flame suit on.
I do not take this vehicle off road. It actually is perfect for my job as a delivery driver subcontractor.
Yesterday I made a time critical medical delivery, driving from San Jose to Sacramento and back 240 miles total. Everything is fine.
4WD
$50 site donor 2025
Bumped my Pentastar 0W20>5W30>0W40:
No change in oil PSI/°F
My Gen Coupe 2L the oil temp sensor is right before the intake CCV solenoid. That being said the engine came with 5w20 in it. The changed that to 5w30-60 depending on ambient temps around the world in a TSB the next year. I've used the 5w30, 5w40 and 0w30, 0w40 in it with no issues.
Only issue I ever really had was on an '04 CRV but that that had mediocre maintenance records. It had some conventional oil that was probably thicker. Could have been 5W-30, maybe even 10W-40 and was in for too long, about 7-8k. CEL came on for VVT issues and wouldn't go past about 2500 rpm.
Could have been multiple issues contributing, I changed oil with 5W-20 Syn and factory filter, cleared code and all was well. It stayed on that until the tranny went and it wasn't worth the $$ to repair with other vehicle concerns.
My '17 Accord 2.4 seems to lose some performance when cold on M1 0W-40 though really shouldn't. Total seat of pants measurement. Once warmed up no issues but seemed to burn a bit more during the OCI than I recall previous. It's on 5W-30 currently and cold performance feels better.
Cold on the Accord = about 3-4 minutes, winter or summer headed to firehouse in a more "spirited" drive with many stop signs. Under normal daily drive conditions harder to tell. My Accord is a 6MT so the engine rev, power area is noticeable for when I shift.
I like THIS video on the Honda variable Valve timing to show the oil channels, seals, spring etc. Helped me understand a lot better and thinking of sludge/varnish/viscosity etc. that others might have. Combine those issues with a weak spring and I can see issues happening. Other manufacturers are probably different with other solenoids.
Could have been multiple issues contributing, I changed oil with 5W-20 Syn and factory filter, cleared code and all was well. It stayed on that until the tranny went and it wasn't worth the $$ to repair with other vehicle concerns.
My '17 Accord 2.4 seems to lose some performance when cold on M1 0W-40 though really shouldn't. Total seat of pants measurement. Once warmed up no issues but seemed to burn a bit more during the OCI than I recall previous. It's on 5W-30 currently and cold performance feels better.
Cold on the Accord = about 3-4 minutes, winter or summer headed to firehouse in a more "spirited" drive with many stop signs. Under normal daily drive conditions harder to tell. My Accord is a 6MT so the engine rev, power area is noticeable for when I shift.
I like THIS video on the Honda variable Valve timing to show the oil channels, seals, spring etc. Helped me understand a lot better and thinking of sludge/varnish/viscosity etc. that others might have. Combine those issues with a weak spring and I can see issues happening. Other manufacturers are probably different with other solenoids.
It's "in the noise" when on a graph with those scales. The y-axis scale needs to be 0 to 20 cSt at at temps from 80 to 120C to see what's really going on. Many viscosity vs wear studies show that higher HTHS viscosity, which only varies 1 cP between "fhin vs thick" oils, can make a difference in keeping moving parts separated and a difference in wear.
Honda and Toyota, manufacturers of some of the most reliable long lasting engines on the planet have long abandoned HTHS concepts for their engines. Yep, foreign owners manuals may have different numbers but guess what. It doesn’t matter. Run what ever you want, as long as it shows up in someone’s manual. If a person wants to track a vehicle and has good idea of the elevated temperature, then you can pay attention to HTHS. The grade 0w20 has been around for over 20 years, and we still have all this hand wringing over it.
Might as well get those articles out and refresh the knowledge in the world where viscosities are headed to 0w8.
No engine manufacturer has "abandoned" HTHS viscosity concepts. Those engine engineers know all about it. If they don't know, then they shouldn't be designing engines. If CAFE wasn't choke holding manufacturers, the OMs in the USA would also show a range of recommended viscosity. Toyota OMs in the USA do have a statement to use higher viscosity for hard use. That's their basic round about way around CAFE to say thicker oil is better for hard use - obviously correct. And yes, it's been proven in many studies that higher HTHS with other factors held constant will protect engines better and result in less wear.
Been discussed many times here that engines specifying 16 and 8 have special design aspects to use those viscositys. They even have a different ILSAC designation and logo on the bottles so people don't use it in engines not designed to use it. Surely you've seen these many discussions here. And going a grade up on those engines will give added wear protection too.
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