Hemi oil weight, is it really that sensitive?

[GMBoy]

5W/30 in my 2016 Ram Limited 5.7L.....123k miles no issues. In my mind the 20wt oil is the wrong oil!

 

[demarpaint]

5W/30 in my 2016 Ram Limited 5.7L.....123k miles no issues. In my mind the 20wt oil is the wrong oil!

It would be the wrong oil in my mind too.

 

[OVERKILL]

It's a QC issue with the engine when the part is in the engine sold to the public. The nuance of this being a parts supplier issue falls on deaf ears as far as the buying public is concerned. Especially when the manufacture became aware of this years ago and continued to incorporate said part in their engines. If it were one or two years, i would agree with you.

I know, i know, I've defended the indefensible as a Hyundai fanboy as well with the Theta II engine failures.
Pot....meet Kettle.

But it affects all major brands that sell pushrod engines, so it's not a "HEMI issue", or even a Stellantis issue, it's a broad supplier issue, affecting multiple marques.

 

[Vitamin Yoda]

Okay, so I wanted to add some info to this thread:

I think there were some model years for RAM 1500 trucks with the Gen III HEMI, where they programmed the ECU to set an error code if it detected a higher operating viscosty than 5W-20. It would infer the viscosity by reading the oil temperature and oil pressure in a certain RPM range. I believe they stopped this annoyance after the 2013 model year. The HEMI will still set this code, but only at extremely low temperatures like -35C~-40C, and I believe it can even set it with 5W-20 at those temperatures (depending on the blend, of course). I think @OVERKILL knows more about this than I do.

 

[OVERKILL]

Okay, so I wanted to add some info to this thread:

I think there were some model years for RAM 1500 trucks with the Gen III HEMI, where they programmed the ECU to set an error code if it detected a higher operating viscosty than 5W-20. It would infer the viscosity by reading the oil temperature and oil pressure in a certain RPM range. I believe they stopped this annoyance after the 2013 model year. The HEMI will still set this code, but only at extremely low temperatures like -35C~-40C, and I believe it can even set it with 5W-20 at those temperatures (depending on the blend, of course). I think @OVERKILL knows more about this than I do.

Yes, the non-SRT's are programmed to infer viscosity from oil pressure and temperature and throw a code if there's a certain amount of deviation. Obviously, there's a considerable fudge factor employed, which is generally why running 5W-30 or even 0W-40 doesn't throw the code. Former use Clevy had an '06 Charger R/T that he ran M1 Euro 0W-40 in back when it was the 3.6cP HTHS sauce and he only got the code once, when it was like -35C in Winnipeg.

 

[wemay]

But it affects all major brands that sell pushrod engines, so it's not a "HEMI issue", or even a Stellantis issue, it's a broad supplier issue, affecting multiple marques.

Incredible how we've reached to this point in the industry.

 

[KrisZ]

What is the hot oil pressure at idle on these? I keep hearing that these cannot be idled for extended period of time.

 

[vwmaniaman]

I just use the oil that the original owner used and I have not had any issues. He always used Castrol GTX synthetic blend Hi mileage. My oil pressure runs about 1/4th on the gauge at idle and 4/5ths on the gauge when on the highway. Mine has 226K on it now and very quiet.

 

[racer12306]

What is the hot oil pressure at idle on these? I keep hearing that these cannot be idled for extended period of time.

With 5w20, at full temp, I think I was 38-39psi. Now on 5w30 I'm about 41-42psi based on the EVIC.

 

[OVERKILL]

What is the hot oil pressure at idle on these? I keep hearing that these cannot be idled for extended period of time.

At idle, in gear w/0W-20 and the oil hot, in the summer:

At idle, in park w/0W-20 and the oil hot, in the winter:

 

[hemioiler]

What is the hot oil pressure at idle on these? I keep hearing that these cannot be idled for extended period of time.

There is a correlation between idling and failure, but it doesn't mean that the one causes the other. Why does idling apparently take out one random lifter but the other 15 remain in perfect (relative to age) condition?

Why do some trucks reach 2000+ idle hours and 250,000 miles without failure and other trucks fail at < 500 idle hours?

I'm not convinced of the idling theory at all.

 

[hemioiler]

And apparently Ford's 7.3 has really low idle psi since it uses a variable displacement oil pump, somewhere around 7 to 10 psi at idle IIRC. I know they're different engines, but still, at idle an engine doesn't need a lot of oil pressure.

 

[Vitamin Yoda]

At idle, in gear w/0W-20 and the oil hot, in the summer:

At idle, in park w/0W-20 and the oil hot, in the winter:

That right there perfectly illustrates the relationship between ambient temperature and oil viscosity.

 

[OVERKILL]

There is a correlation between idling and failure, but it doesn't mean that the one causes the other. Why does idling apparently take out one random lifter but the other 15 remain in perfect (relative to age) condition?

Why do some trucks reach 2000+ idle hours and 250,000 miles without failure and other trucks fail at < 500 idle hours?

I'm not convinced of the idling theory at all.

Just my opinion on the matter, but I think there's some unintentional conflation with engine hours and idling, where the association is being made with idling while in reality, if you've got a roller or pin with the defective heat treating, it is only going to hold up for so long, and it doesn't matter if "so long" is achieved going down the road or sitting behind a billboard waiting for speeders.

 

[racer12306]

That right there perfectly illustrates the relationship between ambient temperature and oil viscosity.

I wouldn't go that far, there's a 9*C (16*F) difference in oil temp, that has more of a role than the ambient.

 

[OVERKILL]

I wouldn't go that far, there's a 9*C (16*F) difference in oil temp, that has more of a role than the ambient.

The oil never sees 104C in the winter, that's a summer only phenomenon, so ambient has a role in oil temp, which in turn has an impact on viscosity and oil pressure.

 

[hemioiler]

Just my opinion on the matter, but I think there's some unintentional conflation with engine hours and idling, where the association is being made with idling while in reality, if you've got a roller or pin with the defective heat treating, it is only going to hold up for so long, and it doesn't matter if "so long" is achieved going down the road or sitting behind a billboard waiting for speeders.

Agreed, the correlation appears to be "engine runtime", not specifically "idle time".

 

[CarbonSteel]

I mean, GM did the same thing, and so has Ford so...

Apparently the days of Federal Mongoloid selling them bulletproof roller lifters that will out-last the engine are long gone. Now we get premium ??? made from only the most questionable Chinesium, heat treated by toddlers, who might not get it quite right when their diapers are full and they are uncomfortable.

FIFY

 

[johnmyster]

I wouldn't go that far, there's a 9*C (16*F) difference in oil temp, that has more of a role than the ambient.

I'd say it's more than just a role. It's the cause.

If I knew nothing more about these engines, I'd guess it has a oil cooler that couples to coolant. We might see greater delta between oil and coolant if the engine is really working, causing further losses in oil pressure...especially if idling after significant efforts.

I say this as a person who watches oil pressure when towing heavy on steep grades. Our diesel will outpace the oil cooler and at a point, I fear piston jets exiting the chat. When I see oil pressure falling it's time to lighten up.

Modern cars have cameras all over them and internet data connections. The future is not far where the car not only knows you used a non-spec oil, it took a video of you doing it and uploaded it, blacklisting its own warranty and sending a ticket to you for violating CAFE conditions.

 

[kschachn]

Modern cars have cameras all over them and internet data connections. The future is not far where the car not only knows you used a non-spec oil, it took a video of you doing it and uploaded it, blacklisting its own warranty and sending a ticket to you for violating CAFE conditions.

Except that warranty has never been related to oil grade, unless it causes damage. The automaker doesn’t care like the government does. Automakers aren’t that stupid.