I didn't read that part of the caption.
Cold start at -35°F with 10W30 = no oil pressure
- Thread starter atikovi
- Start date
Started Opel Vectra B at -42c having 10W40 in the sump.
I’m wondering if there is possibly something wrong with his oil pump or oil system. Even with the 5w40 it takes a long time for oil pressure to come on, longer than I would have left it running to be honest.
Hinton,AB isnt very far from me and I’ve started many engines with 5wXX and 10wXX in those temps and didn’t have issues with oil pressure.
Hinton,AB isnt very far from me and I’ve started many engines with 5wXX and 10wXX in those temps and didn’t have issues with oil pressure.
OVERKILL
$100 Site Donor 2021
FWIW, the MRV limit used to be lower, like 42,000cP or 48,000cP or something, and the reason for that was that this was the limit for the AMC/Jeep 4.0L I6 oil pump + pickup combo. That was eventually deemed "obsolete" and the newer limit of 60,000cP adopted to reflect more modern applications.
We may be witnessing an artifact of that type of difference here.
How do you figure that?
Back in January and February 1963 living in rural DownEast Maine, the temperature went down below -20F for a few days. My 1962 Buick always started using 10W-40
(API “SB”). 10W-40 was the best oil of the day.
The previous year, although not as cold, I used the same oil in my 1960!Triumph TR3A. Always started.
Like dnewton pointed out, The real issue in those low temps is the addition of Lucas. Makes me cringe how thick that must be 
In -40F weather after a cold soak my TDI with Redline Euro/Ravenol VMP 5W30 504/507 would start and make pressure fairly normally. The graphic displays and speakers would not work until the cabin warmed up. The computer itself would not let the engine rev past about 1500 rpm and if you took off too soon the transmission locked you out above second gear for a few minutes. Glad those days are over with my retirement.
I'm in new Mexico where I usually doesn't get below -10f and I run 5w-30 group 3+ oil in my old dodge.
What are they thinking.
Torpedo heater!
I lived in Yellowknife for many years where -35C in winter is common. All my vehicles were equiped with oil pan heater, block heater and trickle charger, 2 hours before startup and a 1/2hr idle. The real engine killer is short trips and condensation in the crankcase that in extreme cases would freeze the oil pickup shut.
He said he had Lucas Oil Stabilizer in the sump, the really thick stuff. So this isn’t really a true representation of a 10w30 oil in extreme cold temperatures.
While 10w30 is not optimal for sure, it would’ve built oil pressure a lot sooner if it wasn’t handicapped by the Lucas junk additive.
While 10w30 is not optimal for sure, it would’ve built oil pressure a lot sooner if it wasn’t handicapped by the Lucas junk additive.
Unless of course, it couldn’t be pumped as it wasn’t here.
The winter rating sure seems to be a confusing subject for many people.
Not being able to be pumped is a poster child illustration of exactly what the winter rating represents.
OVERKILL
$100 Site Donor 2021
Absolutely. It's just typically that CCS is what hits the limit first, since that limit is much lower.
If we look at Formula Shell 10W-30 for example, the CCS limit is 7,000cP and the oil is 5,730cP. Given the "doubling rule", that means it'll be around 12,000cP at -30C, so there's no way it's qualifying for the 5W-xx Winter grade. On the other hand, if we look at MRV, at 17,300cP, doubled that's only ~35,000cP, well below the 60,000cP limit. This assumes predictable PPD behaviour of course.
That’s your assumption and you’re also assuming that the additive didn’t affect the pumpability, which it 100% did.
There is an old Mobil 1 video that compares a Dino 10w30 to their synthetic 5w30 that was done at -35c. 10w30 pumped in that video.
An oil doesn’t go from pumpable to not pumpable just because it’s few degrees outside of the cold grade rating.
No, I was agreeing in a way that the additive certainly may have affected that. It probably did.
And no, I also agree that a few degrees isn’t going to make a big difference. However that is exactly what the difference is. It’s either pumpable or it’s not. It is a binary. That old Mobil video probably illustrated the fallacy of using pour point for predicting borderline cold weather performance of an oil.
I’m not entirely convinced of the binary characteristics of the oil.
The wax crystals will form pretty slowly at first and there is a transient period where the oil is less pumpable, but pumpable non the less.
