Mobile 1 15W 50 in HP 418W

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I have a 1970 Mustang Mach 1 with a stroked HP 351w. I Changed the oil with Mobile 1 full synthetic 15W50 in Nov 2020. The car is stored in an attached garage in the winters with a dehumidifier running. I ran the car ~ 300 miles in 2021. Not much due to covid and no car shows. The car is back in storage until the spring 2022. So the next time its run the oil will have been in the crankcase for ~ 1.5 years and would be in it for another 6 months (250 - 500 miles). The question I have to the experts is, should I dump this oil due to the time in the crankcase now? Previously I ran oil in this car for ~500 mile and 1 year. I can repurpose it in a car (2001 trooper) that is driven much more. Feedback is appreciated. Alan
 
Oil, even Mobil1, is cheap insurance and I would change it because I am OCD, but you should be fine.

The big issue here is contaminants and potential corrosion and did you get the engine hot enough during the little use to fully boil off moisture that collects in an engine, especially during cold running.

I would change it, but that is me.
 
Thanks for the feedback. I did run it at full temperature when I put miles on it last summer. I live in a very humid climate (Oregon) so even with my dehumidifier, water absorption for full synthetic is still a question in my mind. I dump the gas out of my 950 holley for off season storage, so I am not very keen on starting it from time to time during the storage months. I read somewhere that a disadvantage of sythetic oil is additives can precipitate out during cold storage. I am going to reuse this oil in the trooper, so I get some good use out of it. New M1 15w50 will be added when I am ready to fire it up.
 

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Did you select that oil for the ZDDP content? Solid lifter cam? If so, RP HPS 5-30 has almost the same levels as M1 15-50 and would be much better for cold starts.
 
What filter is in it? I would use a full synthetic media filter, like Amsoil, Royal Purple, Wix XP/NAPA Platinum, even Fleetguard Stratapore-they have better moisture tolerance than a conventional or blend media filter.
 
Did you select that oil for the ZDDP content? Solid lifter cam? If so, RP HPS 5-30 has almost the same levels as M1 15-50 and would be much better for cold starts.
I didn't select it for the ZDDP content since it has a roller cam. I typically use royal purple 10W40 performance oil. Due to the high price of RP, I used M1 in it.
 
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What filter is in it? I would use a full synthetic media filter, like Amsoil, Royal Purple, Wix XP/NAPA Platinum, even Fleetguard Stratapore-they have better moisture tolerance than a conventional or blend media filter.
I always used a WIX XP but they seem to not be available around here anymore. It currently has a NAPA Platinium in it. The NAPA filter website says their gold and patinium filters are for synthetic oil and are good up to12 month.
 
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My non oil expert logic is as follows: Typically my car is run when ambient temp is 70 to 95 F. My full roller 418w is a looser build and has low oil pressure at idle when hot. As I remember... nothing lower than 10 PSI at 900 rpm with ligher oil. So I prefer using 10W40 to have a lttle higher oil pressure at idle (as I remember... 15 PSI +). I was reading a thread on here with a 427W (600 HP) and the engine builder recommended using 0W40 or 5W40. OK, similar motors, longer non use intervals ecs. How about using M1 ESP formula 0W40, ESP X3 0W40, or M1 FS 5W40? Any recommendations? Alan
 
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My non oil expert logic is as follows: Typically my car is run when ambient temp is 70 to 95 F. My full roller 418w is a looser build and has low oil pressure at idle when hot. As I remember... nothing lower than 10 PSI at 900 rpm with ligher oil. So I prefer using 10W40 to have a lttle higher oil pressure at idle (as I remember... 15 PSI +). I was reading a thread on here with a 427W (600 HP) and the engine builder recommended using 0W40 or 5W40. OK, similar motors, longer non use intervals ecs. How about using M1 ESP formula 0W40, ESP X3 0W40, or M1 FS 5W40? Any recommendations? Alan
M1 0w-40 is my favourite oil for a Windsor, though I run Delvac 1 5w-40 in our 351W GT-40 boat, because it's a tad heavier and the duty cycle is more similar to an OTR truck (lots of RPM for extended periods of high load).

The M1 FS 5w-40 sounds like a good choice.
 
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