oil for rarely used car

stangguy

stangguy

Joined
Jul 14, 2020
Messages
522
So for my 2 older cars that sit all winter, and in the warm months will sit for 1 to 4 weeks at a time between uses, which oil that I can pick up at Wally World would be the best to leave a film on the internal parts to prevent as much dry start as possible? The cars are 65 mustang with 200 c.i. 6 cyl and 98 mustang 3.8 6 cyl. Does heavier oil leave more film than thinner oil? I have been using 10w30 semi synthetic in both. Various brands. Also, they are never started when the ambient temp is below 50 degrees.
 
Any quality oil will be fine for those intervals. I would make sure that whatever you use has the appropriate additives for the engines. The fleet below all stay off the road for ~6 mos/year with a fresh oil change before hibernation. I use Mobil 1 or Redline in everything in my sig.
 
I’ve been using HM oils in the Firebird FORMULA in my signature usually in a 5W30 but I have used 10W30.
This most recent OCI(Oct ‘20) prior to this upcoming winter I put in 5W30 Rotella Gas Truck(RGT) full synthetic.
I haven’t used syn oil in this engine often over the past 40 yrs( maybe 3 X). And though not often either but, I have also used an HDEO on a few occasions. I only change the oil & filter every 2nd summers/fall.
 
Esthers cling less but non-synthetics have long term oxidation issues.

If you can pull the ignition and crank each engine some to build pressure before starting, then I would go with a synthetic.
 
I would say that clean conventional would be better than dirty synthetic for your stated goal. Generally, the biggest source of corrosive compounds are acids formed by blow by and moisture in the oil. The best way to limit corrosion is to change the oil before parking it and run it for a bit to wash away any corrosive compounds from the top of the engine.
 
Castrol Magnatec 5W30 (or any of the Magnatec range of oils that suit your viscosity requirements)
- easy to find
- affordable
- full synthetic (10W30 is still semi-synthetic)
- Dexos1-Gen2 rated
- contains organic polar molecule additives that are designed to attach to the metal surface of the engine (they give it a silly marketing name “intelligent molecules“ but it does work)



SR5 said:

Castrol GTX Magnatec

Anyone here try the Castrol GTX "Magnatec" full synthetic 5W-20 in a Ford 5.0L Coyote? It meets the Ford spec WSS-M2C945-A. Experience and thoughts?
bobistheoilguy.com

Shannow:
”Having discussed at length over dinner with a chemist who worked on the Magnatec programme, I'm a firm beleiver. (note, I'm not saying that others don't have something similar).”

“I asked if it was an ester, and he smiled, said he couldn't say but it wasn't far off. Stated also that their test regime (no details, other than it was an engine test) used a reference oil (M1 5W50 no less), a flushing oil, the test oil, flush oil, and then reference again to bookend the testing. Said that the residual surface agent was evident in the second flush, and on into the reference oil second run as well.”
Click to expand...
 
Castrol usually keeps mine quiet on start ups so I am sure it leaves a good film behind especially since mine has hydraulic lash adjusters which tick when it’s cold but don’t tick nearly as much using Castrol.
 
As far as I remember...I once read here on bitog a similar thread...and it was said that mineral oils are best for long term storage....

So I would use full saps 15w40 HDEO (ACEA E4/E7...more ZDDP...stronger oxidation resistance)
 
330indy said:
yeah..... before synthetics were invented
LOL
Click to expand...
BITOG is younger...and synthetic oils were invented in 70s...

I dont remember why....but it was strictly said that mineral oils are better for long term storage!

Its the same in guns subforum...plain mineral oil for long term storage is the best!
 
It’s all about the polarity of the organic molecules, the higher the better for attaching to a metal surface. I think it goes something like this (Chemists feel free to correct)

Ester > Group I > Group II > Group III > PAO (Group IV)
 
For 15 years I have used Valvoline Maxlife Synthetic 10w-30. My cheap Chonda mower is approaching 20 years and has had this oil since about 2006. Also using it in my riding mower that sits for weeks at a time, startups are quick and smoke free.
 
To prevent dry starts it would be more important that you use a high quality oil filter with a silicon check valve. As far as a clingy oil, I would try Castrol magnatec. That's how they advertise there product.
 
Long term storage requires an oil with a high TBN retention and having high TBN to start will allow it to last longer and fight acids better than an oil that starts out lower in TBN. For this reason a good high mileage synthetic, I feel, would serve the situation best.
 
I was just about to ask this question. I have a new 2020 4Runner that's been sitting in the garage since COVID came around in March. I did the oil change in 6/20, Drove 200 miles between then and now, now it's seldom used maybe once a month since then.

Should I look to change the oil due to this acid issue come June again? The vehicle is garage parked. I currently have PUP 0W-20 in it.
 
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