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Oil weights

Discussion in 'General Mustang Discussion' started by RagTop, Apr 2, 2017.

  1. RagTop

    RagTop Old Grumpy

    Since I moved to the Sierra foothills almost five years ago, my Mustang has been struggling with the summer 100*+ temperatures. I have 50K miles on the rebuild and have been using Castrol 10W-30. It's beginning to show the effects of a three speed automatic and lower rear end gears (lots more rpms per mile). I am considering going to a heavier weight oil but am torn between the Castrol 10W-40 semi-synthetic or the Castrol 20W-50. I used the 20W-50 for years in a first generation Mazda RX7 I owned, and managed to avoid the dreaded apex seal failures so common in rotary engines. I doubt that the car would be seeing extremely low temps around here, so the 20W wouldn't be a problem. My rebuild included a high volume oil pump and, when the temperatures are around 70* with the 10W-30 it runs with the oil pressure gauge at about 7/8 gauge. When the weather heats up, the car runs with the oil pressure gauge registering between half and 1/3 depending on rpm, showing the effects of the heat on viscosity. I don't want to cause problems for the engine with excessive oil pressure either. Any advice would be gratefully accepted.
  2. Starfury

    Starfury Active Member

    If you're concerned about oil pressure, you really need to get an actual gauge on it. The factory gauge isn't telling you anything, really. "between half and 1/3" isn't a pressure.

    Also, if you're running a flat tappet cam, I would strongly consider a high-zinc oil. I run Valvoline VR-1 in my 331, which comes in 10W-30 and 20W-50 flavors. Mobile 1 15W-50 is also high-zinc.
  3. RagTop

    RagTop Old Grumpy

    I revisited a previous post that I wrote on the same subject and took the advice of an old friend, Jeff Tepper, and ordered a case of Kendall 20W-50. My engine is flat tappet and should benefit from the higher zinc levels in Kendall. Thanks for the reply.
  4. zray

    zray who said Beer ?

    I've had nothing but great results from using Mobil 1 15w-50. Plenty of Zinc / phosphorus too.

  5. c6fastback

    c6fastback Member

    I ran 20w50 for many years when I lived in Placerville and Sacramento . Dark blue car , black interior and no a/c was not fun after the car was parked all day .
  6. sportsroof69

    sportsroof69 STREET CAR

    I always run 20W50 VR1 in mine.
  7. RagTop

    RagTop Old Grumpy

    I have to share this story about WalMart. My knees and shoulders have gotten so bad that I really can't change my own oil anymore. I received a case of Kendall 20W-50 from Amazon and decided to pay WalMart the $10 plus the price of a filter to install the oil. How "technical" can that be? I arrive at the auto center with my '69 convertible and the kid who is receiving asks what engine it has in it. I say it's a 302 and that non-metric information doesn't compute on his hand held terminal. He asks if it's a 5.0L and I say yes, I suppose it is. I tell him I want to purchase a Motorcraft FL1A oil filter and he looks up the proper application for my "5.0L" and tells me that the FL1A is not the correct filter for my car. I tell him that every 231, 260, 289, 302 and 351W Ford engine has always used the FL1A filter and he says his hand held says it should be an F20. He finally defers to an old guy in the lube room and comes back and says that, despite company policy, he'll be able to install the FL1A in the car. We go inside the store and he picks the last FL1A off the shelf. Now I do some light shopping and sit and watch part of "Beauty and The Beast" on their little flat screen in the waiting room and the kid who greeted me initially comes to the door and says the guy doing my oil change wants to talk to me. Odd, but OK. The second kid tells me he can't do my oil change due to company policy. He has found that I have an oversized drain plug on the car and they are forbidden from touching those because they might strip out the oil pan when being tightened. I tell him that the reason why the car has had the oversized drain plug is because some mook who provided service to the previous owner twenty or more years ago stripped the factory plug and it wouldn't tighten and would constantly drip. When I bought the car nineteen years ago the first thing I did was an oil change and found that the pan was stripped. The simple solution is to install a self threading oversized drain plug which will "install" the proper thread size in the oil pan on the way in. It's been that way for a successful nineteen years. He says firm no and I buy the FL1A and take the car home where, with a lot of pain, I roll around on the driveway and do my own stinking oil change. At least they didn't use the United Airlines policy excuse and drag me out of the waiting room by the ankles.
    Mach1 Driver and Grabber70Mach like this.
  8. RagTop

    RagTop Old Grumpy

    At least my no A/C car has a drop top. I can't imagine operating a coupe or sedan up here without A/C. Especially a dark colored exterior and interior. I'll bet you could have baked bread in that car in the summer in Placerville. I used to park my 2000 Z28 with a black interior in my driveway and, on a normal summer afternoon, you'd have to wear oven mitts to deal with the black leather covered steering wheel.

    KBMWRS Think before you HATE.

    Ken let me know next time and I'll drop by and do it for you. No problem. Or you can drive down here. Doesn't matter to me. Just ask...I'll be there.
  10. c6fastback

    c6fastback Member

    Towel heat on steering wheel or sun reflector in windshield was mandatory along with sheepskin seat covers or a towel to sit on . Wearing shorts and sitting on hot black seats was brutal
  11. RagTop

    RagTop Old Grumpy

    Mike, pretty long run from Morgan Hill to Lincoln just to change my oil.:) Thanks for the offer though.
  12. KBMWRS

    KBMWRS Think before you HATE.

    Hey that's why i have a motorcycle or vette....I love to ride/drive. You just let me know I'll be there.

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