No issues switchign back and forth in grades of oil. My old truck I use to switch based on teh season. In the summer I'd run 20W50 (oil pump issues and I wasn't going to pay $800 to fix a $500 truck) but that was too thick in the winter for the engine to turn over on really cold mornings (gotta love new england) so I'd run 10W40.
The only real issue is switching between synthetic and dino oil. Doing that is a waste of money as the synthetic oil can't build up a good coating when you constantly switch back and forth. You can go from Dino to Synth, but once you do, you should stick to synth.
For grades...easy way to remember
First number is what weight of oil it behaves like when cold. The lower the number, the more viscosity it has at lower temperatures. This is good as it allows for the oil to circulate to the parts quicker when the car is just started especially on cold winter mornings.
The second number is what weight of oil it behaves like when hot. Generally, a higher number means it degrades less at hotter temps and thus better protection since by the time the engine is hot and the oil is hot, usually oil flow is not an issue anymore. Higher numbers are usually better for most applications.
Now everything depends on your application.
In my Turbo Volvo, I run Mobil 1 0W40 synthetic year round. Gives me excellent cold start protection, and since it's a turbo, helps get the oil flowing there quickly as well. But also, since it's a turbo, it's a little rougher on oil, so the 40 weight is nice when it's hot. However, on a worn engine, a lower number means generally means you'll burn more oil as it doesn't hold up as well. That's one way to slow oil consumption, go up a grade in oil.
For my 99 mustang, I just use Mobil 1 10W30 year round.
My 65 mustang, I just switched to 10w40.
I think we may have the same issue once I started thinking about it. My problem really started occuring when the temps started going down. Now, my engine temps do not go above 170* and since I'm runnign 10W40, I'm wondering if my oil is too thick to get proper flow in cold temps, especially since my engine runs so cold.
I'm going to dive into it this weekend and check my rockers and do an oil change to see what I can find.
Slade
The only real issue is switching between synthetic and dino oil. Doing that is a waste of money as the synthetic oil can't build up a good coating when you constantly switch back and forth. You can go from Dino to Synth, but once you do, you should stick to synth.
For grades...easy way to remember
First number is what weight of oil it behaves like when cold. The lower the number, the more viscosity it has at lower temperatures. This is good as it allows for the oil to circulate to the parts quicker when the car is just started especially on cold winter mornings.
The second number is what weight of oil it behaves like when hot. Generally, a higher number means it degrades less at hotter temps and thus better protection since by the time the engine is hot and the oil is hot, usually oil flow is not an issue anymore. Higher numbers are usually better for most applications.
Now everything depends on your application.
In my Turbo Volvo, I run Mobil 1 0W40 synthetic year round. Gives me excellent cold start protection, and since it's a turbo, helps get the oil flowing there quickly as well. But also, since it's a turbo, it's a little rougher on oil, so the 40 weight is nice when it's hot. However, on a worn engine, a lower number means generally means you'll burn more oil as it doesn't hold up as well. That's one way to slow oil consumption, go up a grade in oil.
For my 99 mustang, I just use Mobil 1 10W30 year round.
My 65 mustang, I just switched to 10w40.
I think we may have the same issue once I started thinking about it. My problem really started occuring when the temps started going down. Now, my engine temps do not go above 170* and since I'm runnign 10W40, I'm wondering if my oil is too thick to get proper flow in cold temps, especially since my engine runs so cold.
I'm going to dive into it this weekend and check my rockers and do an oil change to see what I can find.
Slade
