I live in Siberia where it sometimes gets to 40 below in winter, summers are in the 90’s. what weight oil should I use, different in summer and winter? and regular, synthetic, or blend? I have a Mazda Demio, 2002, and it was recently cleaned of oil sludge from when we bought it a month ago.
Use the oil recommended in the owner’s manual. The car was designed and built to operate in all climates, including Siberia.
I’m going to guess 5W30.
“Recently cleaned of oil sludge?” What does that mean?
Sounds like the engine had sludge, and they cleaned it. If you can, use synthetic.
If the engine was sludged then it likely has a few problems. Don’t get too enamored of this car.
For temps of -40…I’d use a full Synthetic oil.
But the sludge problem is something to be worried about. Any buildup of sludge that’s bad enough to have to have it removed has shortened the life of the vehicle. I’d be very leery of this engine.
But you now own it…So if you want to keep it…then I’d recommend full synthetic and change the oil no more then 5k miles…Because of the sludge issue…I’d consider changing it every 3k miles.
Are you able to use an engine block heater there? That would be good for the car (and your comfort).
Due to the sludging, I’d change the oil again in 1,000 to 2,000 miles. I’d also cut the oil filter open to see what it caught. If things look bad, I’d repeat the process in another 1,000 to 2,000 miles.
As others have said, you may have a damaged engine here, so keep your fingers crossed.
Synthetic motor oil at least for winter months is best choice by a long shot.
For -40F temps I too would go to synthetic.
When I lived in North Dakota I had a lower radiator hose heater. Those and block heaters are the two best. They used to sell heaters that would go in the dipstick tube also, but those are useless. Worse than useless, actually, because they give the user a false sense of security.
Of course, I don’t know if they have outside power plugs ins Siberia!
It won’t start at forty below, but a 0w-20 synthetic gives you your best chance…In the summer, 10w-30 or 10w-40 should be fine…
This is depressing. A couple mechanics saw the sludge problem and said we should change the engine which would cost around 1000 bucks. Another mechanic, who was recommended by a friend, said he could clean it and fix it for 600, so we did. Then it still didn’t run well, so he changed 12 of the valves for 200. It still has a clatter, and loses power after it warms up. Now he says we should sell the car.
Cleaning sludge is pretty much a waste of time and money in my opinion. If it’s badly sludged the damage has already been done and cleaning sludge will not turn back the clock.
Removing a valve cover, or covers, to clean sludge from rocker arms and whatnot is also a waste of time. The only benefit would be if oil return holes in the cylinder head are clogged and this is causing oil smoke due to oil pooling.