My 2005 Suzuki Verona manual says to use ether 5W 30 or 10W 40 oil. I mistakenly used 5W 20 and had to drive it before I could change to the correct oil. The engine was smoother and ran better. Can I use this oil without damaging the vehicle at the next oil change? I’ve already replaced it with 5W 30 this time.
I suggest you stick with the recommended oil. I would use 5W 30.
Stick with the recommendation. If you are in a very cold area, and change it out for the summer, it should be OK, but why?
I vote with sticking to the OEM recommendation.
I too vote to stick with the manufacturer’s recommendation.
The second number references the “viscosity” at temp. Viscosity is resistance to flow. A lower number means that the oil will act like a lighter oil when hot. You want the appropriate resistance to flow at temp, as that’s what allows the pressurized fluid barrier to exist that protects your sleeve bearings (main and rod bearings) from touching one another. Said differently, it is that pressurzed oil that keeps these critical surfaces seperated from one another.
The manufacturer says you need to 5W 30 or 10W 40 to properly protect the engine. Who are we to disagree? They designed and tested the thing.
My 09 Toyota recomended 5W20, but the 2010 manual calls for 0W20. The reason for this is cold start protection. It is not as thick at cold temps and flows better, protecting the moving parts of the eng.
This is a great site on everything oil and explains it all. http://www.bobistheoilguy.com/cms/
It really has more to do with meeting CAFE standards and squeezing that extra faction of a MPG out of the car. My 2007 Toyota called for 5W30 oil for all seasons, but a more recent bulletin said 5W20 and sythetic 0W20 was OK. The dealers are pushing this now since they want to stock fewer types of oil.
If I wanted easy starting in very cold weather I would use 0W30 full synthetic in my Toyota.
In addition to CAFE standards, late model Toyota engines drive their variable valve timing off of engine oil hydraulics. So more is being required of an oil during a cold start than what was required in years past.
Good point Joe! All the more reason to have a low viscosity at startup and an oil with good body once it’s warmed up.
Car companies play the odds; the guy driving a fully loaded Toyota across the Mojave Desert in July with a supermarket 5W20 in the crankcase is a minority occuring event. But it will likely cause permanent engine damage in terms of excessive wear. On the other hand millions of US cars are parked outside in the winter without block heaters. Those starts cause high engine wear, and a 0W or 5W viscosity rating with a very low pour point allows easy starting with low engine wear.
The best oils have a very wide visocity range (Index) and a 0W30 synthetic is probably the best all round oil for US cars in the Northern states to maximize engine life.