Rookie Oil Question
 

I've been running Valvoline 5w30 since the first change in my 2003 Pro5. I figured it was readily available, name brand, and correct weigt for my climate according to the manual. The dudes at the auto parts store said that now that I have 50,000 miles I should be running heavier oil. What's the reasoning there? (They seemed to be speaking from traditional wisdom and wouldn't really clarify)
Have I done something unwise? (If you want to tell me which oil or weight to use, that's cool. I appreciate the advise, but I'd rather understand why you make a particular recommendation)

auto parts store workers know nothing...run what the manual suggests....

Some older cars will leak the lower viscosity oil, we wont! Your fine.

Although i have been running 10w30 for the life of the car (becuase our winters are rough) 5w30 should have no problem in atlanta.

So you're a Valvoline man, eh? 5w30 Valvoline is the right choice for you. I'm a Pennzoil guy, so I run 5w30 Pennzoil. (Sometimes Castrol)
Those grease monkeys are retarded! If your car was old and smoking or consuming a lot of oil, I could see going with a thicker oil, but there's no reason to change in a normal running, well kept modern car.
The old traditional wisdom about a 20 point split in viscosity (10w30 20w50, etc.) doesn't apply anymore now that the additives in oils have improved, that's why they recommend 5w30 for almost every climate, 5w is thinner when cold, so the engine gets better fuel mileage when it's not fully warmed up.
Zero, if your winters are truly rough, you might consider switching to 5w30, as it's better suited to cold weather than 10w30, your car might warm a little quicker and run better while it's still cold, and it will still give the same protection as 10w30 when the engine's fully warmed up.

Thanks guys! I figured it was something lke that.

Peas is correct. Cold cranking is the most critical time for lubrication. You will have unnecessary wear and tear with 10W when it's cold because it can't circulate as easily as 5W.
Don't want to cause it to be a smoker in its later years.

Well, I've been running Amsoil 5W30 for the last 2 years with no problems. The Amsoil oil is a synthetic blend which really helps in our cold winters up here in Canada. We normally see -35°C (-31°F) here in the west and it really makes a difference. You can actually pour the oil at those low temperatures compared to regular oil.

I recently saw that Mobil 1 also has a synthetic blend 0W30. Now that is interesting and I am thinking of switching.

Can someone answer this question for me, someone told me because of VIN Numbers, but why is it some manuals say 5w30 and some say 10w30
mine says 10

2001 ES protege

I think it's sort of an industry-wide shift to 5w30. They recommend it because you get better fuel efficiency when the engine is cold, possibly faster warm up, and thus fewer emissions. The sooner the engine heats up, the sooner the cat lights and starts doing its job.

hm.. i been running mobil 10w30... think i should switch? - and no cats :)

I dont think you can make the switch. but then again worst case would be that you would probably burn oil faster. depending on how old the engine is, i ahve been driving around for 160,000 km , so I dont know.

I made the switch to synthetic at 130,000 but kept the 10w30

its been 5000km and my oil level is in the middle of the H and L.

Since i think the oil is a bit thiner i would burn off a bit more.

who knows, running 5w30 wouldnt cause damage. i am no expert though, hahah so be kind

I suppose it could burn more oil when the engine's cold, but at operating temperature, 5w30 and 10w30 will effectively be the same viscosity.

hmmm, i use 20w50 castrol gtx

isnt that a tad think?

well the guys here say that's what we should use here, so that's what i use.