My late father was an old school mechanic. He always told me it was better to run a high mileage vehicle on a heavier weight oil during hot weather. I now live in Oklahoma (used to live in IL). It's HOT here. We have a 95 Dodge Ram 1500 with 150,000 miles on it. I usually run 10W40 in the summer, 10W30 in the winter.

I just came from the auto parts store. Hubby forgot about dad's logic and got 10W30, so I went back to the store to exchange it. They questioned why I would want to run 40 in the summer, said 30 was recommended.

Are they wrong, or is my dad's logic flawed? Dad was born in 1923.

Thanks in advance for your thoughts!

 

Back when he was growing up engines were not made as tight as they are today so his knowledge for older engines is correct.

Now at least since the 70's engines have been built to closer tolerances between the main bearing and crank shaft as an example, and today with all the improvements using the factory recommended oil viscosity will work for most if not all of the engines life.

Lower viscosity oil also transfers heat better than higher viscosity oil

That said if you have an engine that is loosing oil pressure from very high mileage then it may pay to use a thicker oil. But the issue of wear will only get worse.

With yours at 150K I would not expect it to be having issues yet.

For Oklahoma using the 10w30 oil is what is recommend by the factory. And you can use it year around.

 

I agree with Mobile Auto Repair stay with 10/30

get back if there is a oil pressure issue in those dog days of summer.

PS dad was right - but things change -

 

I'm glad to know the auto parts store wasn't giving out faulty information. It seems like auto repairs around here are a constant game of "who do you trust?" We've recently had some problems with an auto parts (chain) store & don't shop there anymore. We just switched & that's where I heard about the 10W30 v. 10W40.

Being as I've followed most of dad's logic for decades now, we went ahead and put the 40 weight in the van, but before I read your posts. Internet was down for a while. I've used 10w40 in the summer for years now and it hasn't seemed to be a problem. However, I'm grateful & appreciate the update with more current info.

We do switch back to 10W30 in the fall. In just the past couple of years, we've noticed the van losing a quart of oil between changes, doesn't matter which oil we're running. Cannot figure where the oil is going, it's not visibly leaking, nor does it appear to be burning oil.

I've posted here before, but it's been a while. Overall, we have been pretty disappointed with the performance, amount of maintenance, ease of repairs and overall durability of this 1995 van, vs. the 1984 van (also a Dodge 1500) we used to have. That '86 beat this one, hands down! They just ain't making them like they used to!

 

oil loss- any smoke on start up- ck the plugs- may tell a story, black and wet would have me checking valve guides. OR sludge in oil returns

 

In my humble opinion the best thing you could do for your engine in terms of giving it protection would be to use a full synthetic oil year-round. It costs more but it's engineered better than conventional oil and will provide the best protection for your engine in a hot climate. Plus, you can go 5K miles between changes. Some say 7.5K-10K but I wouldn't recommend this.

Another thing to remember is a lighter weight oil in the crankcase is easier for your engine to pump through the oiling system, both at startup and at operating temperature. This translates into better fuel economy and better lubricity at all temperatures throughout the year.

Lastly, get a good filter. Use Wix, Amsoil or K&N. I think the Mopar filters are pretty good. Stay away from Fram (total garbage) or the value store brands like the Wal-Mart ST series filters.

 

I actually had to go and look this word up. I've never heard it before and thought you made it up. LOL

 

Thumbs up for Merriam-Webster online! At the risk of hijacking the thread here's something else to think about. Why do manufacturers call it "Motor Oil" and not "Engine Oil?"

I was taught that motors are electric and that engines use fuel to make power by combustion. Based on this we should be using Engine Oil, shouldn't we?

 

I guess you should've checked that Merriam-Webster site before posting.

http://www.merriam-webster.com/dictionary/motor
motor
Pronunciation: \ˈmō-tər\
Function: noun
Etymology: Latin, from movēre to move
Date: 1586
1: one that imparts motion ; specifically : prime mover
2: any of various power units that develop energy or impart motion: as a: a small compact engine b: internal combustion engine ; especially : a gasoline engine c: a rotating machine that transforms electrical energy into mechanical energy
3: motor vehicle ; especially : automobile
— mo·tor·dom \-dəm\ noun
— mo·tor·less \-ləs\ adjective

 

Guess so. Well, chalk up another demerit for my high school auto shop teacher. The engine v.s. motor argument was his pet topic for discussion. Another item on the list of bad things I learned during that semester -- some in school, some out.