Hi guys, been a while since I've been one but I have a quick question. It's time for the first oil change after new injectors and rebuilt turbo (April, 2500 miles ago). I was digging through some old threads looking for the correct oil to use and one said 5w-40 helped with cold starts. I live in Portland, Oregon and it does not get ANY colder then 25°f (warmest in the summer is about 100°). It's in the 40's now and the truck will start but romps pretty bad unless I turn on high idle for about 10 seconds, lots of cold-start white smoke that clears after about a minute of idling. The GPs were replaced in April with OEM Fords, GP Rely is good.
I called my very helpful Ford service department and asked about running 5w-40. He had a very strong "NO" and you NEED to run 15w-40 out where I live. He told me to plug in the block heater and call it good. (Hes charging 79.99 for a 15w-40 oil change - Good?)
Summary- Is it bad to run 15w-40 where I live (Climate)? Is it worthwhile to run more-expensive 5w40? Any other issues that could be causing my issue?
Thanks for all the help!

 

I've been running 5w40 full synthetic year round in as many as three 7.3's at a time over the past 9 years, one of which for that entire time. In case you didn't notice, I'm in Birmingham, AL. Southern heat. No issues whatsoever.

Here's the reality... it's the cold viscosity of 5w which helps with the cold starts because it flows faster and more easily at cold temperatures so that your HPOP, turbo, and injectors get their proper lube more quickly. Once the oil reaches operating temperature, the 5w40 has an operating viscosity of a 40w oil. Sooo... if you use 15w40, you get a thicker viscosity on cold starts of a 15w oil, but in the end, you still have an operating viscosity of 40w just as with the 5w40.

That said... run it year round with absolutely no worries whatsoever!

Why should you believe me? Ive spent over 30 years as a chemical engineer in heavy manufacturing processes, and I also spent about 4 years in lubrication sales when my engineering work was slow. I only reached my conclusion to even switch to the 5w40 synthetic after many months of investigation and research into the synthetic oil technology, and that's why I've stuck with it ever since.

Hope that can help you feel better about running the 5w40.

 

There's nothing wrong with running 5w-40 if you want to. I did that down here in Texas for several oil changes when the local wally world started selling the Rotella 5w-40 for the same price as the regular 15w-40. Switched back then the pricing went back to normal.

Of course that was a couple hundred thousand miles ago. Didn't cause any leaks during either switch, and didn't cause any kind of harm long term (unless 555,000 miles isn't enough to be considered long term).

The price doesn't sound bad on the oil change. If you figure oil at around $15 a gallon on sale and you buy 4 gallons, plus a $10 Motorcraft filter, you're at $70 doing it yourself.

 

If Ford sold 5-40, he would have said yes. I run 5-40 all year, and the temps go as high as 110 in the summer.

 

Ford does sell 5w-40

 

And it's spendy

 

260,000 miles on my '97 with 5w40 even when I lived in Phoenix
202,000 on my excursion with 5w40 always in southern New Mexico and Arizona
last 50,000 on my 99 with 5w40 (don't know about the first 280,000)

 

I run delo 5w-40 year round and have had zero issues. It gets cold up here in Montana and 5w-40 is a must in the winter for sure.

 

You can bet that an oil that is certified for diesel use is OK to use on the old technology. HUEI engines are certainly helped on cold mornings by the 5 weight oil because of their "weird" injection systems. When the additive package wears out, the oil reverts to it's base value of 40 weight. And you are not loading the engine heavily when it is cold, so there is no harm to bearings running 5W40 when it is cold.

 

Thanks guys. I'm gonna call ford and insist that they use 5w-40. If they refuse or Jack the price up I'll just do it myself. I wanted them to do it because it was the same price as doing it myself, without having to deal with the 4 gallons of oil.

 

They will jack up the price because the 5w40 costs more.

 

Do it yourself, higher probability it will be done correctly and you will know it actually is 5-40W synthetic. Do I trust a dealer to do anything correctly and/or not commit some sort of fraud? No. For what they are charging you to do a 15-40 oil change, you could do a 5-40W synthetic change and buy some good beer to drink when you are done!

 

too bad I'm too young to drink

 

Well I guess we could drink a suds while watching you do oil change

 

I stand corrected... Thank you. I should have said "If the dealership had it in stock, they would have said yes."