What oil weights can you run?

[gfh77665]

I got a ton of oil almost free from a convenience store close out. Over 200 quarts! So, out of my huge selection of oils, what can I safely run in my 4.6L 1998 Expedition?

I have 5-30's, 10-30's, 10-40's, 15-40's, 20-50's, SAE 30's, and SAE 40's. I need to use up the 5-30's in my newer Honda van, so, what of the rest can I use? What are your experiences with heavier weights?

BTW, I do almost 100% highway cruising at 75 MPH, and I live in South TX, so its pretty hot most of the year and the "winters" are very brief...

 

[crowncrazy87]

Ahhh the great oil debate... This is just me and what I have heard from my mechanic. He would not reccomend using anything other than the spec 5w20 or 5w30. This was just his opinion based on what he has seen with engine failures and what customers said they used.

He said in his opinion it had to do with the oil pump and how over time it has problems with the thicker heavier oils. He also said that the small oil ports make it harder to move the thicker oil to where it needs to be.

 

[gfh77665]

I looked back at the previous owners records and I see the Exp. has had Pennzoil 10-30 its entire life. I know the '98 owners manual specs 5-30 (not 5-20), so, 10-30 "should" be fine. I am thinking in my climate and with my driving style I can use 10-30 for our very mild "winter", and maybe I can get away with 10-40's in our brutal summers. I think this because I am willing to bet 10-40 is thinner at 85-105 degrees than a 5-30 would be at 0-32 degrees, like owners in the northern USA encounter. Does my reasoning make since? Thanks for your advice.

 

[crowncrazy87]

You are probably correct. I have heard people say that in hot climates the oil will "shear" down.

He also said that he reccomends a new oil pump and timing components between 150-175k miles since those are the biggest causes of failures on high mileage engines that he has seen.

I trust this mechanics opinions a lot. As a Mennonite (kinda like amish but do use some modern conviences) he is very honest and trustworthy.

 

[gfh77665]

Thanks 87!

Anyone else have experiences with slightly thicker oil? Positive or negative I would appreciate hearing them, thanks.