oil

[JIM Q]

I do not understand oil really I do not In the MH they have been putting mobil 1 10-30 but I was told since im going on a trip this summer to use 10-40 ?? my goldwing motor cycle been using 10-30 as well went on rt 66 with the bike last year and seem ok been up and down the road from florida to NJ every year for 5 years even in dec my question is the difference between 10-30 and 10-40 thanks

[scenic route]

Mobile 1 10W-30 is widely used and a good choice. I use it in our 8.1 WH. Here's a link that explains the subject better than I can...

Motor Oil Viscosity Grades Explained in Layman's Terms

[moisheh]

Do NOT use 10/40 oil. The VI's break down too easily. GM does not approve that weight of oil. Your owner's manual will tell you the recommended weight.

[JimM68]

Viscosity is thickness. A lower number is thin, a higher number is thick.
Thicker oil has more resistence to movement, and also more resistance to breaking down under pressure.


In a "multi-vis" oil, the first number is "cold" the second "hot" Remember, oil gets a lot thicker when it is cold, and a lot thinner when it is warm.

So, a 10w oil is the thinkness of 10 wieght oil when it is cold (it stays thinner when cold)

A w30 oil gets pretty thin when hot, w40 not quite as thin, and w50 (most racing oils) stay pretty thick when hot.

Manufacturers have recommended thinner oils in recent years to minimize rotating resistence so they get better fuel economy.
Many, including me, prefer a thicker oil when hot.
Still, a good 30 wieght oil is good for most any street / highway conditions.

[Bob and Inga]

Originally Posted by moisheh

Do NOT use 10/40 oil. The VI's break down too easily. GM does not approve that weight of oil. Your owner's manual will tell you the recommended weight.

Now this is logic that you simply cannot disagree with. For us

Ford Fusion 5W-20 per Ford
Bounder 5W-30 per Chevy/Workhorse
Onan 15W-40 per Onan (other weights optional)

that's what we do.

Bob

[jcthorne]

We simplfy and use one oil that meets the requirements of almost every engine we own.

Ford V10 Motorhome chassis
Onan Genset
Ford F-250 diesel pickup
HarleyDavidson motorcycle
Generac Home standby generator
12hp lawn mower

All use Rotella T6 synthetic 5W40 motor oil. Sure makes things simple only keeping bottles of one kind around.

Only vehicle I do not use it in is our Shelby GT500 which Ford requires a 5W50. We use Redline for that as the motorcraft and castrol brands have shown not to hold up past 2000 miles in that service.