So have I, in summer...I know it's fine. We get a tad hung up on viscocities, brands and who's rating is on first, imo.
GL,md

The engine is just fine. An oil that is to heavy will lead to higher fuel consumption, potential idle problems during very cold weather because of issues with heavy oil and the vanos system, and a miniscule increase in wear over the proper weight. I would rather see you use 5w-50 and change it every 7.5k than use the proper weight for 15-20k intervals.

but using Mobil 0w40 isnt there not enough protection during cold start?

Why would Mobil 1 0w-40 not give enought protection during cold starts?!! It is going to be thinner at any given temperature than just about any other oil choice when the oil is colder than 100f.

but isnt 0w for cold weather? so if you live in weather with warmer weather is it going to be ok??

Use Mobil 1 15w-50. I use that in all my vehicles, all year round, I've been using it for at least 10 years and I live in MD. I wouldnt dream of putting a 0 w oil in my car.

Viscosity is what keeps the engine parts from contacting each other through "hydrodynamic" lubrication (like hydorplaning tires). If the fluid film breaks down in a high heat situation due to a lack of viscosity moving parts will contact one another with serious consequences. Anti-wear additives help to minimize damage but simply cannot replace viscosity.

My response regarding Mobil 1 15W-50 was directed to the original poster of this string who stated the following: "Also, I live in the Texas heat...is 5W-30 safe or should I go with 15W-30?". In colder climates a lower viscosity oil is necessary for engine start-up, but in the "Texas heat" the 15W-50 is the best recommendation AND can be used year round in the Houston area.

I give up, go read through the thread I linked above, if you can't come to a conclusion based on the information in that thread, your on your own.


I love the continued comments about using "0w" oils. All the w refers to is the spec it meets for cold pumping, it has nothing to do with the thickness of an oil at operating temperature. A 0w-40, 5w-40, 10w-40, 15w-40, and 20w-40 are all the same thickness at operating temperature (12.5-16.5 cst @ 100c).

Good job, don't let progress stand in your way. You have been doing it that way, so it must be correct. Right? After all, people rode horses for hundreds of years before cars came along and all those stupid lemmings jumped on the car bandwagon. Same thing goes for all those stupid people that abandon the outhouse in favor of indoor plumbing. Lets not forget all those other people that abandon sailing ships for steam ships. Stupid them for wanting a faster more reliable method of navigating waterways.

So tell me where do you find leaded gas to put in your X-5? How did you convert it back to carbs?

OUCH!:rolleyes: