How bad is running 10w30 for an 05 v10 2v?

 

'05' V10 is a 3V and 5w20 is spec.

 

As scraprat pointed out, 5W20 is spec'd.

cheap dino, or premium dino or synthetic 10W30?
If cheap dino, avoid starting it up below about 30 degrees F and it will be fine.
If premium dino or synthetic, fine down to about 15 or 20.

'05 V10 would still be 2V in vans, class C motorhomes.

 

Good point I forgot about the motorhomes.
For $20 give or take why not just use spec for the oil change?

 

Well, above and beyond the desire to NOT have to stock multiple weights of oil if you're a multiple vehicle family...

There is quite a bit of data out there saying the current 5W20's are being so optimized for peak fuel economy that they are compromising a BIT on engine protection. Enough to cause premature failure? Almost certainly not. But if I was planning/needing to run this engine for 500K miles, I'd be using 10W30 to give it every possible chance to make it - as well as passionately avoiding cold starts!. Since 200K will be enough for my needs, I'll go for the extra couple points of fuel economy and use the 5W20. I already have to stock 5 different oils so why not 6???

The other reason is severe service. Like towing in the summer out here where night time temps rarely go under 70, and daytime can hit 115. Clearly don't need the cold start protection of a 5 weight, but the oil does get pretty toasty when pulling hard!

 

As far as running a thicker oil through these newer engines I think you would be doing more harm than good because of the tolerance of engine design. If worried about oil longevity and engine life it probably would be cheaper to change the oil a little more often or possibly switching over to a full synthetic type.
If you spend 25-50K dollars on a vehicle I personally am not going to test a non spec oil in the engine.
Yes there some people that keep their trucks to 500k, I think it's above the norm. Heck the average person gets tired of the vehicle after 3-4 years and trades for a new vehicle. 100k miles and the engine just got broke in. To get 200-300k miles on an engine is nothing now a days. This is if the vehicle was properly maintenance d of course. But than again I could be wrong.

 

I think this myth will just never die... ...but it should...

 

Speaking as an engineer... Yes, the tolerances are tight, and I really appreciate folks that acutally DO listen to our recommendations!
But they are not THAT tight where shifting one weight grade up or down will cause problems. Especially with modern lubricants being as good as they are.
Some will argue that shifting even two grades would be fine in most cases... and honestly, I don't have strong enough evidence/data to argue with them. But I would personally recommend against going two grades up if you have to start engine when below freezing.

 

Am thinking of changing to Shell Rotella 5-40 Synth., would this be OK, since I do a lot of towing an 11,000# Trailer?

 

I've run it in mine for just under two years with no issues.