im currently using rotella 15w40 in my 5.0 engine but winter is right around the corner and where i live the average winter temp is from -5 to 15 degrees. i know 15w40 is too thick for that so i was wondering if i could switch to the rotella 10w30 T5? would that be good enough for temperatures that low?

 

and yes i will be letting my truck warm up for a good 15 minutes before i start to drive it

 

I've used 5w-30 for those temps, manufacturer's research shows engine wear is greatest during a cold crank.

 

i dont think rotella makes a diesel oil in 5w30.........also i use the diesel oil for the zinc

 

Where I live the temps sometimes go down as far as -10. But our average winter temps usually 10-30 degrees.

And we've always used 10w-30 in all our trucks and we've had a 302, and currently have a 351 and a 460 and have never had a problem starting them in the winter.

 

okay thanks bud. all i needed to know

 

I thought Shell made a 5w40 diesel? I run 10w40 in my truck year round, it usually gets down to 20 here in winter

 

the 5w40 is expensive as hell here. the 10w30 is not too bad. i might try the 10w40 if it works well with you

 

<p>i use valvoline all fleet 15-40 in everything i own, been using it for over 40 years.</p><p>never had any problems with any engines, and it gets down to -10 on occasion here. but usual winter temps is between 0 and 15</p><p>&nbsp;average engine mileage is between 180 and 225k miles, with the exception of the 99 crown vic(73k), 04 F-350(17k),</p><p>and 88 F-Superduty diesel( 494k)</p><p>&nbsp;</p>

 

15W40 should be fine in my gas truck then. Its old too and i will be warming it up for a good 10-15 minutes before i start driving it

 

Have you installed a block heater?

 

Nope dont have a diesel nor do i have a location to plug one in

 

The winters for me usually don't get lower than the 20's on a regular basis, but I blend my usual Havoline 5W30 with a quart or two of 5W20. That's just me though, I know it's not a necessity.

I would say a thinner oil trumps higher zinc levels in this case. The 10W-30 T5 is a synthetic blend IIRC, and should do better that the 15W40 conventional Rotella as it relates to cold starts. Unless you're seeing high oil temps, the10W30 Rotella would be better suited for your truck that the 15W oil year round. No need for such a long warm up unless you just want a warm cab.

Keep in mind a 5W30 flows still flows better than a 10W30 at 100*F all things being equal, which is something you may want to consider.

 

You can install a heater in lower radiator hose to keep the block/coolant warmer, though you have to drain the cooling system to install it. I've had these in my previous vehicles (all gas engines) when I lived in colder climates. Makes for easier startups and I ran the same weight of oil all year round.

 

<p>but a block heater is no good if you can't plug it in.</p>