Kind of oil to use on dts

[98deville]

On my 2003 dts the manual book calls for 5w30 oil. On all my other cars (98 deville & 76 eldorado) I use 10w30 Castro GTX, The last oil change I did on the DTS I put 10w30 should I have put what the manual says - 5w30 or it just depends on where u live and on the weather?

[BodybyFisher]

Starting in 2000 roller CAMs were introduced, that eliminated the metal to metal rubbing elements. That is why in 2000 and newer 5W30 is used, prior to that 10W30 was spec'd and I have used 15W40 even for a level of safety due to the reduction in ZDDP.

[98deville]

so 5w30 in the dts instead od 10w30

[BodybyFisher]

The 03 can stand 5W, the 98 can not and needs 10W.

Can the 03 use 10W?, probably in the hot months, but I will let someone else answer that..

[Ranger]

My '03 DHS, my daughters '02 SLS and my other daughters '04 Grand Am all call for 5W30. I still use 10W30.

[JohnnyG]

For best fuel economy, and better overall performance, use exactly what the manual says, 5W-30. If you live in the very far north, where temps stay below 20°F for long periods of time, I'd even go to one of the newer 5W-20 oils. If you live in the desert, at the time of the year when temps can exceed 100°F for a while, use the 10W-30 or heavier oil.

Little is said here about the 5W-20 oils, but they have become one of the newest wonders of the petroleum world. Almost certainly synthetic in nature, very stable in temperature, minimal viscosity index improvers, great additive packs, and certified for use in a lot of modern engines, including some Ford truck engines. Depending on your personal driving situation (including geographical location) they might be just the thing for you.

[JasonA]

All of our engines can use 5W-30. They were not nearly as good a decade or so ago, so GM didn't recommend them. But nowadays, 5W-30 oils are appropriate for all of these engines. The thinner at cold start, the better. There's no reason to run a 10W-30 oil when decent 5W-30 oils are available. The difference in cold viscosity between a 10W- and a 5W- oil can be dramatic, especially when below 30-40*F outside.

The only reason I don't use 5W-20 oil in the Northstar is because its warm viscosity IS different from a 5W-30 or a 10W-30. Typically in the 8-9 cSt range vs. 10-11 cSt. Our Town & Country seems to run great on the 5W-20 oil, but I only use it because that's what Chrysler specs.

But the warm viscosity of a 5W-30 and 10W-30 oil is effectively the same. The only difference is that the 10W- oil will thicken more as it cools down. Not necessarily what you want in your engine, especially given the wintertime temperatures that you may see, depending on where you live.

So yes, 5W-30 in your 2000+ engine. And I'd even use it in your older Northstar as well.